Initial revision.

diff --git a/Triangle/A.poly b/Triangle/A.poly
new file mode 100644 (file)
index 0000000..166a717
--- /dev/null
+++ b/Triangle/A.poly
@@ -0,0 +1,62 @@
+29 2 1 0
+1 0.200000 -0.776400 -0.57
+2 0.220000 -0.773200 -0.55
+3 0.245600 -0.756400 -0.51
+4 0.277600 -0.702000 -0.53
+5 0.488800 -0.207600 0.28
+6 0.504800 -0.207600 0.30
+7 0.740800 -0.739600 0
+8 0.756000 -0.761200 -0.01
+9 0.774400 -0.772400 0
+10 0.800000 -0.776400 0.02
+11 0.800000 -0.792400 0.01
+12 0.579200 -0.792400 -0.21
+13 0.579200 -0.776400 -0.2
+14 0.621600 -0.771600 -0.15
+15 0.633600 -0.762800 -0.13
+16 0.639200 -0.744400 -0.1
+17 0.620800 -0.684400 -0.06
+18 0.587200 -0.604400 -0.01
+19 0.360800 -0.604400 -0.24
+20 0.319200 -0.706800 -0.39
+21 0.312000 -0.739600 -0.43
+22 0.318400 -0.761200 -0.44
+23 0.334400 -0.771600 -0.44
+24 0.371200 -0.776400 -0.41
+25 0.371200 -0.792400 -0.42
+26 0.374400 -0.570000 -0.2
+27 0.574400 -0.570000 0
+28 0.473600 -0.330800 0.14
+29 0.200000 -0.792400 -0.59
+29 0
+1 29 1
+2 1 2
+3 2 3
+4 3 4
+5 4 5
+6 5 6
+7 6 7
+8 7 8
+9 8 9
+10 9 10
+11 10 11
+12 11 12
+13 12 13
+14 13 14
+15 14 15
+16 15 16
+17 16 17
+18 17 18
+19 18 19
+20 19 20
+21 20 21
+22 21 22
+23 22 23
+24 23 24
+25 24 25
+26 25 29
+27 26 27
+28 27 28
+29 28 26
+1
+1 0.47 -0.5

diff --git a/Triangle/Makefile b/Triangle/Makefile
new file mode 100644 (file)
index 0000000..e048c5a
--- /dev/null
+++ b/Triangle/Makefile
@@ -0,0 +1,111 @@
+# makefile for Triangle and Show Me
+#
+# Type "make" to compile Triangle and Show Me.
+#
+# After compiling, type "triangle -h" and "showme -h" to read instructions
+#   for using each of these programs.
+#
+# Type "make trilibrary" to compile Triangle as an object file (triangle.o).
+#
+# Type "make distclean" to delete all executable files.
+
+# SRC is the directory in which the C source files are, and BIN is the
+#   directory where you want to put the executable programs.  By default,
+#   both are the current directory.
+
+SRC = ./
+BIN = ./
+
+# CC should be set to the name of your favorite C compiler.
+
+CC = cc
+
+# CSWITCHES is a list of all switches passed to the C compiler.  I strongly
+#   recommend using the best level of optimization.  I also strongly
+#   recommend timing each level of optimization to see which is the
+#   best.  For instance, on my DEC Alpha using DEC's optimizing compiler,
+#   the -O2 switch generates a notably faster version of Triangle than the
+#   -O3 switch.  Go figure.
+#
+# By default, Triangle and Show Me use double precision floating point
+#   numbers.  If you prefer single precision, use the -DSINGLE switch.
+#   Double precision uses more memory, but improves the resolution of
+#   the meshes you can generate with Triangle.  It also reduces the
+#   likelihood of a floating exception due to overflow.  Also, it is
+#   much faster than single precision on 64-bit architectures like the
+#   DEC Alpha.  I recommend double precision unless you want to generate
+#   a mesh for which you do not have enough memory to use double precision.
+#
+# If yours is not a Unix system, use the -DNO_TIMER switch to eliminate the
+#   Unix-specific timer code.
+#
+# If you are modifying Triangle, I recommend using the -DSELF_CHECK switch
+#   while you are debugging.  Defining the SELF_CHECK symbol causes
+#   Triangle to include self-checking code.  Triangle will execute more
+#   slowly, however, so be sure to remove this switch before compiling a
+#   production version.
+#
+# If the size of the Triangle binary is important to you, you may wish to
+#   generate a reduced version of Triangle.  The -DREDUCED switch gets rid
+#   of all features that are primarily of research interest.  Specifically,
+#   defining the REDUCED symbol eliminates the -i, -F, -s, and -C switches.
+#   The -DCDT_ONLY switch gets rid of all meshing algorithms above and beyond
+#   constrained Delaunay triangulation.  Specifically, defining the CDT_ONLY
+#   symbol eliminates the -r, -q, -a, -S, and -s switches.  The REDUCED and
+#   CDT_ONLY symbols may be particularly attractive when Triangle is called
+#   by another program that does not need all of Triangle's features; in
+#   this case, these switches should appear as part of "TRILIBDEFS" below.
+#
+# On some systems, you may need to include -I/usr/local/include and/or
+#   -L/usr/local/lib in the compiler options to ensure that the X include
+#   files and libraries that Show Me needs are found.  If you get errors
+#   like "Can't find include file X11/Xlib.h", you need the former switch.
+#   Try compiling without them first; add them if that fails.
+#
+# An example CSWITCHES line is:
+#
+#   CSWITCHES = -O -DNO_TIMER -I/usr/local/include -L/usr/local/lib
+
+CSWITCHES = -O
+
+# TRILIBDEFS is a list of definitions used to compile an object code version
+#   of Triangle (triangle.o) to be called by another program.  The file
+#   "triangle.h" contains detailed information on how to call triangle.o.
+#
+# The -DTRILIBRARY should always be used when compiling Triangle into an
+#   object file.
+#
+# An example TRILIBDEFS line is:
+#
+#   TRILIBDEFS = -DTRILIBRARY -DREDUCED -DCDT_ONLY
+
+TRILIBDEFS = -DTRILIBRARY
+
+# RM should be set to the name of your favorite rm (file deletion program).
+
+RM = /bin/rm
+
+# The action starts here.
+
+all: $(BIN)triangle $(BIN)showme
+
+trilibrary: $(BIN)triangle.o $(BIN)tricall
+
+$(BIN)triangle: $(SRC)triangle.c
+       $(CC) $(CSWITCHES) -o $(BIN)triangle $(SRC)triangle.c -lm
+
+$(BIN)tricall: $(BIN)tricall.c $(BIN)triangle.o
+       $(CC) $(CSWITCHES) -o $(BIN)tricall $(SRC)tricall.c \
+               $(BIN)triangle.o -lm
+
+$(BIN)triangle.o: $(SRC)triangle.c $(SRC)triangle.h
+       $(CC) $(CSWITCHES) $(TRILIBDEFS) -c -o $(BIN)triangle.o \
+               $(SRC)triangle.c
+
+$(BIN)showme: $(SRC)showme.c
+       $(CC) $(CSWITCHES) -o $(BIN)showme $(SRC)showme.c -lX11
+
+clean: distclean
+
+distclean:
+       $(RM) $(BIN)triangle $(BIN)triangle.o $(BIN)showme

diff --git a/Triangle/README b/Triangle/README
new file mode 100644 (file)
index 0000000..571d568
--- /dev/null
+++ b/Triangle/README
@@ -0,0 +1,181 @@
+Triangle
+A Two-Dimensional Quality Mesh Generator and Delaunay Triangulator.
+Version 1.3
+
+Show Me
+A Display Program for Meshes and More.
+Version 1.3
+
+Copyright 1996 Jonathan Richard Shewchuk
+School of Computer Science
+Carnegie Mellon University
+5000 Forbes Avenue
+Pittsburgh, Pennsylvania  15213-3891
+Please send bugs and comments to jrs@cs.cmu.edu
+
+Created as part of the Archimedes project (tools for parallel FEM).
+Supported in part by NSF Grant CMS-9318163 and an NSERC 1967 Scholarship.
+There is no warranty whatsoever.  Use at your own risk.
+
+
+Triangle generates exact Delaunay triangulations, constrained Delaunay
+triangulations, and quality conforming Delaunay triangulations.  The
+latter can be generated with no small angles, and are thus suitable for
+finite element analysis.  Show Me graphically displays the contents of
+the geometric files used by Triangle.  Show Me can also write images in
+PostScript form.
+
+Information on the algorithms used by Triangle, including complete
+references, can be found in the comments at the beginning of the triangle.c
+source file.  Another listing of these references, with PostScript copies
+of some of the papers, is available from the Web page
+
+    http://www.cs.cmu.edu/~quake/triangle.research.html
+
+------------------------------------------------------------------------------
+
+These programs may be freely redistributed under the condition that the
+copyright notices (including the copy of this notice in the code comments
+and the copyright notice printed when the `-h' switch is selected) are
+not removed, and no compensation is received.  Private, research, and
+institutional use is free.  You may distribute modified versions of this
+code UNDER THE CONDITION THAT THIS CODE AND ANY MODIFICATIONS MADE TO IT
+IN THE SAME FILE REMAIN UNDER COPYRIGHT OF THE ORIGINAL AUTHOR, BOTH
+SOURCE AND OBJECT CODE ARE MADE FREELY AVAILABLE WITHOUT CHARGE, AND
+CLEAR NOTICE IS GIVEN OF THE MODIFICATIONS.  Distribution of this code as
+part of a commercial system is permissible ONLY BY DIRECT ARRANGEMENT
+WITH THE AUTHOR.  (If you are not directly supplying this code to a
+customer, and you are instead telling them how they can obtain it for
+free, then you are not required to make any arrangement with me.)
+
+------------------------------------------------------------------------------
+
+The files included in this distribution are:
+
+  README           The file you're reading now.
+  triangle.c       Complete C source code for Triangle.
+  showme.c         Complete C source code for Show Me.
+  triangle.h       Include file for calling Triangle from another program.
+  tricall.c        Sample program that calls Triangle.
+  makefile         Makefile for compiling Triangle and Show Me.
+  A.poly           A sample data file.
+
+Triangle and Show Me are each a single portable C file.  The easiest way to
+compile them is to edit and use the included makefile.  Before compiling,
+read the makefile, which describes your options, and edit it accordingly.
+You should specify:
+
+  The source and binary directories.
+
+  The C compiler and level of optimization.
+
+  Do you want single precision or double?  Do you want to leave out some of
+  Triangle's features to reduce the size of the executable file?
+
+  The "correct" directories for include files (especially X include files),
+  if necessary.
+
+Once you've done this, type "make" to compile the programs.  Alternatively,
+the files are usually easy to compile without a makefile:
+
+  cc -O -o triangle triangle.c -lm
+  cc -O -o showme showme.c -lX11
+
+On some systems, the C compiler won't be able to find the X include files
+or libraries, and you'll need to specify an include path or library path:
+
+  cc -O -I/usr/local/include -o showme showme.c -L/usr/local/lib -lX11
+
+However, on other systems (like my workstation), the latter incantation
+will cause the wrong files to be read, and the Show Me mouse buttons won't
+work properly in the main window.  Hence, try the "-I" and "-L" switches
+ONLY if the compiler fails without it.  (If you're using the makefile, you
+may edit it to add this switch.)
+
+Some processors, possibly including Intel x86 family and Motorola 68xxx
+family chips, are IEEE conformant but have extended length internal
+floating-point registers that may defeat Triangle's exact arithmetic
+routines by failing to cause enough roundoff error!  Typically, there is
+a way to set these internal registers so that they are rounded off to
+IEEE single or double precision format.  If you have such a processor,
+you should check your C compiler or system manuals to find out how to
+configure these internal registers to the precision you are using.
+Otherwise, the exact arithmetic routines won't be exact at all.
+Unfortunately, I don't have access to any such systems, and can't give
+advice on how to configure them.  These problems don't occur on any
+workstations I am aware of.  However, Triangle's exact arithmetic hasn't
+a hope of working on machines like the Cray C90 or Y-MP, which are not
+IEEE conformant and have inaccurate rounding.
+
+Triangle and Show Me both produce their own documentation.  Complete
+instructions are printed by invoking each program with the `-h' switch:
+
+  triangle -h
+  showme -h
+
+The instructions are long; you'll probably want to pipe the output to
+`more' or `lpr' or redirect it to a file.  Both programs give a short list
+of command line options if they are invoked without arguments (that is,
+just type `triangle' or `showme').  Alternatively, you may want to read
+the instructions on the World Wide Web.  The appropriate URLs are:
+
+  http://www.cs.cmu.edu/~quake/triangle.html
+  http://www.cs.cmu.edu/~quake/showme.html
+
+Try out Triangle on the enclosed sample file, A.poly:
+
+  triangle -p A
+  showme A.poly &
+
+Triangle will read the Planar Straight Line Graph defined by A.poly, and
+write its constrained Delaunay triangulation to A.1.node and A.1.ele.
+Show Me will display the figure defined by A.poly.  There are two buttons
+marked "ele" in the Show Me window; click on the top one.  This will cause
+Show Me to load and display the triangulation.
+
+For contrast, try running
+
+  triangle -pq A
+
+Now, click on the same "ele" button.  A new triangulation will be loaded;
+this one having no angles smaller than 20 degrees.
+
+To see a Voronoi diagram, try this:
+
+  cp A.poly A.node
+  triangle -v A
+
+Click the "ele" button again.  You will see the Delaunay triangulation of
+the points in A.poly, without the segments.  Now click the top "voro" button.
+You will see the Voronoi diagram corresponding to that Delaunay triangulation.
+Click the "Reset" button to see the full extent of the diagram.
+
+------------------------------------------------------------------------------
+
+If you wish to call Triangle from another program, instructions for doing
+so are contained in the file `triangle.h' (but read Triangle's regular
+instructions first!).  Also look at `tricall.c', which provides an example.
+
+Type "make trilibrary" to create triangle.o, a callable object file.
+Alternatively, the object file is usually easy to compile without a
+makefile:
+
+  cc -DTRILIBRARY -O -c triangle.c
+
+------------------------------------------------------------------------------
+
+If you use Triangle, and especially if you use it to accomplish real
+work, I would like very much to hear from you.  A short letter or email
+(to jrs@cs.cmu.edu) describing how you use Triangle will mean a lot to
+me.  The more people I know are using this program, the more easily I can
+justify spending time on improvements and on the three-dimensional
+successor to Triangle, which in turn will benefit you.  Also, I can put
+you on a list to receive email whenever a new version of Triangle is
+available.
+
+If you use a mesh generated by Triangle or plotted by Show Me in a
+publication, please include an acknowledgment as well.
+
+
+Jonathan Richard Shewchuk
+July 20, 1996

diff --git a/Triangle/depend b/Triangle/depend
new file mode 100644 (file)
index 0000000..8265ad6
--- /dev/null
+++ b/Triangle/depend
@@ -0,0 +1,3 @@
+showme.o: showme.c
+triangle.o: triangle.c
+tricall.o: tricall.c triangle.h

diff --git a/Triangle/showme.c b/Triangle/showme.c
new file mode 100644 (file)
index 0000000..6c4f0a9
--- /dev/null
+++ b/Triangle/showme.c
@@ -0,0 +1,3384 @@
+/*****************************************************************************/
+/*                                                                           */
+/*    ,d88^^o 888                                   o    o                   */
+/*    8888    888o^88,  o88^^o Y88b    o    /      d8b  d8b      o88^^8o     */
+/*    "Y88b   888  888 d888   b Y88b  d8b  /      d888bdY88b    d888  88b    */
+/*     "Y88b, 888  888 8888   8  Y888/Y88b/      / Y88Y Y888b   8888oo888    */
+/*    o  8888 888  888 q888   p   Y8/  Y8/      /   YY   Y888b  q888         */
+/*    "oo88P" 888  888  "88oo"     Y    Y      /          Y888b  "88oooo"    */
+/*                                                                           */
+/*  A Display Program for Meshes and More.                                   */
+/*  (showme.c)                                                               */
+/*                                                                           */
+/*  Version 1.3                                                              */
+/*  July 20, 1996                                                            */
+/*                                                                           */
+/*  Copyright 1996                                                           */
+/*  Jonathan Richard Shewchuk                                                */
+/*  School of Computer Science                                               */
+/*  Carnegie Mellon University                                               */
+/*  5000 Forbes Avenue                                                       */
+/*  Pittsburgh, Pennsylvania  15213-3891                                     */
+/*  jrs@cs.cmu.edu                                                           */
+/*                                                                           */
+/*  This program may be freely redistributed under the condition that the    */
+/*    copyright notices (including this entire header and the copyright      */
+/*    notice printed when the `-h' switch is selected) are not removed, and  */
+/*    no compensation is received.  Private, research, and institutional     */
+/*    use is free.  You may distribute modified versions of this code UNDER  */
+/*    THE CONDITION THAT THIS CODE AND ANY MODIFICATIONS MADE TO IT IN THE   */
+/*    SAME FILE REMAIN UNDER COPYRIGHT OF THE ORIGINAL AUTHOR, BOTH SOURCE   */
+/*    AND OBJECT CODE ARE MADE FREELY AVAILABLE WITHOUT CHARGE, AND CLEAR    */
+/*    NOTICE IS GIVEN OF THE MODIFICATIONS.  Distribution of this code as    */
+/*    part of a commercial system is permissible ONLY BY DIRECT ARRANGEMENT  */
+/*    WITH THE AUTHOR.  (If you are not directly supplying this code to a    */
+/*    customer, and you are instead telling them how they can obtain it for  */
+/*    free, then you are not required to make any arrangement with me.)      */
+/*                                                                           */
+/*  Hypertext instructions for Triangle are available on the Web at          */
+/*                                                                           */
+/*      http://www.cs.cmu.edu/~quake/showme.html                             */
+/*                                                                           */
+/*  Show Me was created as part of the Archimedes project in the School of   */
+/*    Computer Science at Carnegie Mellon University.  Archimedes is a       */
+/*    system for compiling parallel finite element solvers.  For further     */
+/*    information, see Anja Feldmann, Omar Ghattas, John R. Gilbert, Gary L. */
+/*    Miller, David R. O'Hallaron, Eric J. Schwabe, Jonathan R. Shewchuk,    */
+/*    and Shang-Hua Teng.  "Automated Parallel Solution of Unstructured PDE  */
+/*    Problems."  To appear in Communications of the ACM, we hope.           */
+/*                                                                           */
+/*  If you make any improvements to this code, please please please let me   */
+/*    know, so that I may obtain the improvements.  Even if you don't change */
+/*    the code, I'd still love to hear what it's being used for.             */
+/*                                                                           */
+/*  Disclaimer:  Neither I nor Carnegie Mellon warrant this code in any way  */
+/*    whatsoever.  Use at your own risk.                                     */
+/*                                                                           */
+/*****************************************************************************/
+
+/* For single precision (which will save some memory and reduce paging),     */
+/*   write "#define SINGLE" below.                                           */
+/*                                                                           */
+/* For double precision (which will allow you to display triangulations of   */
+/*   a finer resolution), leave SINGLE undefined.                            */
+
+/* #define SINGLE */
+
+#ifdef SINGLE
+#define REAL float
+#else
+#define REAL double
+#endif
+
+/* Maximum number of characters in a file name (including the null).         */
+
+#define FILENAMESIZE 1024
+
+/* Maximum number of characters in a line read from a file (including the    */
+/*   null).                                                                  */
+
+#define INPUTLINESIZE 512
+
+#define STARTWIDTH 414
+#define STARTHEIGHT 414
+#define MINWIDTH 50
+#define MINHEIGHT 50
+#define BUTTONHEIGHT 21
+#define BUTTONROWS 3
+#define PANELHEIGHT (BUTTONHEIGHT * BUTTONROWS)
+#define MAXCOLORS 64
+
+#define IMAGE_TYPES 7
+#define NOTHING -1
+#define NODE 0
+#define POLY 1
+#define ELE 2
+#define EDGE 3
+#define PART 4
+#define ADJ 5
+#define VORO 6
+
+#define STARTEXPLOSION 0.5
+
+#include <stdio.h>
+#include <string.h>
+#include <X11/Xlib.h>
+#include <X11/Xutil.h>
+#include <X11/Xatom.h>
+
+/* The following obscenity seems to be necessary to ensure that this program */
+/* will port to Dec Alphas running OSF/1, because their stdio.h file commits */
+/* the unpardonable sin of including stdlib.h.  Hence, malloc(), free(), and */
+/* exit() may or may not already be defined at this point.  I declare these  */
+/* functions explicitly because some non-ANSI C compilers lack stdlib.h.     */
+
+#ifndef _STDLIB_H_
+extern char *malloc();
+extern void free();
+extern void exit();
+extern double strtod();
+extern long strtol();
+#endif
+
+/* A necessary forward declaration.                                          */
+
+int load_image();
+
+Display *display;
+int screen;
+Window rootwindow;
+Window mainwindow;
+Window quitwin;
+Window leftwin;
+Window rightwin;
+Window upwin;
+Window downwin;
+Window resetwin;
+Window pswin;
+Window epswin;
+Window expwin;
+Window exppluswin;
+Window expminuswin;
+Window widthpluswin;
+Window widthminuswin;
+Window versionpluswin;
+Window versionminuswin;
+Window fillwin;
+Window nodewin[2];
+Window polywin[2];
+Window elewin[2];
+Window edgewin[2];
+Window partwin[2];
+Window adjwin[2];
+Window voronoiwin[2];
+
+int windowdepth;
+XEvent event;
+Colormap rootmap;
+XFontStruct *font;
+int width, height;
+int black, white;
+int showme_foreground;
+GC fontgc;
+GC blackfontgc;
+GC linegc;
+GC trianglegc;
+int colors[MAXCOLORS];
+XColor rgb[MAXCOLORS];
+int color;
+
+int start_image, current_image;
+int start_inc, current_inc;
+int loweriteration;
+int line_width;
+int loaded[2][IMAGE_TYPES];
+REAL xlo[2][IMAGE_TYPES], ylo[2][IMAGE_TYPES];
+REAL xhi[2][IMAGE_TYPES], yhi[2][IMAGE_TYPES];
+REAL xscale, yscale;
+REAL xoffset, yoffset;
+int zoom;
+
+int nodes[2], node_dim[2];
+REAL *nodeptr[2];
+int polynodes[2], poly_dim[2], polyedges[2], polyholes[2];
+REAL *polynodeptr[2], *polyholeptr[2];
+int *polyedgeptr[2];
+int elems[2], ele_corners[2];
+int *eleptr[2];
+int edges[2];
+int *edgeptr[2];
+REAL *normptr[2];
+int subdomains[2];
+int *partpart[2];
+REAL *partcenter[2], *partshift[2];
+int adjsubdomains[2];
+int *adjptr[2];
+int vnodes[2], vnode_dim[2];
+REAL *vnodeptr[2];
+int vedges[2];
+int *vedgeptr[2];
+REAL *vnormptr[2];
+int firstnumber[2];
+
+int quiet, fillelem, bw_ps, explode;
+REAL explosion;
+
+char filename[FILENAMESIZE];
+char nodefilename[2][FILENAMESIZE];
+char polyfilename[2][FILENAMESIZE];
+char elefilename[2][FILENAMESIZE];
+char edgefilename[2][FILENAMESIZE];
+char partfilename[2][FILENAMESIZE];
+char adjfilename[2][FILENAMESIZE];
+char vnodefilename[2][FILENAMESIZE];
+char vedgefilename[2][FILENAMESIZE];
+
+char *colorname[] = {"aquamarine", "red", "green yellow", "magenta",
+                     "yellow", "green", "orange", "blue",
+                     "white", "sandy brown", "cyan", "moccasin",
+                     "cadet blue", "coral", "cornflower blue", "sky blue",
+                     "firebrick", "forest green", "gold", "goldenrod",
+                     "gray", "hot pink", "chartreuse", "pale violet red",
+                     "indian red", "khaki", "lavender", "light blue",
+                     "light gray", "light steel blue", "lime green", "azure",
+                     "maroon", "medium aquamarine", "dodger blue", "honeydew",
+                     "medium orchid", "medium sea green", "moccasin",
+                     "medium slate blue", "medium spring green",
+                     "medium turquoise", "medium violet red",
+                     "orange red", "chocolate", "light goldenrod",
+                     "orchid", "pale green", "pink", "plum",
+                     "purple", "salmon", "sea green",
+                     "sienna", "slate blue", "spring green",
+                     "steel blue", "tan", "thistle", "turquoise",
+                     "violet", "violet red", "wheat",
+                     "yellow green"};
+
+void syntax()
+{
+  printf("showme [-bfw_Qh] input_file\n");
+  printf("    -b  Black and white PostScript (default is color).\n");
+  printf("    -f  Fill triangles of partitioned mesh with color.\n");
+  printf("    -w  Set line width to some specified number.\n");
+  printf("    -Q  Quiet:  No terminal output except errors.\n");
+  printf("    -h  Help:  Detailed instructions for Show Me.\n");
+  exit(0);
+}
+
+void info()
+{
+  printf("Show Me\n");
+  printf("A Display Program for Meshes and More.\n");
+  printf("Version 1.3\n\n");
+  printf(
+"Copyright 1996 Jonathan Richard Shewchuk  (bugs/comments to jrs@cs.cmu.edu)\n"
+);
+  printf("School of Computer Science / Carnegie Mellon University\n");
+  printf("5000 Forbes Avenue / Pittsburgh, Pennsylvania  15213-3891\n");
+  printf(
+"Created as part of the Archimedes project (tools for parallel FEM).\n");
+  printf(
+"Supported in part by NSF Grant CMS-9318163 and an NSERC 1967 Scholarship.\n");
+  printf("There is no warranty whatsoever.  Use at your own risk.\n");
+#ifdef SINGLE
+  printf("This executable is compiled for single precision arithmetic.\n\n\n");
+#else
+  printf("This executable is compiled for double precision arithmetic.\n\n\n");
+#endif
+  printf(
+"Show Me graphically displays the contents of geometric files, especially\n");
+  printf(
+"those generated by Triangle, my two-dimensional quality mesh generator and\n"
+);
+  printf(
+"Delaunay triangulator.  Show Me can also write images in PostScript form.\n");
+  printf(
+"Show Me is also useful for checking the consistency of the files you create\n"
+);
+  printf(
+"as input to Triangle; Show Me does these checks more thoroughly than\n");
+  printf("Triangle does.  The command syntax is:\n\n");
+  printf("showme [-bfw_Qh] input_file\n\n");
+  printf(
+"The underscore indicates that a number should follow the -w switch.\n");
+  printf(
+"input_file may be one of several types of file.  It must have extension\n");
+  printf(
+".node, .poly, .ele, .edge, .part, or .adj.  If no extension is provided,\n");
+  printf(
+"Show Me will assume the extension .ele.  A .node file represents a set of\n");
+  printf(
+"points; a .poly file represents a Planar Straight Line Graph; an .ele file\n"
+);
+  printf(
+"(coupled with a .node file) represents the elements of a mesh or the\n");
+  printf(
+"triangles of a triangulation; an .edge file (coupled with a .node file)\n");
+  printf(
+"represents a set of edges; a .part file specifies a partition of a mesh;\n");
+  printf(
+"and a .adj file represents the adjacency graph defined by a partition.\n");
+  printf("\n");
+  printf("Command Line Switches:\n");
+  printf("\n");
+  printf(
+"    -b  Makes all PostScript output black and white.  If this switch is not\n"
+);
+  printf(
+"        selected, color PostScript is used for partitioned meshes and\n");
+  printf("        adjacency graphs (.part and .adj files).\n");
+  printf(
+"    -f  On color displays and in color PostScript, displays partitioned\n");
+  printf(
+"        meshes by filling triangles with color, rather than by coloring the\n"
+);
+  printf(
+"        edges.  This switch will result in a clearer picture if all\n");
+  printf(
+"        triangles are reasonably large, and a less clear picture if small\n");
+  printf(
+"        triangles are present.  (There is also a button to toggle this\n");
+  printf("        behavior.)\n");
+  printf(
+"    -w  Followed by an integer, specifies the line width used in all\n");
+  printf(
+"        images.  (There are also buttons to change the line width.)\n");
+  printf(
+"    -Q  Quiet:  Suppresses all explanation of what Show Me is doing, unless\n"
+);
+  printf("        an error occurs.\n");
+  printf("    -h  Help:  Displays these instructions.\n");
+  printf("\n");
+  printf("Controls:\n");
+  printf("\n");
+  printf(
+"  To zoom in on an image, point at the location where you want a closer\n");
+  printf(
+"  look, and click the left mouse button.  To zoom out, click the right\n");
+  printf(
+"  mouse button.  In either case, the point you click on will be centered in\n"
+);
+  printf(
+"  the window.  If you want to know the coordinates of a point, click the\n");
+  printf(
+"  middle mouse button; the coordinates will be printed on the terminal you\n"
+);
+  printf("  invoked Show Me from.\n\n");
+  printf(
+"  If you resize the window, the image will grow or shrink to match.\n");
+  printf("\n");
+  printf(
+"  There is a panel of control buttons at the bottom of the Show Me window:\n"
+);
+  printf("\n");
+  printf("  Quit:  Shuts down Show Me.\n");
+  printf("  <, >, ^, v:  Moves the image in the indicated direction.\n");
+  printf(
+"  Reset: Unzooms and centers the image in the window.  When you switch from\n"
+);
+  printf(
+"    one image to another, the viewing region does not change, so you may\n");
+  printf(
+"    need to reset the new image to make it fully visible.  This often is\n");
+  printf(
+"    the case when switching between Delaunay triangulations and their\n");
+  printf(
+"    corresponding Voronoi diagrams, as Voronoi vertices can be far from the\n"
+);
+  printf("    initial point set.\n");
+  printf(
+"  Width+, -:  Increases or decreases the width of all lines and points.\n");
+  printf(
+"  Exp, +, -:  These buttons appear only when you are viewing a partitioned\n"
+);
+  printf(
+"    mesh (.part file).  `Exp' toggles between an exploded and non-exploded\n"
+);
+  printf(
+"    image of the mesh.  The non-exploded image will not show the partition\n"
+);
+  printf(
+"    on a black and white monitor.  `+' and `-' allow you to adjust the\n");
+  printf(
+"    spacing between pieces of the mesh to better distinguish them.\n");
+  printf(
+"  Fill:  This button appears only when you are viewing a partitioned mesh\n");
+  printf(
+"    (.part file).  It toggles between color-filled triangles and colored\n");
+  printf(
+"    edges (as the -f switch does).  Filled triangles look better when all\n");
+  printf(
+"    triangles are reasonably large; colored edges look better when there\n");
+  printf("    are very small triangles present.\n");
+  printf(
+"  PS:  Creates a PostScript file containing the image you are viewing.  If\n"
+);
+  printf(
+"    the -b switch is selected, all PostScript output will be black and\n");
+  printf(
+"    white; otherwise, .part.ps and .adj.ps files will be color, independent\n"
+);
+  printf(
+"    of whether you are using a color monitor.  Normally the output will\n");
+  printf(
+"    preserve the properties of the image you see on the screen, including\n");
+  printf(
+"    zoom and line width; however, if black and white output is selected (-b\n"
+);
+  printf(
+"    switch), partitioned meshes will always be drawn exploded.  The output\n"
+);
+  printf(
+"    file name depends on the image being viewed.  If you want several\n");
+  printf(
+"    different snapshots (zooming in on different parts) of the same object,\n"
+);
+  printf(
+"    you'll have to rename each file after Show Me creates it so that it\n");
+  printf("    isn't overwritten by the next snapshot.\n");
+  printf(
+"  EPS:  Creates an encapsulated PostScript file, suitable for inclusion in\n"
+);
+  printf(
+"    documents.  Otherwise, this button is just like the PS button.  (The\n");
+  printf(
+"    main difference is that .eps files lack a `showpage' command at the\n");
+  printf("    end.)\n\n");
+  printf(
+"  There are two nearly-identical rows of buttons that load different images\n"
+);
+  printf("  from disk.  Each row contains the following buttons:\n\n");
+  printf("  node:  Loads a .node file.\n");
+  printf(
+"  poly:  Loads a .poly file (and possibly an associated .node file).\n");
+  printf("  ele:  Loads an .ele file (and associated .node file).\n");
+  printf("  edge:  Loads an .edge file (and associated .node file).\n");
+  printf(
+"  part:  Loads a .part file (and associated .node and .ele files).\n");
+  printf(
+"  adj:  Loads an .adj file (and associated .node, .ele, and .part files).\n");
+  printf("  voro:  Loads a .v.node and .v.edge file for a Voronoi diagram.\n");
+  printf("\n");
+  printf(
+"  Each row represents a different iteration number of the geometry files.\n");
+  printf(
+"  For a full explanation of iteration numbers, read the instructions for\n");
+  printf(
+"  Triangle.  Briefly, iteration numbers are used to allow a user to easily\n"
+);
+  printf(
+"  represent a sequence of related triangulations.  Iteration numbers are\n");
+  printf(
+"  used in the names of geometry files; for instance, mymesh.3.ele is a\n");
+  printf(
+"  triangle file with iteration number three, and mymesh.ele has an implicit\n"
+);
+  printf("  iteration number of zero.\n\n");
+  printf(
+"  The control buttons at the right end of each row display the two\n");
+  printf(
+"  iterations currently under view.  These buttons can be clicked to\n");
+  printf(
+"  increase or decrease the iteration numbers, and thus conveniently view\n");
+  printf("  a sequence of meshes.\n\n");
+  printf(
+"  Show Me keeps each file in memory after loading it, but you can force\n");
+  printf(
+"  Show Me to reread a set of files (for one iteration number) by reclicking\n"
+);
+  printf(
+"  the button that corresponds to the current image.  This is convenient if\n"
+);
+  printf("  you have changed a geometry file.\n\n");
+  printf("File Formats:\n\n");
+  printf(
+"  All files may contain comments prefixed by the character '#'.  Points,\n");
+  printf(
+"  segments, holes, triangles, edges, and subdomains must be numbered\n");
+  printf(
+"  consecutively, starting from either 1 or 0.  Whichever you choose, all\n");
+  printf(
+"  input files must be consistent (for any single iteration number); if the\n"
+);
+  printf(
+"  nodes are numbered from 1, so must be all other objects.  Show Me\n");
+  printf(
+"  automatically detects your choice while reading a .node (or .poly) file.\n"
+);
+  printf("  Examples of these file formats are given below.\n\n");
+  printf("  .node files:\n");
+  printf(
+"    First line:  <# of points> <dimension (must be 2)> <# of attributes>\n");
+  printf(
+"                                           <# of boundary markers (0 or 1)>\n"
+);
+  printf(
+"    Remaining lines:  <point #> <x> <y> [attributes] [boundary marker]\n");
+  printf("\n");
+  printf(
+"    The attributes, which are typically floating-point values of physical\n");
+  printf(
+"    quantities (such as mass or conductivity) associated with the nodes of\n"
+);
+  printf(
+"    a finite element mesh, are ignored by Show Me.  Show Me also ignores\n");
+  printf(
+"    boundary markers.  See the instructions for Triangle to find out what\n");
+  printf("    attributes and boundary markers are.\n\n");
+  printf("  .poly files:\n");
+  printf(
+"    First line:  <# of points> <dimension (must be 2)> <# of attributes>\n");
+  printf(
+"                                           <# of boundary markers (0 or 1)>\n"
+);
+  printf(
+"    Following lines:  <point #> <x> <y> [attributes] [boundary marker]\n");
+  printf("    One line:  <# of segments> <# of boundary markers (0 or 1)>\n");
+  printf(
+"    Following lines:  <segment #> <endpoint> <endpoint> [boundary marker]\n");
+  printf("    One line:  <# of holes>\n");
+  printf("    Following lines:  <hole #> <x> <y>\n");
+  printf("    [Optional additional lines that are ignored]\n\n");
+  printf(
+"    A .poly file represents a Planar Straight Line Graph (PSLG), an idea\n");
+  printf(
+"    familiar to computational geometers.  By definition, a PSLG is just a\n");
+  printf(
+"    list of points and edges.  A .poly file also contains some additional\n");
+  printf("    information.\n\n");
+  printf(
+"    The first section lists all the points, and is identical to the format\n"
+);
+  printf(
+"    of .node files.  <# of points> may be set to zero to indicate that the\n"
+);
+  printf(
+"    points are listed in a separate .node file; .poly files produced by\n");
+  printf(
+"    Triangle always have this format.  When Show Me reads such a file, it\n");
+  printf("    also reads the corresponding .node file.\n\n");
+  printf(
+"    The second section lists the segments.  Segments are edges whose\n");
+  printf(
+"    presence in a triangulation produced from the PSLG is enforced.  Each\n");
+  printf(
+"    segment is specified by listing the indices of its two endpoints.  This\n"
+);
+  printf(
+"    means that its endpoints must be included in the point list.  Each\n");
+  printf(
+"    segment, like each point, may have a boundary marker, which is ignored\n"
+);
+  printf("    by Show Me.\n\n");
+  printf(
+"    The third section lists holes and concavities that are desired in any\n");
+  printf(
+"    triangulation generated from the PSLG.  Holes are specified by\n");
+  printf("    identifying a point inside each hole.\n\n");
+  printf("  .ele files:\n");
+  printf(
+"    First line:  <# of triangles> <points per triangle> <# of attributes>\n");
+  printf(
+"    Remaining lines:  <triangle #> <point> <point> <point> ... [attributes]\n"
+);
+  printf("\n");
+  printf(
+"    Points are indices into the corresponding .node file.  Show Me ignores\n"
+);
+  printf(
+"    all but the first three points of each triangle; these should be the\n");
+  printf(
+"    corners listed in counterclockwise order around the triangle.  The\n");
+  printf("    attributes are ignored by Show Me.\n\n");
+  printf("  .edge files:\n");
+  printf("    First line:  <# of edges> <# of boundary markers (0 or 1)>\n");
+  printf(
+"    Following lines:  <edge #> <endpoint> <endpoint> [boundary marker]\n");
+  printf("\n");
+  printf(
+"    Endpoints are indices into the corresponding .node file.  The boundary\n"
+);
+  printf("    markers are ignored by Show Me.\n\n");
+  printf(
+"    In Voronoi diagrams, one also finds a special kind of edge that is an\n");
+  printf(
+"    infinite ray with only one endpoint.  For these edges, a different\n");
+  printf("    format is used:\n\n");
+  printf("        <edge #> <endpoint> -1 <direction x> <direction y>\n\n");
+  printf(
+"    The `direction' is a floating-point vector that indicates the direction\n"
+);
+  printf("    of the infinite ray.\n\n");
+  printf("  .part files:\n");
+  printf("    First line:  <# of triangles> <# of subdomains>\n");
+  printf("    Remaining lines:  <triangle #> <subdomain #>\n\n");
+  printf(
+"    The set of triangles is partitioned by a .part file; each triangle is\n");
+  printf("    mapped to a subdomain.\n\n");
+  printf("  .adj files:\n");
+  printf("    First line:  <# of subdomains>\n");
+  printf("    Remaining lines:  <adjacency matrix entry>\n\n");
+  printf(
+"    An .adj file represents adjacencies between subdomains (presumably\n");
+  printf("    computed by a partitioner).  The first line is followed by\n");
+  printf(
+"    (subdomains X subdomains) lines, each containing one entry of the\n");
+  printf(
+"    adjacency matrix.  A nonzero entry indicates that two subdomains are\n");
+  printf("    adjacent (share a point).\n\n");
+  printf("Example:\n\n");
+  printf(
+"  Here is a sample file `box.poly' describing a square with a square hole:\n"
+);
+  printf("\n");
+  printf(
+"    # A box with eight points in 2D, no attributes, no boundary marker.\n");
+  printf("    8 2 0 0\n");
+  printf("    # Outer box has these vertices:\n");
+  printf("     1   0 0\n");
+  printf("     2   0 3\n");
+  printf("     3   3 0\n");
+  printf("     4   3 3\n");
+  printf("    # Inner square has these vertices:\n");
+  printf("     5   1 1\n");
+  printf("     6   1 2\n");
+  printf("     7   2 1\n");
+  printf("     8   2 2\n");
+  printf("    # Five segments without boundary markers.\n");
+  printf("    5 0\n");
+  printf("     1   1 2          # Left side of outer box.\n");
+  printf("     2   5 7          # Segments 2 through 5 enclose the hole.\n");
+  printf("     3   7 8\n");
+  printf("     4   8 6\n");
+  printf("     5   6 5\n");
+  printf("    # One hole in the middle of the inner square.\n");
+  printf("    1\n");
+  printf("     1   1.5 1.5\n\n");
+  printf(
+"  After this PSLG is triangulated by Triangle, the resulting triangulation\n"
+);
+  printf(
+"  consists of a .node and .ele file.  Here is the former, `box.1.node',\n");
+  printf("  which duplicates the points of the PSLG:\n\n");
+  printf("    8  2  0  0\n");
+  printf("       1    0  0\n");
+  printf("       2    0  3\n");
+  printf("       3    3  0\n");
+  printf("       4    3  3\n");
+  printf("       5    1  1\n");
+  printf("       6    1  2\n");
+  printf("       7    2  1\n");
+  printf("       8    2  2\n");
+  printf("    # Generated by triangle -pcBev box\n");
+  printf("\n");
+  printf("  Here is the triangulation file, `box.1.ele'.\n");
+  printf("\n");
+  printf("    8  3  0\n");
+  printf("       1       1     5     6\n");
+  printf("       2       5     1     3\n");
+  printf("       3       2     6     8\n");
+  printf("       4       6     2     1\n");
+  printf("       5       7     3     4\n");
+  printf("       6       3     7     5\n");
+  printf("       7       8     4     2\n");
+  printf("       8       4     8     7\n");
+  printf("    # Generated by triangle -pcBev box\n\n");
+  printf("  Here is the edge file for the triangulation, `box.1.edge'.\n\n");
+  printf("    16  0\n");
+  printf("       1   1  5\n");
+  printf("       2   5  6\n");
+  printf("       3   6  1\n");
+  printf("       4   1  3\n");
+  printf("       5   3  5\n");
+  printf("       6   2  6\n");
+  printf("       7   6  8\n");
+  printf("       8   8  2\n");
+  printf("       9   2  1\n");
+  printf("      10   7  3\n");
+  printf("      11   3  4\n");
+  printf("      12   4  7\n");
+  printf("      13   7  5\n");
+  printf("      14   8  4\n");
+  printf("      15   4  2\n");
+  printf("      16   8  7\n");
+  printf("    # Generated by triangle -pcBev box\n");
+  printf("\n");
+  printf(
+"  Here's a file `box.1.part' that partitions the mesh into four subdomains.\n"
+);
+  printf("\n");
+  printf("    8  4\n");
+  printf("       1    3\n");
+  printf("       2    3\n");
+  printf("       3    4\n");
+  printf("       4    4\n");
+  printf("       5    1\n");
+  printf("       6    1\n");
+  printf("       7    2\n");
+  printf("       8    2\n");
+  printf("    # Generated by slice -s4 box.1\n\n");
+  printf(
+"  Here's a file `box.1.adj' that represents the resulting adjacencies.\n");
+  printf("\n");
+  printf("    4\n");
+  printf("      9\n");
+  printf("      2\n");
+  printf("      2\n");
+  printf("      0\n");
+  printf("      2\n");
+  printf("      9\n");
+  printf("      0\n");
+  printf("      2\n");
+  printf("      2\n");
+  printf("      0\n");
+  printf("      9\n");
+  printf("      2\n");
+  printf("      0\n");
+  printf("      2\n");
+  printf("      2\n");
+  printf("      9\n");
+  printf("\n");
+  printf("Display Speed:\n");
+  printf("\n");
+  printf(
+"  It is worthwhile to note that .edge files typically plot and print twice\n"
+);
+  printf(
+"  as quickly as .ele files, because .ele files cause each internal edge to\n"
+);
+  printf(
+"  be drawn twice.  For the same reason, PostScript files created from edge\n"
+);
+  printf("  sets are smaller than those created from triangulations.\n\n");
+  printf("Show Me on the Web:\n\n");
+  printf(
+"  To see an illustrated, updated version of these instructions, check out\n");
+  printf("\n");
+  printf("    http://www.cs.cmu.edu/~quake/showme.html\n");
+  printf("\n");
+  printf("A Brief Plea:\n");
+  printf("\n");
+  printf(
+"  If you use Show Me (or Triangle), and especially if you use it to\n");
+  printf(
+"  accomplish real work, I would like very much to hear from you.  A short\n");
+  printf(
+"  letter or email (to jrs@cs.cmu.edu) describing how you use Show Me (and\n");
+  printf(
+"  its sister programs) will mean a lot to me.  The more people I know\n");
+  printf(
+"  are using my programs, the more easily I can justify spending time on\n");
+  printf(
+"  improvements, which in turn will benefit you.  Also, I can put you\n");
+  printf(
+"  on a list to receive email whenever new versions are available.\n");
+  printf("\n");
+  printf(
+"  If you use a PostScript file generated by Show Me in a publication,\n");
+  printf("  please include an acknowledgment as well.\n\n");
+  exit(0);
+}
+
+void set_filenames(filename, lowermeshnumber)
+char *filename;
+int lowermeshnumber;
+{
+  char numberstring[100];
+  int i;
+
+  for (i = 0; i < 2; i++) {
+    strcpy(nodefilename[i], filename);
+    strcpy(polyfilename[i], filename);
+    strcpy(elefilename[i], filename);
+    strcpy(edgefilename[i], filename);
+    strcpy(partfilename[i], filename);
+    strcpy(adjfilename[i], filename);
+    strcpy(vnodefilename[i], filename);
+    strcpy(vedgefilename[i], filename);
+
+    if (lowermeshnumber + i > 0) {
+      sprintf(numberstring, ".%d", lowermeshnumber + i);
+      strcat(nodefilename[i], numberstring);
+      strcat(polyfilename[i], numberstring);
+      strcat(elefilename[i], numberstring);
+      strcat(edgefilename[i], numberstring);
+      strcat(partfilename[i], numberstring);
+      strcat(adjfilename[i], numberstring);
+      strcat(vnodefilename[i], numberstring);
+      strcat(vedgefilename[i], numberstring);
+    }
+
+    strcat(nodefilename[i], ".node");
+    strcat(polyfilename[i], ".poly");
+    strcat(elefilename[i], ".ele");
+    strcat(edgefilename[i], ".edge");
+    strcat(partfilename[i], ".part");
+    strcat(adjfilename[i], ".adj");
+    strcat(vnodefilename[i], ".v.node");
+    strcat(vedgefilename[i], ".v.edge");
+  }
+}
+
+void parsecommandline(argc, argv)
+int argc;
+char **argv;
+{
+  int increment;
+  int meshnumber;
+  int i, j;
+
+  quiet = 0;
+  fillelem = 0;
+  line_width = 1;
+  bw_ps = 0;
+  start_image = ELE;
+  filename[0] = '\0';
+  for (i = 1; i < argc; i++) {
+    if (argv[i][0] == '-') {
+      for (j = 1; argv[i][j] != '\0'; j++) {
+        if (argv[i][j] == 'f') {
+          fillelem = 1;
+       }
+        if (argv[i][j] == 'w') {
+          if ((argv[i][j + 1] >= '1') && (argv[i][j + 1] <= '9')) {
+            line_width = 0;
+            while ((argv[i][j + 1] >= '0') && (argv[i][j + 1] <= '9')) {
+              j++;
+              line_width = line_width * 10 + (int) (argv[i][j] - '0');
+            }
+            if (line_width > 100) {
+              printf("Error:  Line width cannot exceed 100.\n");
+              line_width = 1;
+           }
+         }
+       }
+        if (argv[i][j] == 'b') {
+          bw_ps = 1;
+       }
+        if (argv[i][j] == 'Q') {
+          quiet = 1;
+       }
+        if ((argv[i][j] == 'h') || (argv[i][j] == 'H') ||
+            (argv[i][j] == '?')) {
+          info();
+       }
+      }
+    } else {
+      strcpy(filename, argv[i]);
+    }
+  }
+  if (filename[0] == '\0') {
+    syntax();
+  }
+  if (!strcmp(&filename[strlen(filename) - 5], ".node")) {
+    filename[strlen(filename) - 5] = '\0';
+    start_image = NODE;
+  }
+  if (!strcmp(&filename[strlen(filename) - 5], ".poly")) {
+    filename[strlen(filename) - 5] = '\0';
+    start_image = POLY;
+  }
+  if (!strcmp(&filename[strlen(filename) - 4], ".ele")) {
+    filename[strlen(filename) - 4] = '\0';
+    start_image = ELE;
+  }
+  if (!strcmp(&filename[strlen(filename) - 5], ".edge")) {
+    filename[strlen(filename) - 5] = '\0';
+    start_image = EDGE;
+  }
+  if (!strcmp(&filename[strlen(filename) - 5], ".part")) {
+    filename[strlen(filename) - 5] = '\0';
+    start_image = PART;
+  }
+  if (!strcmp(&filename[strlen(filename) - 4], ".adj")) {
+    filename[strlen(filename) - 4] = '\0';
+    start_image = ADJ;
+  }
+
+  increment = 0;
+  j = 1;
+  while (filename[j] != '\0') {
+    if ((filename[j] == '.') && (filename[j + 1] != '\0')) {
+      increment = j + 1;
+    }
+    j++;
+  }
+  meshnumber = 0;
+  if (increment > 0) {
+    j = increment;
+    do {
+      if ((filename[j] >= '0') && (filename[j] <= '9')) {
+        meshnumber = meshnumber * 10 + (int) (filename[j] - '0');
+      } else {
+        increment = 0;
+      }
+      j++;
+    } while (filename[j] != '\0');
+  }
+  if (increment > 0) {
+    filename[increment - 1] = '\0';
+  }
+
+  if (meshnumber == 0) {
+    start_inc = 0;
+    loweriteration = 0;
+  } else {
+    start_inc = 1;
+    loweriteration = meshnumber - 1;
+  }
+  set_filenames(filename, loweriteration);
+}
+
+void free_inc(inc)
+int inc;
+{
+  if (loaded[inc][NODE]) {
+    free(nodeptr[inc]);
+  }
+  if (loaded[inc][POLY]) {
+    if (polynodes[inc] > 0) {
+      free(polynodeptr[inc]);
+    }
+    free(polyedgeptr[inc]);
+    free(polyholeptr[inc]);
+  }
+  if (loaded[inc][ELE]) {
+    free(eleptr[inc]);
+  }
+  if (loaded[inc][PART]) {
+    free(partpart[inc]);
+    free(partcenter[inc]);
+    free(partshift[inc]);
+  }
+  if (loaded[inc][EDGE]) {
+    free(edgeptr[inc]);
+    free(normptr[inc]);
+  }
+  if (loaded[inc][ADJ]) {
+    free(adjptr[inc]);
+  }
+  if (loaded[inc][VORO]) {
+    free(vnodeptr[inc]);
+    free(vedgeptr[inc]);
+    free(vnormptr[inc]);
+  }
+}
+
+void move_inc(inc)
+int inc;
+{
+  int i;
+
+  free_inc(1 - inc);
+  for (i = 0; i < IMAGE_TYPES; i++) {
+    loaded[1 - inc][i] = loaded[inc][i];
+    loaded[inc][i] = 0;
+    xlo[1 - inc][i] = xlo[inc][i];
+    ylo[1 - inc][i] = ylo[inc][i];
+    xhi[1 - inc][i] = xhi[inc][i];
+    yhi[1 - inc][i] = yhi[inc][i];
+  }
+  nodes[1 - inc] = nodes[inc];
+  node_dim[1 - inc] = node_dim[inc];
+  nodeptr[1 - inc] = nodeptr[inc];
+  polynodes[1 - inc] = polynodes[inc];
+  poly_dim[1 - inc] = poly_dim[inc];
+  polyedges[1 - inc] = polyedges[inc];
+  polyholes[1 - inc] = polyholes[inc];
+  polynodeptr[1 - inc] = polynodeptr[inc];
+  polyedgeptr[1 - inc] = polyedgeptr[inc];
+  polyholeptr[1 - inc] = polyholeptr[inc];
+  elems[1 - inc] = elems[inc];
+  ele_corners[1 - inc] = ele_corners[inc];
+  eleptr[1 - inc] = eleptr[inc];
+  edges[1 - inc] = edges[inc];
+  edgeptr[1 - inc] = edgeptr[inc];
+  normptr[1 - inc] = normptr[inc];
+  subdomains[1 - inc] = subdomains[inc];
+  partpart[1 - inc] = partpart[inc];
+  partcenter[1 - inc] = partcenter[inc];
+  partshift[1 - inc] = partshift[inc];
+  adjsubdomains[1 - inc] = adjsubdomains[inc];
+  adjptr[1 - inc] = adjptr[inc];
+  vnodes[1 - inc] = vnodes[inc];
+  vnode_dim[1 - inc] = vnode_dim[inc];
+  vnodeptr[1 - inc] = vnodeptr[inc];
+  vedges[1 - inc] = vedges[inc];
+  vedgeptr[1 - inc] = vedgeptr[inc];
+  vnormptr[1 - inc] = vnormptr[inc];
+  firstnumber[1 - inc] = firstnumber[inc];
+  firstnumber[inc] = -1;
+}
+
+void unload_inc(inc)
+int inc;
+{
+  int i;
+
+  current_image = NOTHING;
+  for (i = 0; i < IMAGE_TYPES; i++) {
+    loaded[inc][i] = 0;
+    firstnumber[inc] = -1;
+  }
+}
+
+void showme_init()
+{
+  current_image = NOTHING;
+  current_inc = 0;
+  explosion = STARTEXPLOSION;
+  unload_inc(0);
+  unload_inc(1);
+}
+
+char *readline(string, infile, infilename)
+char *string;
+FILE *infile;
+char *infilename;
+{
+  char *result;
+
+  do {
+    result = fgets(string, INPUTLINESIZE, infile);
+    if (result == (char *) NULL) {
+      printf("  Error:  Unexpected end of file in %s.\n",
+             infilename);
+      exit(1);
+    }
+    while ((*result != '\0') && (*result != '#')
+           && (*result != '.') && (*result != '+') && (*result != '-')
+           && ((*result < '0') || (*result > '9'))) {
+      result++;
+    }
+  } while ((*result == '#') || (*result == '\0'));
+  return result;
+}
+
+char *findfield(string)
+char *string;
+{
+  char *result;
+
+  result = string;
+  while ((*result != '\0') && (*result != '#')
+         && (*result != ' ') && (*result != '\t')) {
+    result++;
+  }
+  while ((*result != '\0') && (*result != '#')
+         && (*result != '.') && (*result != '+') && (*result != '-')
+         && ((*result < '0') || (*result > '9'))) {
+    result++;
+  }
+  if (*result == '#') {
+    *result = '\0';
+  }
+  return result;
+}
+
+int load_node(fname, firstnumber, nodes, dim, ptr, xmin, ymin, xmax, ymax)
+char *fname;
+int *firstnumber;
+int *nodes;
+int *dim;
+REAL **ptr;
+REAL *xmin;
+REAL *ymin;
+REAL *xmax;
+REAL *ymax;
+{
+  FILE *infile;
+  char inputline[INPUTLINESIZE];
+  char *stringptr;
+  int extras;
+  int nodemarks;
+  int index;
+  int nodenumber;
+  int i, j;
+  int smallerr;
+  REAL x, y;
+
+  *xmin = *ymin = 0.0;
+  *xmax = *ymax = 1.0;
+  if (!quiet) {
+    printf("Opening %s.\n", fname);
+  }
+  infile = fopen(fname, "r");
+  if (infile == (FILE *) NULL) {
+    printf("  Error:  Cannot access file %s.\n", fname);
+    return 1;
+  }
+  stringptr = readline(inputline, infile, fname);
+  *nodes = (int) strtol (stringptr, &stringptr, 0);
+  if (*nodes < 3) {
+    printf("  Error:  %s contains %d points.\n", fname, *nodes);
+    return 1;
+  }
+  stringptr = findfield(stringptr);
+  if (*stringptr == '\0') {
+    *dim = 2;
+  } else {
+    *dim = (int) strtol (stringptr, &stringptr, 0);
+  }
+  if (*dim < 1) {
+    printf("  Error:  %s has dimensionality %d.\n", fname, *dim);
+    return 1;
+  }
+  if (*dim != 2) {
+    printf("  I only understand two-dimensional meshes.\n");
+    return 1;
+  }
+  stringptr = findfield(stringptr);
+  if (*stringptr == '\0') {
+    extras = 0;
+  } else {
+    extras = (int) strtol (stringptr, &stringptr, 0);
+  }
+  if (extras < 0) {
+    printf("  Error:  %s has negative value for number of attributes.\n",
+           fname);
+    return 1;
+  }
+  stringptr = findfield(stringptr);
+  if (*stringptr == '\0') {
+    nodemarks = 0;
+  } else {
+    nodemarks = (int) strtol (stringptr, &stringptr, 0);
+  }
+  if (nodemarks < 0) {
+    printf("  Warning:  %s has negative value for number of point markers.\n",
+           fname);
+  }
+  if (nodemarks > 1) {
+    printf(
+   "  Warning:  %s has value greater than one for number of point markers.\n",
+           fname);
+  }
+  *ptr = (REAL *) malloc((*nodes + 1) * *dim * sizeof(REAL));
+  if (*ptr == (REAL *) NULL) {
+    printf("  Out of memory.\n");
+    return 1;
+  }
+  index = *dim;
+  smallerr = 1;
+  for (i = 0; i < *nodes; i++) {
+    stringptr = readline(inputline, infile, fname);
+    nodenumber = (int) strtol (stringptr, &stringptr, 0);
+    if ((i == 0) && (*firstnumber == -1)) {
+      if (nodenumber == 0) {
+        *firstnumber = 0;
+      } else {
+        *firstnumber = 1;
+      }
+    }
+    if ((nodenumber != *firstnumber + i) && (smallerr)) {
+      printf("  Warning:  Points in %s are not numbered correctly\n", fname);
+      printf("            (starting with point %d).\n", *firstnumber + i);
+      smallerr = 0;
+    }
+    for (j = 0; j < *dim; j++) {
+      stringptr = findfield(stringptr);
+      if (*stringptr == '\0') {
+        printf("Error:  Point %d is missing a coordinate in %s.\n",
+               *firstnumber + i, fname);
+        free(*ptr);
+        return 1;
+      }
+      (*ptr)[index++] = (REAL) strtod(stringptr, &stringptr);
+    }
+  }
+  fclose(infile);
+  index = *dim;
+  *xmin = *xmax = (*ptr)[index];
+  *ymin = *ymax = (*ptr)[index + 1];
+  for (i = 2; i <= *nodes; i++) {
+    index += *dim;
+    x = (*ptr)[index];
+    y = (*ptr)[index + 1];
+    if (x < *xmin) {
+      *xmin = x;
+    }
+    if (y < *ymin) {
+      *ymin = y;
+    }
+    if (x > *xmax) {
+      *xmax = x;
+    }
+    if (y > *ymax) {
+      *ymax = y;
+    }
+  }
+  if (*xmin == *xmax) {
+    *xmin -= 0.5;
+    *xmax += 0.5;
+  }
+  if (*ymin == *ymax) {
+    *ymin -= 0.5;
+    *ymax += 0.5;
+  }
+  return 0;
+}
+
+int load_poly(inc, fname, firstnumber, pnodes, dim, edges, holes, nodeptr,
+              edgeptr, holeptr, xmin, ymin, xmax, ymax)
+int inc;
+char *fname;
+int *firstnumber;
+int *pnodes;
+int *dim;
+int *edges;
+int *holes;
+REAL **nodeptr;
+int **edgeptr;
+REAL **holeptr;
+REAL *xmin;
+REAL *ymin;
+REAL *xmax;
+REAL *ymax;
+{
+  FILE *infile;
+  char inputline[INPUTLINESIZE];
+  char *stringptr;
+  int extras;
+  int nodemarks;
+  int segmentmarks;
+  int index;
+  int nodenumber, edgenumber, holenumber;
+  int maxnode;
+  int i, j;
+  int smallerr;
+  REAL x, y;
+
+  if (!quiet) {
+    printf("Opening %s.\n", fname);
+  }
+  infile = fopen(fname, "r");
+  if (infile == (FILE *) NULL) {
+    printf("  Error:  Cannot access file %s.\n", fname);
+    return 1;
+  }
+  stringptr = readline(inputline, infile, fname);
+  *pnodes = (int) strtol (stringptr, &stringptr, 0);
+  if (*pnodes == 0) {
+    if (!loaded[inc][NODE]) {
+      if (load_image(inc, NODE)) {
+        return 1;
+      }
+    }
+    maxnode = nodes[inc];
+    *xmin = xlo[inc][NODE];
+    *ymin = ylo[inc][NODE];
+    *xmax = xhi[inc][NODE];
+    *ymax = yhi[inc][NODE];
+  } else {
+    if (*pnodes < 1) {
+      printf("  Error:  %s contains %d points.\n", fname, *pnodes);
+      return 1;
+    }
+    maxnode = *pnodes;
+  }
+  stringptr = findfield(stringptr);
+  if (*stringptr == '\0') {
+    *dim = 2;
+  } else {
+    *dim = (int) strtol (stringptr, &stringptr, 0);
+  }
+  if (*dim < 1) {
+    printf("  Error:  %s has dimensionality %d.\n", fname, *dim);
+    return 1;
+  }
+  if (*dim != 2) {
+    printf("  I only understand two-dimensional meshes.\n");
+    return 1;
+  }
+  stringptr = findfield(stringptr);
+  if (*stringptr == '\0') {
+    extras = 0;
+  } else {
+    extras = (int) strtol (stringptr, &stringptr, 0);
+  }
+  if (extras < 0) {
+    printf("  Error:  %s has negative value for number of attributes.\n",
+           fname);
+    return 1;
+  }
+  stringptr = findfield(stringptr);
+  if (*stringptr == '\0') {
+    nodemarks = 0;
+  } else {
+    nodemarks = (int) strtol (stringptr, &stringptr, 0);
+  }
+  if (nodemarks < 0) {
+    printf("  Warning:  %s has negative value for number of point markers.\n",
+           fname);
+  }
+  if (nodemarks > 1) {
+    printf(
+   "  Warning:  %s has value greater than one for number of point markers.\n",
+           fname);
+  }
+  if (*pnodes > 0) {
+    *nodeptr = (REAL *) malloc((*pnodes + 1) * *dim * sizeof(REAL));
+    if (*nodeptr == (REAL *) NULL) {
+      printf("  Out of memory.\n");
+      return 1;
+    }
+    index = *dim;
+    smallerr = 1;
+    for (i = 0; i < *pnodes; i++) {
+      stringptr = readline(inputline, infile, fname);
+      nodenumber = (int) strtol (stringptr, &stringptr, 0);
+      if ((i == 0) && (*firstnumber == -1)) {
+        if (nodenumber == 0) {
+          *firstnumber = 0;
+        } else {
+          *firstnumber = 1;
+        }
+      }
+      if ((nodenumber != *firstnumber + i) && (smallerr)) {
+        printf("  Warning:  Points in %s are not numbered correctly.\n",
+               fname);
+        printf("            (starting with point %d).\n", *firstnumber + i);
+        smallerr = 0;
+      }
+      for (j = 0; j < *dim; j++) {
+        stringptr = findfield(stringptr);
+        if (*stringptr == '\0') {
+          printf("Error:  Point %d is missing a coordinate in %s.\n",
+                 *firstnumber + i, fname);
+          free(*nodeptr);
+          return 1;
+        }
+        (*nodeptr)[index++] = (REAL) strtod(stringptr, &stringptr);
+      }
+    }
+  }
+  stringptr = readline(inputline, infile, fname);
+  *edges = (int) strtol (stringptr, &stringptr, 0);
+  if (*edges < 0) {
+    printf("  Error:  %s contains %d segments.\n", fname, *edges);
+    free(*nodeptr);
+    return 1;
+  }
+  stringptr = findfield(stringptr);
+  if (*stringptr == '\0') {
+    segmentmarks = 0;
+  } else {
+    segmentmarks = (int) strtol (stringptr, &stringptr, 0);
+  }
+  if (segmentmarks < 0) {
+    printf("  Error:  %s has negative value for number of segment markers.\n",
+           fname);
+    free(*nodeptr);
+    return 1;
+  }
+  if (segmentmarks > 1) {
+    printf(
+   "  Error:  %s has value greater than one for number of segment markers.\n",
+           fname);
+    free(*nodeptr);
+    return 1;
+  }
+  *edgeptr = (int *) malloc(((*edges + 1) << 1) * sizeof(int));
+  if (*edgeptr == (int *) NULL) {
+    printf("  Out of memory.\n");
+    free(*nodeptr);
+    return 1;
+  }
+  index = 2;
+  smallerr = 1;
+  for (i = *firstnumber; i < *firstnumber + *edges; i++) {
+    stringptr = readline(inputline, infile, fname);
+    edgenumber = (int) strtol (stringptr, &stringptr, 0);
+    if ((edgenumber != i) && (smallerr)) {
+      printf("  Warning:  Segments in %s are not numbered correctly.\n",
+             fname);
+      printf("            (starting with segment %d).\n", i);
+      smallerr = 0;
+    }
+    stringptr = findfield(stringptr);
+    if (*stringptr == '\0') {
+      printf("Error:  Segment %d is missing its endpoints in %s.\n", i, fname);
+      free(*nodeptr);
+      free(*edgeptr);
+      return 1;
+    }
+    (*edgeptr)[index] = (int) strtol (stringptr, &stringptr, 0) + 1 -
+                        *firstnumber;
+    if (((*edgeptr)[index] < 1) || ((*edgeptr)[index] > maxnode)) {
+      printf("Error:  Segment %d has invalid endpoint in %s.\n", i, fname);
+      return 1;
+    }
+    stringptr = findfield(stringptr);
+    if (*stringptr == '\0') {
+      printf("Error:  Segment %d is missing an endpoint in %s.\n", i, fname);
+      free(*nodeptr);
+      free(*edgeptr);
+      return 1;
+    }
+    (*edgeptr)[index + 1] = (int) strtol (stringptr, &stringptr, 0) + 1 -
+                            *firstnumber;
+    if (((*edgeptr)[index + 1] < 1) || ((*edgeptr)[index + 1] > maxnode)) {
+      printf("Error:  Segment %d has invalid endpoint in %s.\n", i, fname);
+      return 1;
+    }
+    index += 2;
+  }
+  stringptr = readline(inputline, infile, fname);
+  *holes = (int) strtol (stringptr, &stringptr, 0);
+  if (*holes < 0) {
+    printf("  Error:  %s contains %d holes.\n", fname, *holes);
+    free(*nodeptr);
+    free(*edgeptr);
+    return 1;
+  }
+  *holeptr = (REAL *) malloc((*holes + 1) * *dim * sizeof(REAL));
+  if (*holeptr == (REAL *) NULL) {
+    printf("  Out of memory.\n");
+    free(*nodeptr);
+    free(*edgeptr);
+    return 1;
+  }
+  index = *dim;
+  smallerr = 1;
+  for (i = *firstnumber; i < *firstnumber + *holes; i++) {
+    stringptr = readline(inputline, infile, fname);
+    holenumber = (int) strtol (stringptr, &stringptr, 0);
+    if ((holenumber != i) && (smallerr)) {
+      printf("  Warning:  Holes in %s are not numbered correctly.\n", fname);
+      printf("            (starting with hole %d).\n", i);
+      smallerr = 0;
+    }
+    for (j = 0; j < *dim; j++) {
+      stringptr = findfield(stringptr);
+      if (*stringptr == '\0') {
+        printf("Error:  Hole %d is missing a coordinate in %s.\n", i,
+               fname);
+        free(*nodeptr);
+        free(*edgeptr);
+        free(*holeptr);
+        return 1;
+      }
+      (*holeptr)[index++] = (REAL) strtod(stringptr, &stringptr);
+    }
+  }
+  fclose(infile);
+  if (*pnodes > 0) {
+    index = *dim;
+    *xmin = *xmax = (*nodeptr)[index];
+    *ymin = *ymax = (*nodeptr)[index + 1];
+    for (i = 2; i <= *pnodes; i++) {
+      index += *dim;
+      x = (*nodeptr)[index];
+      y = (*nodeptr)[index + 1];
+      if (x < *xmin) {
+        *xmin = x;
+      }
+      if (y < *ymin) {
+        *ymin = y;
+      }
+      if (x > *xmax) {
+        *xmax = x;
+      }
+      if (y > *ymax) {
+        *ymax = y;
+      }
+    }
+  }
+  index = *dim;
+  for (i = 1; i <= *holes; i++) {
+    x = (*holeptr)[index];
+    y = (*holeptr)[index + 1];
+    if (x < *xmin) {
+      *xmin = x;
+    }
+    if (y < *ymin) {
+      *ymin = y;
+    }
+    if (x > *xmax) {
+      *xmax = x;
+    }
+    if (y > *ymax) {
+      *ymax = y;
+    }
+    index += *dim;
+  }
+  return 0;
+}
+
+int load_ele(fname, firstnumber, nodes, elems, corners, ptr)
+char *fname;
+int firstnumber;
+int nodes;
+int *elems;
+int *corners;
+int **ptr;
+{
+  FILE *infile;
+  char inputline[INPUTLINESIZE];
+  char *stringptr;
+  int extras;
+  int index;
+  int elemnumber;
+  int i, j;
+  int smallerr;
+
+  if (!quiet) {
+    printf("Opening %s.\n", fname);
+  }
+  infile = fopen(fname, "r");
+  if (infile == (FILE *) NULL) {
+    printf("  Error:  Cannot access file %s.\n", fname);
+    return 1;
+  }
+  stringptr = readline(inputline, infile, fname);
+  *elems = (int) strtol (stringptr, &stringptr, 0);
+  if (*elems < 1) {
+    printf("  Error:  %s contains %d triangles.\n", fname, *elems);
+    return 1;
+  }
+  stringptr = findfield(stringptr);
+  if (*stringptr == '\0') {
+    *corners = 3;
+  } else {
+    *corners = (int) strtol (stringptr, &stringptr, 0);
+  }
+  if (*corners < 3) {
+    printf("  Error:  Triangles in %s have only %d corners.\n", fname,
+           *corners);
+    return 1;
+  }
+  stringptr = findfield(stringptr);
+  if (*stringptr == '\0') {
+    extras = 0;
+  } else {
+    extras = (int) strtol (stringptr, &stringptr, 0);
+  }
+  if (extras < 0) {
+    printf("  Error:  %s has negative value for extra fields.\n", fname);
+    return 1;
+  }
+  *ptr = (int *) malloc((*elems + 1) * 3 * sizeof(int));
+  if (*ptr == (int *) NULL) {
+    printf("  Out of memory.\n");
+    return 1;
+  }
+  index = 3;
+  smallerr = 1;
+  for (i = firstnumber; i < firstnumber + *elems; i++) {
+    stringptr = readline(inputline, infile, fname);
+    elemnumber = (int) strtol (stringptr, &stringptr, 0);
+    if ((elemnumber != i) && (smallerr)) {
+      printf("  Warning:  Triangles in %s are not numbered correctly.\n",
+             fname);
+      printf("            (starting with triangle %d).\n", i);
+      smallerr = 0;
+    }
+    for (j = 0; j < 3; j++) {
+      stringptr = findfield(stringptr);
+      if (*stringptr == '\0') {
+        printf("Error:  Triangle %d is missing a corner in %s.\n", i, fname);
+        free(*ptr);
+        return 1;
+      }
+      (*ptr)[index] = (int) strtol (stringptr, &stringptr, 0) + 1 -
+                      firstnumber;
+      if (((*ptr)[index] < 1) || ((*ptr)[index] > nodes)) {
+        printf("Error:  Triangle %d has invalid corner in %s.\n", i, fname);
+        return 1;
+      }
+      index++;
+    }
+  }
+  fclose(infile);
+  return 0;
+}
+
+int load_edge(fname, firstnumber, nodes, edges, edgeptr, normptr)
+char *fname;
+int firstnumber;
+int nodes;
+int *edges;
+int **edgeptr;
+REAL **normptr;
+{
+  FILE *infile;
+  char inputline[INPUTLINESIZE];
+  char *stringptr;
+  int index;
+  int edgenumber;
+  int edgemarks;
+  int i;
+  int smallerr;
+
+  if (!quiet) {
+    printf("Opening %s.\n", fname);
+  }
+  infile = fopen(fname, "r");
+    if (infile == (FILE *) NULL) {
+      printf("  Error:  Cannot access file %s.\n", fname);
+      return 1;
+    }
+  stringptr = readline(inputline, infile, fname);
+  *edges = (int) strtol (stringptr, &stringptr, 0);
+  if (*edges < 1) {
+    printf("  Error:  %s contains %d edges.\n", fname, *edges);
+    return 1;
+  }
+  stringptr = findfield(stringptr);
+  if (*stringptr == '\0') {
+    edgemarks = 0;
+  } else {
+    edgemarks = (int) strtol (stringptr, &stringptr, 0);
+  }
+  if (edgemarks < 0) {
+    printf("  Error:  %s has negative value for number of edge markers.\n",
+           fname);
+    return 1;
+  }
+  if (edgemarks > 1) {
+    printf(
+   "  Error:  %s has value greater than one for number of edge markers.\n",
+           fname);
+    return 1;
+  }
+  *edgeptr = (int *) malloc(((*edges + 1) << 1) * sizeof(int));
+  if (*edgeptr == (int *) NULL) {
+    printf("  Out of memory.\n");
+    return 1;
+  }
+  *normptr = (REAL *) malloc(((*edges + 1) << 1) * sizeof(REAL));
+  if (*normptr == (REAL *) NULL) {
+    printf("  Out of memory.\n");
+    free(*edgeptr);
+    return 1;
+  }
+  index = 2;
+  smallerr = 1;
+  for (i = firstnumber; i < firstnumber + *edges; i++) {
+    stringptr = readline(inputline, infile, fname);
+    edgenumber = (int) strtol (stringptr, &stringptr, 0);
+    if ((edgenumber != i) && (smallerr)) {
+      printf("  Warning:  Edges in %s are not numbered correctly.\n", fname);
+      printf("            (starting with edge %d).\n", i);
+      smallerr = 0;
+    }
+    stringptr = findfield(stringptr);
+    if (*stringptr == '\0') {
+      printf("Error:  Edge %d is missing its endpoints in %s.\n", i, fname);
+      free(*edgeptr);
+      free(*normptr);
+      return 1;
+    }
+    (*edgeptr)[index] = (int) strtol (stringptr, &stringptr, 0) + 1 -
+                        firstnumber;
+    if (((*edgeptr)[index] < 1) || ((*edgeptr)[index] > nodes)) {
+      printf("Error:  Edge %d has invalid endpoint in %s.\n", i, fname);
+      return 1;
+    }
+    stringptr = findfield(stringptr);
+    if (*stringptr == '\0') {
+      printf("Error:  Edge %d is missing an endpoint in %s.\n", i, fname);
+      free(*edgeptr);
+      free(*normptr);
+      return 1;
+    }
+    (*edgeptr)[index + 1] = (int) strtol (stringptr, &stringptr, 0);
+    if ((*edgeptr)[index + 1] == -1) {
+      stringptr = findfield(stringptr);
+      if (*stringptr == '\0') {
+        printf("Error:  Edge %d is missing its direction in %s.\n", i, fname);
+        free(*edgeptr);
+        free(*normptr);
+        return 1;
+      }
+      (*normptr)[index] = (REAL) strtod(stringptr, &stringptr);
+      stringptr = findfield(stringptr);
+      if (*stringptr == '\0') {
+        printf("Error:  Edge %d is missing a direction coordinate in %s.\n",
+               i, fname);
+        free(*edgeptr);
+        free(*normptr);
+        return 1;
+      }
+      (*normptr)[index + 1] = (REAL) strtod(stringptr, &stringptr);
+    } else {
+      (*edgeptr)[index + 1] += 1 - firstnumber;
+      if (((*edgeptr)[index + 1] < 1) || ((*edgeptr)[index + 1] > nodes)) {
+        printf("Error:  Edge %d has invalid endpoint in %s.\n", i, fname);
+        return 1;
+      }
+    }
+    index += 2;
+  }
+  fclose(infile);
+  return 0;
+}
+
+int load_part(fname, dim, firstnumber, elems, nodeptr, eleptr, parts,
+              partition, partcenter, partshift)
+char *fname;
+int dim;
+int firstnumber;
+int elems;
+REAL *nodeptr;
+int *eleptr;
+int *parts;
+int **partition;
+REAL **partcenter;
+REAL **partshift;
+{
+  FILE *infile;
+  char inputline[INPUTLINESIZE];
+  char *stringptr;
+  int partelems;
+  int index;
+  int elemnumber;
+  int i, j;
+  int smallerr;
+  int *partsize;
+
+  if (!quiet) {
+    printf("Opening %s.\n", fname);
+  }
+  infile = fopen(fname, "r");
+  if (infile == (FILE *) NULL) {
+    printf("  Error:  Cannot access file %s.\n", fname);
+    return 1;
+  }
+  stringptr = readline(inputline, infile, fname);
+  partelems = (int) strtol (stringptr, &stringptr, 0);
+  if (partelems != elems) {
+    printf(
+      "  Error:  .ele and .part files do not agree on number of triangles.\n");
+    return 1;
+  }
+  stringptr = findfield(stringptr);
+  if (*stringptr == '\0') {
+    *parts = 1;
+  } else {
+    *parts = (int) strtol (stringptr, &stringptr, 0);
+  }
+  if (*parts < 1) {
+    printf("  Error:  %s specifies %d subdomains.\n", fname, *parts);
+    return 1;
+  }
+  *partition = (int *) malloc((elems + 1) * sizeof(int));
+  if (*partition == (int *) NULL) {
+    printf("  Out of memory.\n");
+    return 1;
+  }
+  smallerr = 1;
+  for (i = firstnumber; i < firstnumber + partelems; i++) {
+    stringptr = readline(inputline, infile, fname);
+    elemnumber = (int) strtol (stringptr, &stringptr, 0);
+    if ((elemnumber != i) && (smallerr)) {
+      printf("  Warning:  Triangles in %s are not numbered correctly.\n",
+             fname);
+      printf("            (starting with triangle %d).\n", i);
+      smallerr = 0;
+    }
+    stringptr = findfield(stringptr);
+    if (*stringptr == '\0') {
+      printf("Error:  Triangle %d has no subdomain in %s.\n", i, fname);
+      free(*partition);
+      return 1;
+    }
+    (*partition)[i] = (int) strtol (stringptr, &stringptr, 0) - firstnumber;
+    if (((*partition)[i] >= *parts) || ((*partition)[i] < 0)) {
+      printf("  Error:  Triangle %d of %s has an invalid subdomain.\n",
+             i, fname);
+      free(*partition);
+      return 1;
+    }
+  }
+  fclose(infile);
+  *partcenter = (REAL *) malloc(((*parts + 1) << 1) * sizeof(REAL));
+  if (*partcenter == (REAL *) NULL) {
+    printf("Error:  Out of memory.\n");
+    free(*partition);
+    return 1;
+  }
+  *partshift = (REAL *) malloc((*parts << 1) * sizeof(REAL));
+  if (*partshift == (REAL *) NULL) {
+    printf("Error:  Out of memory.\n");
+    free(*partition);
+    free(*partcenter);
+    return 1;
+  }
+  partsize = (int *) malloc((*parts + 1) * sizeof(int));
+  if (partsize == (int *) NULL) {
+    printf("Error:  Out of memory.\n");
+    free(*partition);
+    free(*partcenter);
+    free(*partshift);
+    return 1;
+  }
+  index = 3;
+  for (i = 0; i <= *parts; i++) {
+    partsize[i] = 0;
+    (*partcenter)[i << 1] = 0.0;
+    (*partcenter)[(i << 1) + 1] = 0.0;
+  }
+  for (i = 1; i <= elems; i++) {
+    partsize[(*partition)[i]] += 3;
+    for (j = 0; j < 3; j++) {
+      (*partcenter)[(*partition)[i] << 1] +=
+                nodeptr[eleptr[index] * dim];
+      (*partcenter)[((*partition)[i] << 1) + 1] +=
+                nodeptr[eleptr[index++] * dim + 1];
+    }
+  }
+  for (i = 0; i < *parts; i++) {
+    (*partcenter)[i << 1] /= (REAL) partsize[i];
+    (*partcenter)[(i << 1) + 1] /= (REAL) partsize[i];
+    (*partcenter)[*parts << 1] += (*partcenter)[i << 1];
+    (*partcenter)[(*parts << 1) + 1] += (*partcenter)[(i << 1) + 1];
+  }
+  (*partcenter)[*parts << 1] /= (REAL) *parts;
+  (*partcenter)[(*parts << 1) + 1] /= (REAL) *parts;
+  free(partsize);
+  return 0;
+}
+
+int load_adj(fname, subdomains, ptr)
+char *fname;
+int *subdomains;
+int **ptr;
+{
+  FILE *infile;
+  char inputline[INPUTLINESIZE];
+  char *stringptr;
+  int i, j;
+
+  if (!quiet) {
+    printf("Opening %s.\n", fname);
+  }
+  infile = fopen(fname, "r");
+  if (infile == (FILE *) NULL) {
+    printf("  Error:  Cannot access file %s.\n", fname);
+    return 1;
+  }
+  stringptr = readline(inputline, infile, fname);
+  *subdomains = (int) strtol (stringptr, &stringptr, 0);
+  if (*subdomains < 1) {
+    printf("  Error:  %s contains %d subdomains.\n", fname, *subdomains);
+    return 1;
+  }
+  *ptr = (int *) malloc(*subdomains * *subdomains * sizeof(int));
+  if (*ptr == (int *) NULL) {
+    printf("  Out of memory.\n");
+    return 1;
+  }
+  for (i = 0; i < *subdomains; i++) {
+    for (j = 0; j < *subdomains; j++) {
+      stringptr = readline(inputline, infile, fname);
+      (*ptr)[i * *subdomains + j] = (int) strtol (stringptr, &stringptr, 0);
+    }
+  }
+  return 0;
+}
+
+void findpartshift(parts, explosion, partcenter, partshift)
+int parts;
+REAL explosion;
+REAL *partcenter;
+REAL *partshift;
+{
+  int i;
+
+  for (i = 0; i < parts; i++) {
+    partshift[i << 1] = explosion *
+          (partcenter[i << 1] - partcenter[parts << 1]);
+    partshift[(i << 1) + 1] = explosion *
+          (partcenter[(i << 1) + 1] - partcenter[(parts << 1) + 1]);
+  }
+}
+
+int load_image(inc, image)
+int inc;
+int image;
+{
+  int error;
+
+  switch (image) {
+    case NODE:
+      error = load_node(nodefilename[inc], &firstnumber[inc], &nodes[inc],
+                        &node_dim[inc], &nodeptr[inc], &xlo[inc][NODE],
+                        &ylo[inc][NODE], &xhi[inc][NODE], &yhi[inc][NODE]);
+      break;
+    case POLY:
+      error = load_poly(inc, polyfilename[inc], &firstnumber[inc],
+                        &polynodes[inc], &poly_dim[inc], &polyedges[inc],
+                        &polyholes[inc], &polynodeptr[inc], &polyedgeptr[inc],
+                        &polyholeptr[inc],
+                        &xlo[inc][POLY], &ylo[inc][POLY],
+                        &xhi[inc][POLY], &yhi[inc][POLY]);
+      break;
+    case ELE:
+      error = load_ele(elefilename[inc], firstnumber[inc], nodes[inc],
+                       &elems[inc], &ele_corners[inc], &eleptr[inc]);
+      xlo[inc][ELE] = xlo[inc][NODE];
+      ylo[inc][ELE] = ylo[inc][NODE];
+      xhi[inc][ELE] = xhi[inc][NODE];
+      yhi[inc][ELE] = yhi[inc][NODE];
+      break;
+    case EDGE:
+      error = load_edge(edgefilename[inc], firstnumber[inc], nodes[inc],
+                        &edges[inc], &edgeptr[inc], &normptr[inc]);
+      xlo[inc][EDGE] = xlo[inc][NODE];
+      ylo[inc][EDGE] = ylo[inc][NODE];
+      xhi[inc][EDGE] = xhi[inc][NODE];
+      yhi[inc][EDGE] = yhi[inc][NODE];
+      break;
+    case PART:
+      error = load_part(partfilename[inc], node_dim[inc], firstnumber[inc],
+                        elems[inc], nodeptr[inc], eleptr[inc],
+                        &subdomains[inc], &partpart[inc], &partcenter[inc],
+                        &partshift[inc]);
+      if (!error) {
+        findpartshift(subdomains[inc], explosion, partcenter[inc],
+                      partshift[inc]);
+      }
+      xlo[inc][PART] = xlo[inc][NODE];
+      ylo[inc][PART] = ylo[inc][NODE];
+      xhi[inc][PART] = xhi[inc][NODE];
+      yhi[inc][PART] = yhi[inc][NODE];
+      break;
+    case ADJ:
+      error = load_adj(adjfilename[inc], &adjsubdomains[inc], &adjptr[inc]);
+      xlo[inc][ADJ] = xlo[inc][NODE];
+      ylo[inc][ADJ] = ylo[inc][NODE];
+      xhi[inc][ADJ] = xhi[inc][NODE];
+      yhi[inc][ADJ] = yhi[inc][NODE];
+      break;
+    case VORO:
+      error = load_node(vnodefilename[inc], &firstnumber[inc], &vnodes[inc],
+                        &vnode_dim[inc], &vnodeptr[inc], &xlo[inc][VORO],
+                        &ylo[inc][VORO], &xhi[inc][VORO], &yhi[inc][VORO]);
+      if (!error) {
+        error = load_edge(vedgefilename[inc], firstnumber[inc], vnodes[inc],
+                          &vedges[inc], &vedgeptr[inc], &vnormptr[inc]);
+      }
+      break;
+    default:
+      error = 1;
+  }
+  if (!error) {
+    loaded[inc][image] = 1;
+  }
+  return error;
+}
+
+void choose_image(inc, image)
+int inc;
+int image;
+{
+  if (!loaded[inc][image]) {
+    if ((image == ELE) || (image == EDGE) || (image == PART)
+        || (image == ADJ)) {
+      if (!loaded[inc][NODE]) {
+        if (load_image(inc, NODE)) {
+          return;
+        }
+      }
+    }
+    if ((image == PART) || (image == ADJ)) {
+      if (!loaded[inc][ELE]) {
+        if (load_image(inc, ELE)) {
+          return;
+        }
+      }
+    }
+    if (image == ADJ) {
+      if (!loaded[inc][PART]) {
+        if (load_image(inc, PART)) {
+          return;
+        }
+      }
+    }
+    if (load_image(inc, image)) {
+      return;
+    }
+  }
+  current_inc = inc;
+  current_image = image;
+}
+
+Window make_button(name, x, y, width)
+char *name;
+int x;
+int y;
+int width;
+{
+  XSetWindowAttributes attr;
+  XSizeHints hints;
+  Window button;
+
+  attr.background_pixel = black;
+  attr.border_pixel = white;
+  attr.backing_store = NotUseful;
+  attr.event_mask = ExposureMask | ButtonReleaseMask | ButtonPressMask;
+  attr.bit_gravity = SouthWestGravity;
+  attr.win_gravity = SouthWestGravity;
+  attr.save_under = False;
+  button = XCreateWindow(display, mainwindow, x, y, width, BUTTONHEIGHT - 4,
+                         2, 0, InputOutput, CopyFromParent,
+                         CWBackPixel | CWBorderPixel | CWEventMask |
+                         CWBitGravity | CWWinGravity | CWBackingStore |
+                         CWSaveUnder, &attr);
+  hints.width = width;
+  hints.height = BUTTONHEIGHT - 4;
+  hints.min_width = 0;
+  hints.min_height = BUTTONHEIGHT - 4;
+  hints.max_width = width;
+  hints.max_height = BUTTONHEIGHT - 4;
+  hints.width_inc = 1;
+  hints.height_inc = 1;
+  hints.flags = PMinSize | PMaxSize | PSize | PResizeInc;
+  XSetStandardProperties(display, button, name, "showme", None, (char **) NULL,
+                         0, &hints);
+  return button;
+}
+
+void make_buttons(y)
+int y;
+{
+  int i;
+
+  for (i = 1; i >= 0; i--) {
+    nodewin[i] = make_button("node", 0, y + (1 - i) * BUTTONHEIGHT, 42);
+    XMapWindow(display, nodewin[i]);
+    polywin[i] = make_button("poly", 44, y + (1 - i) * BUTTONHEIGHT, 42);
+    XMapWindow(display, polywin[i]);
+    elewin[i] = make_button("ele", 88, y + (1 - i) * BUTTONHEIGHT, 33);
+    XMapWindow(display, elewin[i]);
+    edgewin[i] = make_button("edge", 123, y + (1 - i) * BUTTONHEIGHT, 42);
+    XMapWindow(display, edgewin[i]);
+    partwin[i] = make_button("part", 167, y + (1 - i) * BUTTONHEIGHT, 42);
+    XMapWindow(display, partwin[i]);
+    adjwin[i] = make_button("adj", 211, y + (1 - i) * BUTTONHEIGHT, 33);
+    XMapWindow(display, adjwin[i]);
+    voronoiwin[i] = make_button("voro", 246, y + (1 - i) * BUTTONHEIGHT, 42);
+    XMapWindow(display, voronoiwin[i]);
+  }
+  versionpluswin = make_button("    +", 290, y, 52);
+  XMapWindow(display, versionpluswin);
+  versionminuswin = make_button("    -", 290, y + BUTTONHEIGHT, 52);
+  XMapWindow(display, versionminuswin);
+
+  quitwin = make_button("Quit", 0, y + 2 * BUTTONHEIGHT, 42);
+  XMapWindow(display, quitwin);
+  leftwin = make_button("<", 44, y + 2 * BUTTONHEIGHT, 14);
+  XMapWindow(display, leftwin);
+  rightwin = make_button(">", 60, y + 2 * BUTTONHEIGHT, 14);
+  XMapWindow(display, rightwin);
+  upwin = make_button("^", 76, y + 2 * BUTTONHEIGHT, 14);
+  XMapWindow(display, upwin);
+  downwin = make_button("v", 92, y + 2 * BUTTONHEIGHT, 14);
+  XMapWindow(display, downwin);
+  resetwin = make_button("Reset", 108, y + 2 * BUTTONHEIGHT, 52);
+  XMapWindow(display, resetwin);
+  widthpluswin = make_button("Width+", 162, y + 2 * BUTTONHEIGHT, 61);
+  XMapWindow(display, widthpluswin);
+  widthminuswin = make_button("-", 225, y + 2 * BUTTONHEIGHT, 14);
+  XMapWindow(display, widthminuswin);
+  expwin = make_button("Exp", 241, y + 2 * BUTTONHEIGHT, 33);
+  XMapWindow(display, expwin);
+  exppluswin = make_button("+", 276, y + 2 * BUTTONHEIGHT, 14);
+  XMapWindow(display, exppluswin);
+  expminuswin = make_button("-", 292, y + 2 * BUTTONHEIGHT, 14);
+  XMapWindow(display, expminuswin);
+  fillwin = make_button("Fill", 308, y + 2 * BUTTONHEIGHT, 41);
+  XMapWindow(display, fillwin);
+  pswin = make_button("PS", 351, y + 2 * BUTTONHEIGHT, 24);
+  XMapWindow(display, pswin);
+  epswin = make_button("EPS", 377, y + 2 * BUTTONHEIGHT, 33);
+  XMapWindow(display, epswin);
+}
+
+void fill_button(button)
+Window button;
+{
+  int x, y;
+  unsigned int w, h, d, b;
+  Window rootw;
+
+  XGetGeometry(display, button, &rootw, &x, &y, &w, &h, &d, &b);
+  XFillRectangle(display, button, fontgc, 0, 0, w, h);
+}
+
+void draw_buttons()
+{
+  char numberstring[32];
+  char buttonstring[6];
+  int i;
+
+  for (i = 1; i >= 0; i--) {
+    if ((current_image == NODE) && (current_inc == i)) {
+      fill_button(nodewin[i]);
+      XDrawString(display, nodewin[i], blackfontgc, 2, 13, "node", 4);
+    } else {
+      XClearWindow(display, nodewin[i]);
+      XDrawString(display, nodewin[i], fontgc, 2, 13, "node", 4);
+    }
+    if ((current_image == POLY) && (current_inc == i)) {
+      fill_button(polywin[i]);
+      XDrawString(display, polywin[i], blackfontgc, 2, 13, "poly", 4);
+    } else {
+      XClearWindow(display, polywin[i]);
+      XDrawString(display, polywin[i], fontgc, 2, 13, "poly", 4);
+    }
+    if ((current_image == ELE) && (current_inc == i)) {
+      fill_button(elewin[i]);
+      XDrawString(display, elewin[i], blackfontgc, 2, 13, "ele", 3);
+    } else {
+      XClearWindow(display, elewin[i]);
+      XDrawString(display, elewin[i], fontgc, 2, 13, "ele", 3);
+    }
+    if ((current_image == EDGE) && (current_inc == i)) {
+      fill_button(edgewin[i]);
+      XDrawString(display, edgewin[i], blackfontgc, 2, 13, "edge", 4);
+    } else {
+      XClearWindow(display, edgewin[i]);
+      XDrawString(display, edgewin[i], fontgc, 2, 13, "edge", 4);
+    }
+    if ((current_image == PART) && (current_inc == i)) {
+      fill_button(partwin[i]);
+      XDrawString(display, partwin[i], blackfontgc, 2, 13, "part", 4);
+    } else {
+      XClearWindow(display, partwin[i]);
+      XDrawString(display, partwin[i], fontgc, 2, 13, "part", 4);
+    }
+    if ((current_image == ADJ) && (current_inc == i)) {
+      fill_button(adjwin[i]);
+      XDrawString(display, adjwin[i], blackfontgc, 2, 13, "adj", 3);
+    } else {
+      XClearWindow(display, adjwin[i]);
+      XDrawString(display, adjwin[i], fontgc, 2, 13, "adj", 3);
+    }
+    if ((current_image == VORO) && (current_inc == i)) {
+      fill_button(voronoiwin[i]);
+      XDrawString(display, voronoiwin[i], blackfontgc, 2, 13, "voro", 4);
+    } else {
+      XClearWindow(display, voronoiwin[i]);
+      XDrawString(display, voronoiwin[i], fontgc, 2, 13, "voro", 4);
+    }
+  }
+
+  XClearWindow(display, versionpluswin);
+  sprintf(numberstring, "%d", loweriteration + 1);
+  sprintf(buttonstring, "%-4.4s+", numberstring);
+  XDrawString(display, versionpluswin, fontgc, 2, 13, buttonstring, 5);
+  XClearWindow(display, versionminuswin);
+  sprintf(numberstring, "%d", loweriteration);
+  if (loweriteration == 0) {
+    sprintf(buttonstring, "%-4.4s", numberstring);
+  } else {
+    sprintf(buttonstring, "%-4.4s-", numberstring);
+  }
+  XDrawString(display, versionminuswin, fontgc, 2, 13, buttonstring, 5);
+
+  XClearWindow(display, quitwin);
+  XDrawString(display, quitwin, fontgc, 2, 13, "Quit", 4);
+  XClearWindow(display, leftwin);
+  XDrawString(display, leftwin, fontgc, 2, 13, "<", 1);
+  XClearWindow(display, rightwin);
+  XDrawString(display, rightwin, fontgc, 2, 13, ">", 1);
+  XClearWindow(display, upwin);
+  XDrawString(display, upwin, fontgc, 2, 13, "^", 1);
+  XClearWindow(display, downwin);
+  XDrawString(display, downwin, fontgc, 2, 13, "v", 1);
+  XClearWindow(display, resetwin);
+  XDrawString(display, resetwin, fontgc, 2, 13, "Reset", 6);
+  XClearWindow(display, widthpluswin);
+  if (line_width < 100) {
+    XDrawString(display, widthpluswin, fontgc, 2, 13, "Width+", 6);
+  } else {
+    XDrawString(display, widthpluswin, fontgc, 2, 13, "Width ", 6);
+  }
+  XClearWindow(display, widthminuswin);
+  if (line_width > 1) {
+    XDrawString(display, widthminuswin, fontgc, 2, 13, "-", 1);
+  }
+  XClearWindow(display, expwin);
+  XClearWindow(display, exppluswin);
+  XClearWindow(display, expminuswin);
+  XClearWindow(display, fillwin);
+  if (current_image == PART) {
+    if (explode) {
+      fill_button(expwin);
+      XDrawString(display, expwin, blackfontgc, 2, 13, "Exp", 3);
+    } else {
+      XDrawString(display, expwin, fontgc, 2, 13, "Exp", 3);
+    }
+    XDrawString(display, exppluswin, fontgc, 2, 13, "+", 1);
+    XDrawString(display, expminuswin, fontgc, 2, 13, "-", 1);
+    if (fillelem) {
+      fill_button(fillwin);
+      XDrawString(display, fillwin, blackfontgc, 2, 13, "Fill", 4);
+    } else {
+      XDrawString(display, fillwin, fontgc, 2, 13, "Fill", 4);
+    }
+  }
+  XClearWindow(display, pswin);
+  XDrawString(display, pswin, fontgc, 2, 13, "PS", 2);
+  XClearWindow(display, epswin);
+  XDrawString(display, epswin, fontgc, 2, 13, "EPS", 3);
+}
+
+void showme_window(argc, argv)
+int argc;
+char **argv;
+{
+  XSetWindowAttributes attr;
+  XSizeHints hints;
+  XGCValues fontvalues, linevalues;
+  XColor alloc_color, exact_color;
+  int i;
+
+  display = XOpenDisplay((char *) NULL);
+  if (!display) {
+    printf("Error:  Cannot open display.\n");
+    exit(1);
+  }
+  screen = DefaultScreen(display);
+  rootwindow = DefaultRootWindow(display);
+  black = BlackPixel(display, screen);
+  white = WhitePixel(display, screen);
+  windowdepth = DefaultDepth(display, screen);
+  rootmap = DefaultColormap(display, screen);
+  width = STARTWIDTH;
+  height = STARTHEIGHT;
+  attr.background_pixel = black;
+  attr.border_pixel = white;
+  attr.backing_store = NotUseful;
+  attr.event_mask = ExposureMask | ButtonReleaseMask | ButtonPressMask |
+                    StructureNotifyMask;
+  attr.bit_gravity = NorthWestGravity;
+  attr.win_gravity = NorthWestGravity;
+  attr.save_under = False;
+  mainwindow = XCreateWindow(display, rootwindow, 0, 0, width,
+                             height + PANELHEIGHT, 3, 0,
+                             InputOutput, CopyFromParent,
+                             CWBackPixel | CWBorderPixel | CWEventMask |
+                             CWBitGravity | CWWinGravity | CWBackingStore |
+                             CWSaveUnder, &attr);
+  hints.width = width;
+  hints.height = height + PANELHEIGHT;
+  hints.min_width = MINWIDTH;
+  hints.min_height = MINHEIGHT + PANELHEIGHT;
+  hints.width_inc = 1;
+  hints.height_inc = 1;
+  hints.flags = PMinSize | PSize | PResizeInc;
+  XSetStandardProperties(display, mainwindow, "Show Me", "showme", None,
+                         argv, argc, &hints);
+  XChangeProperty(display, mainwindow, XA_WM_CLASS, XA_STRING, 8,
+                  PropModeReplace, "showme\0Archimedes", 18);
+  XClearWindow(display, mainwindow);
+  XMapWindow(display, mainwindow);
+  if ((windowdepth > 1) &&
+      XAllocNamedColor(display, rootmap, "yellow", &alloc_color,
+                       &exact_color)) {
+    color = 1;
+    explode = bw_ps;
+    fontvalues.foreground = alloc_color.pixel;
+    linevalues.foreground = alloc_color.pixel;
+    showme_foreground = alloc_color.pixel;
+    for (i = 0; i < 64; i++) {
+      if (XAllocNamedColor(display, rootmap, colorname[i], &alloc_color,
+                           &rgb[i])) {
+        colors[i] = alloc_color.pixel;
+      } else {
+        colors[i] = white;
+        rgb[i].red = alloc_color.red;
+        rgb[i].green = alloc_color.green;
+        rgb[i].blue = alloc_color.blue;
+        if (!quiet) {
+          printf("Warning:  I could not allocate %s.\n", colorname[i]);
+        }
+      }
+    }
+  } else {
+    color = 0;
+    fillelem = 0;
+    explode = 1;
+    fontvalues.foreground = white;
+    linevalues.foreground = white;
+    showme_foreground = white;
+  }
+  font = XLoadQueryFont(display, "9x15");
+  fontvalues.background = black;
+  fontvalues.font = font->fid;
+  fontvalues.fill_style = FillSolid;
+  fontvalues.line_width = 2;
+  fontgc = XCreateGC(display, rootwindow, GCForeground | GCBackground |
+                      GCFont | GCLineWidth | GCFillStyle, &fontvalues);
+  fontvalues.foreground = black;
+  blackfontgc = XCreateGC(display, rootwindow, GCForeground | GCBackground |
+                         GCFont | GCLineWidth | GCFillStyle, &fontvalues);
+  linevalues.background = black;
+  linevalues.line_width = line_width;
+  linevalues.cap_style = CapRound;
+  linevalues.join_style = JoinRound;
+  linevalues.fill_style = FillSolid;
+  linegc = XCreateGC(display, rootwindow, GCForeground | GCBackground |
+                     GCLineWidth | GCCapStyle | GCJoinStyle | GCFillStyle,
+                     &linevalues);
+  trianglegc = XCreateGC(display, rootwindow, GCForeground | GCBackground |
+                         GCLineWidth | GCCapStyle | GCJoinStyle | GCFillStyle,
+                         &linevalues);
+  make_buttons(height);
+  XFlush(display);
+}
+
+void draw_node(nodes, dim, ptr, xscale, yscale, xoffset, yoffset)
+int nodes;
+int dim;
+REAL *ptr;
+REAL xscale;
+REAL yscale;
+REAL xoffset;
+REAL yoffset;
+{
+  int i;
+  int index;
+
+  index = dim;
+  for (i = 1; i <= nodes; i++) {
+    XFillRectangle(display, mainwindow, linegc,
+                   (int) (ptr[index] * xscale + xoffset) - (line_width >> 1),
+                   (int) (ptr[index + 1] * yscale + yoffset) -
+                         (line_width >> 1), line_width, line_width);
+    index += dim;
+  }
+}
+
+void draw_poly(nodes, dim, edges, holes, nodeptr, edgeptr, holeptr,
+               xscale, yscale, xoffset, yoffset)
+int nodes;
+int dim;
+int edges;
+int holes;
+REAL *nodeptr;
+int *edgeptr;
+REAL *holeptr;
+REAL xscale;
+REAL yscale;
+REAL xoffset;
+REAL yoffset;
+{
+  int i;
+  int index;
+  REAL *point1, *point2;
+  int x1, y1, x2, y2;
+
+  index = dim;
+  for (i = 1; i <= nodes; i++) {
+    XFillRectangle(display, mainwindow, linegc,
+                   (int) (nodeptr[index] * xscale + xoffset) -
+                         (line_width >> 1),
+                   (int) (nodeptr[index + 1] * yscale + yoffset) -
+                         (line_width >> 1), line_width, line_width);
+    index += dim;
+  }
+  index = 2;
+  for (i = 1; i <= edges; i++) {
+    point1 = &nodeptr[edgeptr[index++] * dim];
+    point2 = &nodeptr[edgeptr[index++] * dim];
+    XDrawLine(display, mainwindow, linegc,
+              (int) (point1[0] * xscale + xoffset),
+              (int) (point1[1] * yscale + yoffset),
+              (int) (point2[0] * xscale + xoffset),
+              (int) (point2[1] * yscale + yoffset));
+  }
+  index = dim;
+  if (color) {
+    XSetForeground(display, linegc, colors[0]);
+  }
+  for (i = 1; i <= holes; i++) {
+    x1 = (int) (holeptr[index] * xscale + xoffset) - 3;
+    y1 = (int) (holeptr[index + 1] * yscale + yoffset) - 3;
+    x2 = x1 + 6;
+    y2 = y1 + 6;
+    XDrawLine(display, mainwindow, linegc, x1, y1, x2, y2);
+    XDrawLine(display, mainwindow, linegc, x1, y2, x2, y1);
+    index += dim;
+  }
+  XSetForeground(display, linegc, showme_foreground);
+}
+
+void draw_ele(inc, elems, corners, ptr, partition, shift,
+              xscale, yscale, xoffset, yoffset)
+int inc;
+int elems;
+int corners;
+int *ptr;
+int *partition;
+REAL *shift;
+REAL xscale;
+REAL yscale;
+REAL xoffset;
+REAL yoffset;
+{
+  int i, j;
+  int index;
+  REAL shiftx, shifty;
+  REAL *prevpoint, *nowpoint;
+  XPoint *vertices;
+
+  if (color && fillelem && (partition != (int *) NULL)) {
+    vertices = (XPoint *) malloc(3 * sizeof(XPoint));
+    if (vertices == (XPoint *) NULL) {
+      printf("Error:  Out of memory.\n");
+      exit(1);
+    }
+  }
+  index = 3;
+  for (i = 1; i <= elems; i++) {
+    if ((partition != (int *) NULL) && explode) {
+      shiftx = shift[partition[i] << 1];
+      shifty = shift[(partition[i] << 1) + 1];
+    }
+    if (color && (partition != (int *) NULL)) {
+      if (fillelem) {
+        XSetForeground(display, trianglegc, colors[partition[i] & 63]);
+      } else {
+        XSetForeground(display, linegc, colors[partition[i] & 63]);
+      }
+    }
+    if (color && fillelem && (partition != (int *) NULL)) {
+      if ((partition != (int *) NULL) && explode) {
+        for (j = 0; j < 3; j++) {
+          nowpoint = &nodeptr[inc][ptr[index + j] * node_dim[inc]];
+          vertices[j].x = (nowpoint[0] + shiftx) * xscale + xoffset;
+          vertices[j].y = (nowpoint[1] + shifty) * yscale + yoffset;
+        }
+      } else {
+        for (j = 0; j < 3; j++) {
+          nowpoint = &nodeptr[inc][ptr[index + j] * node_dim[inc]];
+          vertices[j].x = nowpoint[0] * xscale + xoffset;
+          vertices[j].y = nowpoint[1] * yscale + yoffset;
+        }
+      }
+      XFillPolygon(display, mainwindow, trianglegc, vertices, 3,
+                   Convex, CoordModeOrigin);
+    }
+    prevpoint = &nodeptr[inc][ptr[index + 2] * node_dim[inc]];
+    if ((partition != (int *) NULL) && explode) {
+      for (j = 0; j < 3; j++) {
+        nowpoint = &nodeptr[inc][ptr[index++] * node_dim[inc]];
+        XDrawLine(display, mainwindow, linegc,
+                  (int) ((prevpoint[0] + shiftx) * xscale + xoffset),
+                  (int) ((prevpoint[1] + shifty) * yscale + yoffset),
+                  (int) ((nowpoint[0] + shiftx) * xscale + xoffset),
+                  (int) ((nowpoint[1] + shifty) * yscale + yoffset));
+        prevpoint = nowpoint;
+      }
+    } else {
+      for (j = 0; j < 3; j++) {
+        nowpoint = &nodeptr[inc][ptr[index++] * node_dim[inc]];
+        XDrawLine(display, mainwindow, linegc,
+                  (int) (prevpoint[0] * xscale + xoffset),
+                  (int) (prevpoint[1] * yscale + yoffset),
+                  (int) (nowpoint[0] * xscale + xoffset),
+                  (int) (nowpoint[1] * yscale + yoffset));
+        prevpoint = nowpoint;
+      }
+    }
+  }
+  if (color && fillelem && (partition != (int *) NULL)) {
+    free(vertices);
+  }
+  XSetForeground(display, linegc, showme_foreground);
+}
+
+void draw_edge(nodes, dim, edges, nodeptr, edgeptr, normptr,
+               xscale, yscale, xoffset, yoffset)
+int nodes;
+int dim;
+int edges;
+REAL *nodeptr;
+int *edgeptr;
+REAL *normptr;
+REAL xscale;
+REAL yscale;
+REAL xoffset;
+REAL yoffset;
+{
+  int i;
+  int index;
+  REAL *point1, *point2;
+  REAL normx, normy;
+  REAL normmult, normmultx, normmulty;
+  REAL windowxmin, windowymin, windowxmax, windowymax;
+
+  index = 2;
+  for (i = 1; i <= edges; i++) {
+    point1 = &nodeptr[edgeptr[index++] * dim];
+    if (edgeptr[index] == -1) {
+      normx = normptr[index - 1];
+      normy = normptr[index++];
+      normmultx = 0.0;
+      if (normx > 0) {
+        windowxmax = (width - 1 - xoffset) / xscale;
+        normmultx = (windowxmax - point1[0]) / normx;
+      } else if (normx < 0) {
+        windowxmin = -xoffset / xscale;
+        normmultx = (windowxmin - point1[0]) / normx;
+      }
+      normmulty = 0.0;
+      if (normy > 0) {
+        windowymax = -yoffset / yscale;
+        normmulty = (windowymax - point1[1]) / normy;
+      } else if (normy < 0) {
+        windowymin = (height - 1 - yoffset) / yscale;
+        normmulty = (windowymin - point1[1]) / normy;
+      }
+      if (normmultx == 0.0) {
+        normmult = normmulty;
+      } else if (normmulty == 0.0) {
+        normmult = normmultx;
+      } else if (normmultx < normmulty) {
+        normmult = normmultx;
+      } else {
+        normmult = normmulty;
+      }
+      if (normmult > 0.0) {
+        XDrawLine(display, mainwindow, linegc,
+                  (int) (point1[0] * xscale + xoffset),
+                  (int) (point1[1] * yscale + yoffset),
+                  (int) ((point1[0] + normmult * normx) * xscale + xoffset),
+                  (int) ((point1[1] + normmult * normy) * yscale + yoffset));
+      }
+    } else {
+      point2 = &nodeptr[edgeptr[index++] * dim];
+      XDrawLine(display, mainwindow, linegc,
+                (int) (point1[0] * xscale + xoffset),
+                (int) (point1[1] * yscale + yoffset),
+                (int) (point2[0] * xscale + xoffset),
+                (int) (point2[1] * yscale + yoffset));
+    }
+  }
+}
+
+void draw_adj(dim, subdomains, ptr, center, xscale, yscale,
+              xoffset, yoffset)
+int dim;
+int subdomains;
+int *ptr;
+REAL *center;
+REAL xscale;
+REAL yscale;
+REAL xoffset;
+REAL yoffset;
+{
+  int i, j;
+  REAL *point1, *point2;
+
+  for (i = 0; i < subdomains; i++) {
+    for (j = i + 1; j < subdomains; j++) {
+      if (ptr[i * subdomains + j]) {
+        point1 = &center[i * dim];
+        point2 = &center[j * dim];
+        XDrawLine(display, mainwindow, linegc,
+                  (int) (point1[0] * xscale + xoffset),
+                  (int) (point1[1] * yscale + yoffset),
+                  (int) (point2[0] * xscale + xoffset),
+                  (int) (point2[1] * yscale + yoffset));
+      }
+    }
+  }
+  for (i = 0; i < subdomains; i++) {
+    point1 = &center[i * dim];
+    if (color) {
+      XSetForeground(display, linegc, colors[i & 63]);
+    }
+    XFillArc(display, mainwindow, linegc,
+             (int) (point1[0] * xscale + xoffset) - 5 - (line_width >> 1),
+             (int) (point1[1] * yscale + yoffset) - 5 - (line_width >> 1),
+             line_width + 10, line_width + 10, 0, 23040);
+  }
+  XSetForeground(display, linegc, showme_foreground);
+}
+
+void draw(inc, image, xmin, ymin, xmax, ymax)
+int inc;
+int image;
+REAL xmin;
+REAL ymin;
+REAL xmax;
+REAL ymax;
+{
+  draw_buttons();
+  XClearWindow(display, mainwindow);
+  if (image == NOTHING) {
+    return;
+  }
+  if (!loaded[inc][image]) {
+    return;
+  }
+  if ((image == PART) && explode) {
+    xmin += (xmin - partcenter[inc][subdomains[inc] << 1]) * explosion;
+    xmax += (xmax - partcenter[inc][subdomains[inc] << 1]) * explosion;
+    ymin += (ymin - partcenter[inc][(subdomains[inc] << 1) + 1]) * explosion;
+    ymax += (ymax - partcenter[inc][(subdomains[inc] << 1) + 1]) * explosion;
+  }
+  xscale = (REAL) (width - line_width - 4) / (xmax - xmin);
+  yscale = (REAL) (height - line_width - 4) / (ymax - ymin);
+  if (xscale > yscale) {
+    xscale = yscale;
+  } else {
+    yscale = xscale;
+  }
+  xoffset = 0.5 * ((REAL) width - xscale * (xmax - xmin)) -
+            xscale * xmin;
+  yoffset = (REAL) height - 0.5 * ((REAL) height - yscale * (ymax - ymin)) +
+            yscale * ymin;
+  yscale = - yscale;
+  switch(image) {
+    case NODE:
+      draw_node(nodes[inc], node_dim[inc], nodeptr[inc],
+                xscale, yscale, xoffset, yoffset);
+      break;
+    case POLY:
+      if (polynodes[inc] > 0) {
+        draw_poly(polynodes[inc], poly_dim[inc], polyedges[inc],
+                  polyholes[inc], polynodeptr[inc], polyedgeptr[inc],
+                  polyholeptr[inc],
+                  xscale, yscale, xoffset, yoffset);
+      } else {
+        draw_poly(nodes[inc], node_dim[inc], polyedges[inc],
+                  polyholes[inc], nodeptr[inc], polyedgeptr[inc],
+                  polyholeptr[inc],
+                  xscale, yscale, xoffset, yoffset);
+      }
+      break;
+    case ELE:
+      draw_ele(inc, elems[inc], ele_corners[inc], eleptr[inc],
+               (int *) NULL, (REAL *) NULL,
+               xscale, yscale, xoffset, yoffset);
+      break;
+    case EDGE:
+      draw_edge(nodes[inc], node_dim[inc], edges[inc],
+                nodeptr[inc], edgeptr[inc], normptr[inc],
+                xscale, yscale, xoffset, yoffset);
+      break;
+    case PART:
+      draw_ele(inc, elems[inc], ele_corners[inc], eleptr[inc],
+               partpart[inc], partshift[inc],
+               xscale, yscale, xoffset, yoffset);
+      break;
+    case ADJ:
+      draw_adj(node_dim[inc], adjsubdomains[inc], adjptr[inc], partcenter[inc],
+               xscale, yscale, xoffset, yoffset);
+      break;
+    case VORO:
+      if (loaded[inc][NODE]) {
+        draw_node(nodes[inc], node_dim[inc], nodeptr[inc],
+                  xscale, yscale, xoffset, yoffset);
+      }
+      draw_edge(vnodes[inc], vnode_dim[inc], vedges[inc],
+                vnodeptr[inc], vedgeptr[inc], vnormptr[inc],
+                xscale, yscale, xoffset, yoffset);
+      break;
+    default:
+      break;
+  }
+}
+
+void addps(instring, outstring, eps)
+char *instring;
+char *outstring;
+int eps;
+{
+  strcpy(outstring, instring);
+  if (eps) {
+    strcat(outstring, ".eps");
+  } else {
+    strcat(outstring, ".ps");
+  }
+}
+
+int print_head(fname, file, llcornerx, llcornery, eps)
+char *fname;
+FILE **file;
+int llcornerx;
+int llcornery;
+int eps;
+{
+  if (!quiet) {
+    printf("Writing %s\n", fname);
+  }
+  *file = fopen(fname, "w");
+  if (*file == (FILE *) NULL) {
+    printf("  Error:  Could not open %s\n", fname);
+    return 1;
+  }
+  if (eps) {
+    fprintf(*file, "%%!PS-Adobe-2.0 EPSF-2.0\n");
+  } else {
+    fprintf(*file, "%%!PS-Adobe-2.0\n");
+  }
+  fprintf(*file, "%%%%BoundingBox: %d %d %d %d\n", llcornerx, llcornery,
+          612 - llcornerx, 792 - llcornery);
+  fprintf(*file, "%%%%Creator: Show Me\n");
+  fprintf(*file, "%%%%EndComments\n\n");
+  fprintf(*file, "1 setlinecap\n");
+  fprintf(*file, "1 setlinejoin\n");
+  fprintf(*file, "%d setlinewidth\n", line_width);
+  fprintf(*file, "%d %d moveto\n", llcornerx, llcornery);
+  fprintf(*file, "%d %d lineto\n", 612 - llcornerx, llcornery);
+  fprintf(*file, "%d %d lineto\n", 612 - llcornerx, 792 - llcornery);
+  fprintf(*file, "%d %d lineto\n", llcornerx, 792 - llcornery);
+  fprintf(*file, "closepath\nclip\nnewpath\n");
+  return 0;
+}
+
+void print_node(nodefile, nodes, dim, ptr, xscale, yscale,
+                xoffset, yoffset)
+FILE *nodefile;
+int nodes;
+int dim;
+REAL *ptr;
+REAL xscale;
+REAL yscale;
+REAL xoffset;
+REAL yoffset;
+{
+  int i;
+  int index;
+
+  index = dim;
+  for (i = 1; i <= nodes; i++) {
+    fprintf(nodefile, "%d %d %d 0 360 arc\nfill\n",
+            (int) (ptr[index] * xscale + xoffset),
+            (int) (ptr[index + 1] * yscale + yoffset),
+            1 + (line_width >> 1));
+    index += dim;
+  }
+}
+
+void print_poly(polyfile, nodes, dim, edges, holes, nodeptr, edgeptr, holeptr,
+                xscale, yscale, xoffset, yoffset)
+FILE *polyfile;
+int nodes;
+int dim;
+int edges;
+int holes;
+REAL *nodeptr;
+int *edgeptr;
+REAL *holeptr;
+REAL xscale;
+REAL yscale;
+REAL xoffset;
+REAL yoffset;
+{
+  int i;
+  int index;
+  REAL *point1, *point2;
+
+  index = dim;
+  for (i = 1; i <= nodes; i++) {
+    fprintf(polyfile, "%d %d %d 0 360 arc\nfill\n",
+            (int) (nodeptr[index] * xscale + xoffset),
+            (int) (nodeptr[index + 1] * yscale + yoffset),
+            1 + (line_width >> 1));
+    index += dim;
+  }
+  index = 2;
+  for (i = 1; i <= edges; i++) {
+    point1 = &nodeptr[edgeptr[index++] * dim];
+    point2 = &nodeptr[edgeptr[index++] * dim];
+    fprintf(polyfile, "%d %d moveto\n",
+            (int) (point1[0] * xscale + xoffset),
+            (int) (point1[1] * yscale + yoffset));
+    fprintf(polyfile, "%d %d lineto\nstroke\n",
+            (int) (point2[0] * xscale + xoffset),
+            (int) (point2[1] * yscale + yoffset));
+  }
+}
+
+void print_ele(elefile, nodes, dim, elems, corners, nodeptr, eleptr,
+               partition, shift,
+               xscale, yscale, xoffset, yoffset, llcornerx, llcornery)
+FILE *elefile;
+int nodes;
+int dim;
+int elems;
+int corners;
+REAL *nodeptr;
+int *eleptr;
+int *partition;
+REAL *shift;
+REAL xscale;
+REAL yscale;
+REAL xoffset;
+REAL yoffset;
+int llcornerx;
+int llcornery;
+{
+  int i, j;
+  int index, colorindex;
+  REAL shiftx, shifty;
+  REAL *nowpoint;
+
+  index = 3;
+  if ((partition != (int *) NULL) && !bw_ps) {
+    fprintf(elefile, "0 0 0 setrgbcolor\n");
+    fprintf(elefile, "%d %d moveto\n", llcornerx, llcornery);
+    fprintf(elefile, "%d %d lineto\n", 612 - llcornerx, llcornery);
+    fprintf(elefile, "%d %d lineto\n", 612 - llcornerx, 792 - llcornery);
+    fprintf(elefile, "%d %d lineto\n", llcornerx, 792 - llcornery);
+    fprintf(elefile, "fill\n");
+  }
+  for (i = 1; i <= elems; i++) {
+    if ((partition != (int *) NULL) && !bw_ps) {
+      colorindex = partition[i] & 63;
+      fprintf(elefile, "%6.3f %6.3f %6.3f setrgbcolor\n",
+              (REAL) rgb[colorindex].red / 65535.0,
+              (REAL) rgb[colorindex].green / 65535.0,
+              (REAL) rgb[colorindex].blue / 65535.0);
+    }
+    nowpoint = &nodeptr[eleptr[index + 2] * dim];
+    if ((partition != (int *) NULL) && (explode || bw_ps)) {
+      shiftx = shift[partition[i] << 1];
+      shifty = shift[(partition[i] << 1) + 1];
+      fprintf(elefile, "%d %d moveto\n",
+              (int) ((nowpoint[0] + shiftx) * xscale + xoffset),
+              (int) ((nowpoint[1] + shifty) * yscale + yoffset));
+      for (j = 0; j < 3; j++) {
+        nowpoint = &nodeptr[eleptr[index++] * dim];
+        fprintf(elefile, "%d %d lineto\n",
+                (int) ((nowpoint[0] + shiftx) * xscale + xoffset),
+                (int) ((nowpoint[1] + shifty) * yscale + yoffset));
+      }
+    } else {
+      fprintf(elefile, "%d %d moveto\n",
+              (int) (nowpoint[0] * xscale + xoffset),
+              (int) (nowpoint[1] * yscale + yoffset));
+      for (j = 0; j < 3; j++) {
+        nowpoint = &nodeptr[eleptr[index++] * dim];
+        fprintf(elefile, "%d %d lineto\n",
+                (int) (nowpoint[0] * xscale + xoffset),
+                (int) (nowpoint[1] * yscale + yoffset));
+      }
+    }
+    if (fillelem && !bw_ps) {
+      fprintf(elefile, "gsave\nfill\ngrestore\n1 1 0 setrgbcolor\n");
+    }
+    fprintf(elefile, "stroke\n");
+  }
+}
+
+void print_edge(edgefile, nodes, dim, edges, nodeptr, edgeptr, normptr,
+                xscale, yscale, xoffset, yoffset, llcornerx, llcornery)
+FILE *edgefile;
+int nodes;
+int dim;
+int edges;
+REAL *nodeptr;
+int *edgeptr;
+REAL *normptr;
+REAL xscale;
+REAL yscale;
+REAL xoffset;
+REAL yoffset;
+int llcornerx;
+int llcornery;
+{
+  int i;
+  int index;
+  REAL *point1, *point2;
+  REAL normx, normy;
+  REAL normmult, normmultx, normmulty;
+  REAL windowxmin, windowymin, windowxmax, windowymax;
+
+  index = 2;
+  for (i = 1; i <= edges; i++) {
+    point1 = &nodeptr[edgeptr[index++] * dim];
+    if (edgeptr[index] == -1) {
+      normx = normptr[index - 1];
+      normy = normptr[index++];
+      normmultx = 0.0;
+      if (normx > 0) {
+        windowxmax = ((REAL) (612 - llcornerx) - xoffset) / xscale;
+        normmultx = (windowxmax - point1[0]) / normx;
+      } else if (normx < 0) {
+        windowxmin = ((REAL) llcornerx - xoffset) / xscale;
+        normmultx = (windowxmin - point1[0]) / normx;
+      }
+      normmulty = 0.0;
+      if (normy > 0) {
+        windowymax = ((REAL) (792 - llcornery) - yoffset) / yscale;
+        normmulty = (windowymax - point1[1]) / normy;
+      } else if (normy < 0) {
+        windowymin = ((REAL) llcornery - yoffset) / yscale;
+        normmulty = (windowymin - point1[1]) / normy;
+      }
+      if (normmultx == 0.0) {
+        normmult = normmulty;
+      } else if (normmulty == 0.0) {
+        normmult = normmultx;
+      } else if (normmultx < normmulty) {
+        normmult = normmultx;
+      } else {
+        normmult = normmulty;
+      }
+      if (normmult > 0.0) {
+        fprintf(edgefile, "%d %d moveto\n",
+                (int) (point1[0] * xscale + xoffset),
+                (int) (point1[1] * yscale + yoffset));
+        fprintf(edgefile, "%d %d lineto\nstroke\n",
+                (int) ((point1[0] + normmult * normx) * xscale + xoffset),
+                (int) ((point1[1] + normmult * normy) * yscale + yoffset));
+      }
+    } else {
+      point2 = &nodeptr[edgeptr[index++] * dim];
+      fprintf(edgefile, "%d %d moveto\n",
+              (int) (point1[0] * xscale + xoffset),
+              (int) (point1[1] * yscale + yoffset));
+      fprintf(edgefile, "%d %d lineto\nstroke\n",
+              (int) (point2[0] * xscale + xoffset),
+              (int) (point2[1] * yscale + yoffset));
+    }
+  }
+}
+
+void print_adj(adjfile, dim, subdomains, ptr, center, xscale, yscale,
+               xoffset, yoffset, llcornerx, llcornery)
+FILE *adjfile;
+int dim;
+int subdomains;
+int *ptr;
+REAL *center;
+REAL xscale;
+REAL yscale;
+REAL xoffset;
+REAL yoffset;
+int llcornerx;
+int llcornery;
+{
+  int i, j;
+  REAL *point1, *point2;
+  int colorindex;
+
+  if (!bw_ps) {
+    fprintf(adjfile, "0 0 0 setrgbcolor\n");
+    fprintf(adjfile, "%d %d moveto\n", llcornerx, llcornery);
+    fprintf(adjfile, "%d %d lineto\n", 612 - llcornerx, llcornery);
+    fprintf(adjfile, "%d %d lineto\n", 612 - llcornerx, 792 - llcornery);
+    fprintf(adjfile, "%d %d lineto\n", llcornerx, 792 - llcornery);
+    fprintf(adjfile, "fill\n");
+    fprintf(adjfile, "1 1 0 setrgbcolor\n");
+  }
+  for (i = 0; i < subdomains; i++) {
+    for (j = i + 1; j < subdomains; j++) {
+      if (ptr[i * subdomains + j]) {
+        point1 = &center[i * dim];
+        point2 = &center[j * dim];
+        fprintf(adjfile, "%d %d moveto\n",
+                (int) (point1[0] * xscale + xoffset),
+                (int) (point1[1] * yscale + yoffset));
+        fprintf(adjfile, "%d %d lineto\nstroke\n",
+                (int) (point2[0] * xscale + xoffset),
+                (int) (point2[1] * yscale + yoffset));
+      }
+    }
+  }
+  for (i = 0; i < subdomains; i++) {
+    point1 = &center[i * dim];
+    if (!bw_ps) {
+      colorindex = i & 63;
+      fprintf(adjfile, "%6.3f %6.3f %6.3f setrgbcolor\n",
+              (REAL) rgb[colorindex].red / 65535.0,
+              (REAL) rgb[colorindex].green / 65535.0,
+              (REAL) rgb[colorindex].blue / 65535.0);
+      fprintf(adjfile, "%d %d %d 0 360 arc\nfill\n",
+              (int) (point1[0] * xscale + xoffset),
+              (int) (point1[1] * yscale + yoffset),
+              5 + (line_width >> 1));
+    } else {
+      fprintf(adjfile, "%d %d %d 0 360 arc\nfill\n",
+              (int) (point1[0] * xscale + xoffset),
+              (int) (point1[1] * yscale + yoffset),
+              3 + (line_width >> 1));
+    }
+  }
+}
+
+void print(inc, image, xmin, ymin, xmax, ymax, eps)
+int inc;
+int image;
+REAL xmin;
+REAL ymin;
+REAL xmax;
+REAL ymax;
+int eps;
+{
+  REAL xxscale, yyscale, xxoffset, yyoffset;
+  char psfilename[FILENAMESIZE];
+  int llcornerx, llcornery;
+  FILE *psfile;
+
+  if (image == NOTHING) {
+    return;
+  }
+  if (!loaded[inc][image]) {
+    return;
+  }
+  if ((image == PART) && (explode || bw_ps)) {
+    xmin += (xmin - partcenter[inc][subdomains[inc] << 1]) * explosion;
+    xmax += (xmax - partcenter[inc][subdomains[inc] << 1]) * explosion;
+    ymin += (ymin - partcenter[inc][(subdomains[inc] << 1) + 1]) * explosion;
+    ymax += (ymax - partcenter[inc][(subdomains[inc] << 1) + 1]) * explosion;
+  }
+  xxscale = (460.0 - (REAL) line_width) / (xmax - xmin);
+  yyscale = (640.0 - (REAL) line_width) / (ymax - ymin);
+  if (xxscale > yyscale) {
+    xxscale = yyscale;
+    llcornerx = (604 - (int) (yyscale * (xmax - xmin)) - line_width) >> 1;
+    llcornery = 72;
+  } else {
+    yyscale = xxscale;
+    llcornerx = 72;
+    llcornery = (784 - (int) (xxscale * (ymax - ymin)) - line_width) >> 1;
+  }
+  xxoffset = 0.5 * (612.0 - xxscale * (xmax - xmin)) - xxscale * xmin +
+             (line_width >> 1);
+  yyoffset = 0.5 * (792.0 - yyscale * (ymax - ymin)) - yyscale * ymin +
+             (line_width >> 1);
+  switch(image) {
+    case NODE:
+      addps(nodefilename[inc], psfilename, eps);
+      break;
+    case POLY:
+      addps(polyfilename[inc], psfilename, eps);
+      break;
+    case ELE:
+      addps(elefilename[inc], psfilename, eps);
+      break;
+    case EDGE:
+      addps(edgefilename[inc], psfilename, eps);
+      break;
+    case PART:
+      addps(partfilename[inc], psfilename, eps);
+      break;
+    case ADJ:
+      addps(adjfilename[inc], psfilename, eps);
+      break;
+    case VORO:
+      addps(vedgefilename[inc], psfilename, eps);
+      break;
+    default:
+      break;
+  }
+  if (print_head(psfilename, &psfile, llcornerx, llcornery, eps)) {
+    return;
+  }
+  switch(image) {
+    case NODE:
+      print_node(psfile, nodes[inc], node_dim[inc], nodeptr[inc],
+                 xxscale, yyscale, xxoffset, yyoffset);
+      break;
+    case POLY:
+      if (polynodes[inc] > 0) {
+        print_poly(psfile, polynodes[inc], poly_dim[inc], polyedges[inc],
+                   polyholes[inc], polynodeptr[inc], polyedgeptr[inc],
+                   polyholeptr[inc], xxscale, yyscale, xxoffset, yyoffset);
+      } else {
+        print_poly(psfile, nodes[inc], node_dim[inc], polyedges[inc],
+                   polyholes[inc], nodeptr[inc], polyedgeptr[inc],
+                   polyholeptr[inc], xxscale, yyscale, xxoffset, yyoffset);
+      }
+      break;
+    case ELE:
+      print_ele(psfile, nodes[inc], node_dim[inc], elems[inc],
+                ele_corners[inc], nodeptr[inc], eleptr[inc],
+                (int *) NULL, (REAL *) NULL,
+                xxscale, yyscale, xxoffset, yyoffset, llcornerx, llcornery);
+      break;
+    case EDGE:
+      print_edge(psfile, nodes[inc], node_dim[inc], edges[inc],
+                 nodeptr[inc], edgeptr[inc], normptr[inc],
+                 xxscale, yyscale, xxoffset, yyoffset, llcornerx, llcornery);
+      break;
+    case PART:
+      print_ele(psfile, nodes[inc], node_dim[inc], elems[inc],
+                ele_corners[inc], nodeptr[inc], eleptr[inc],
+                partpart[inc], partshift[inc],
+                xxscale, yyscale, xxoffset, yyoffset, llcornerx, llcornery);
+      break;
+    case ADJ:
+      print_adj(psfile, node_dim[inc], adjsubdomains[inc], adjptr[inc],
+                partcenter[inc],
+                xxscale, yyscale, xxoffset, yyoffset, llcornerx, llcornery);
+      break;
+    case VORO:
+      print_edge(psfile, vnodes[inc], vnode_dim[inc], vedges[inc],
+                 vnodeptr[inc], vedgeptr[inc], vnormptr[inc],
+                 xxscale, yyscale, xxoffset, yyoffset, llcornerx, llcornery);
+      break;
+    default:
+      break;
+  }
+  if (!eps) {
+    fprintf(psfile, "showpage\n");
+  }
+  fclose(psfile);
+}
+
+int main(argc, argv)
+int argc;
+char **argv;
+{
+  REAL xmin, ymin, xmax, ymax;
+  REAL xptr, yptr, xspan, yspan;
+  int past_image;
+  int new_image;
+  int new_inc;
+
+  parsecommandline(argc, argv);
+  showme_init();
+  choose_image(start_inc, start_image);
+  showme_window(argc, argv);
+
+  if (current_image != NOTHING) {
+    xmin = xlo[current_inc][current_image];
+    ymin = ylo[current_inc][current_image];
+    xmax = xhi[current_inc][current_image];
+    ymax = yhi[current_inc][current_image];
+    zoom = 0;
+  }
+
+  XMaskEvent(display, ExposureMask, &event);
+  while (1) {
+    switch (event.type) {
+      case ButtonRelease:
+        if (event.xany.window == quitwin) {
+          XDestroyWindow(display, mainwindow);
+          XCloseDisplay(display);
+          return 0;
+        } else if (event.xany.window == leftwin) {
+          xspan = 0.25 * (xmax - xmin);
+          xmin += xspan;
+          xmax += xspan;
+          draw(current_inc, current_image, xmin, ymin, xmax, ymax);
+        } else if (event.xany.window == rightwin) {
+          xspan = 0.25 * (xmax - xmin);
+          xmin -= xspan;
+          xmax -= xspan;
+          draw(current_inc, current_image, xmin, ymin, xmax, ymax);
+        } else if (event.xany.window == upwin) {
+          yspan = 0.25 * (ymax - ymin);
+          ymin -= yspan;
+          ymax -= yspan;
+          draw(current_inc, current_image, xmin, ymin, xmax, ymax);
+        } else if (event.xany.window == downwin) {
+          yspan = 0.25 * (ymax - ymin);
+          ymin += yspan;
+          ymax += yspan;
+          draw(current_inc, current_image, xmin, ymin, xmax, ymax);
+        } else if (event.xany.window == resetwin) {
+          xmin = xlo[current_inc][current_image];
+          ymin = ylo[current_inc][current_image];
+          xmax = xhi[current_inc][current_image];
+          ymax = yhi[current_inc][current_image];
+          zoom = 0;
+          draw(current_inc, current_image, xmin, ymin, xmax, ymax);
+        } else if (event.xany.window == widthpluswin) {
+          if (line_width < 100) {
+            line_width++;
+            XSetLineAttributes(display, linegc, line_width, LineSolid,
+                               CapRound, JoinRound);
+            XSetLineAttributes(display, trianglegc, line_width, LineSolid,
+                               CapRound, JoinRound);
+            draw(current_inc, current_image, xmin, ymin, xmax, ymax);
+          }
+        } else if (event.xany.window == widthminuswin) {
+          if (line_width > 1) {
+            line_width--;
+            XSetLineAttributes(display, linegc, line_width, LineSolid,
+                               CapRound, JoinRound);
+            XSetLineAttributes(display, trianglegc, line_width, LineSolid,
+                               CapRound, JoinRound);
+            draw(current_inc, current_image, xmin, ymin, xmax, ymax);
+          }
+        } else if (event.xany.window == expwin) {
+          if ((current_image == PART) && loaded[current_inc][PART]) {
+            explode = !explode;
+            draw(current_inc, current_image, xmin, ymin, xmax, ymax);
+          }
+        } else if (event.xany.window == exppluswin) {
+          if ((current_image == PART) && loaded[PART] && explode) {
+            explosion += 0.125;
+            findpartshift(subdomains[current_inc], explosion,
+                          partcenter[current_inc], partshift[current_inc]);
+            draw(current_inc, current_image, xmin, ymin, xmax, ymax);
+          }
+        } else if (event.xany.window == expminuswin) {
+          if ((current_image == PART) && loaded[PART] && explode &&
+              (explosion >= 0.125)) {
+            explosion -= 0.125;
+            findpartshift(subdomains[current_inc], explosion,
+                          partcenter[current_inc], partshift[current_inc]);
+            draw(current_inc, current_image, xmin, ymin, xmax, ymax);
+          }
+        } else if (event.xany.window == fillwin) {
+          if ((current_image == PART) && loaded[PART]) {
+            fillelem = !fillelem;
+            draw(current_inc, current_image, xmin, ymin, xmax, ymax);
+          }
+        } else if (event.xany.window == pswin) {
+          fill_button(pswin);
+          XFlush(display);
+          print(current_inc, current_image, xmin, ymin, xmax, ymax, 0);
+          XClearWindow(display, pswin);
+          XDrawString(display, pswin, fontgc, 2, 13, "PS", 2);
+        } else if (event.xany.window == epswin) {
+          fill_button(epswin);
+          XFlush(display);
+          print(current_inc, current_image, xmin, ymin, xmax, ymax, 1);
+          XClearWindow(display, epswin);
+          XDrawString(display, epswin, fontgc, 2, 13, "EPS", 3);
+        } else if (event.xany.window == versionpluswin) {
+          move_inc(1);
+          loweriteration++;
+          set_filenames(filename, loweriteration);
+          if (current_inc == 1) {
+            current_inc = 0;
+          } else {
+            current_image = NOTHING;
+            XClearWindow(display, mainwindow);
+          }
+          draw_buttons();
+        } else if (event.xany.window == versionminuswin) {
+          if (loweriteration > 0) {
+            move_inc(0);
+            loweriteration--;
+            set_filenames(filename, loweriteration);
+            if (current_inc == 0) {
+              current_inc = 1;
+            } else {
+              current_image = NOTHING;
+              XClearWindow(display, mainwindow);
+            }
+            draw_buttons();
+          }
+        } else if ((event.xany.window == nodewin[0]) ||
+                   (event.xany.window == polywin[0]) ||
+                   (event.xany.window == elewin[0]) ||
+                   (event.xany.window == edgewin[0]) ||
+                   (event.xany.window == partwin[0]) ||
+                   (event.xany.window == adjwin[0]) ||
+                   (event.xany.window == voronoiwin[0]) ||
+                   (event.xany.window == nodewin[1]) ||
+                   (event.xany.window == polywin[1]) ||
+                   (event.xany.window == elewin[1]) ||
+                   (event.xany.window == edgewin[1]) ||
+                   (event.xany.window == partwin[1]) ||
+                   (event.xany.window == adjwin[1]) ||
+                   (event.xany.window == voronoiwin[1])) {
+          if (event.xany.window == nodewin[0]) {
+            new_inc = 0;
+            new_image = NODE;
+          }
+          if (event.xany.window == polywin[0]) {
+            new_inc = 0;
+            new_image = POLY;
+          }
+          if (event.xany.window == elewin[0]) {
+            new_inc = 0;
+            new_image = ELE;
+          }
+          if (event.xany.window == edgewin[0]) {
+            new_inc = 0;
+            new_image = EDGE;
+          }
+          if (event.xany.window == partwin[0]) {
+            new_inc = 0;
+            new_image = PART;
+          }
+          if (event.xany.window == adjwin[0]) {
+            new_inc = 0;
+            new_image = ADJ;
+          }
+          if (event.xany.window == voronoiwin[0]) {
+            new_inc = 0;
+            new_image = VORO;
+          }
+          if (event.xany.window == nodewin[1]) {
+            new_inc = 1;
+            new_image = NODE;
+          }
+          if (event.xany.window == polywin[1]) {
+            new_inc = 1;
+            new_image = POLY;
+          }
+          if (event.xany.window == elewin[1]) {
+            new_inc = 1;
+            new_image = ELE;
+          }
+          if (event.xany.window == edgewin[1]) {
+            new_inc = 1;
+            new_image = EDGE;
+          }
+          if (event.xany.window == partwin[1]) {
+            new_inc = 1;
+            new_image = PART;
+          }
+          if (event.xany.window == adjwin[1]) {
+            new_inc = 1;
+            new_image = ADJ;
+          }
+          if (event.xany.window == voronoiwin[1]) {
+            new_inc = 1;
+            new_image = VORO;
+          }
+          past_image = current_image;
+          if ((current_inc == new_inc) && (current_image == new_image)) {
+            free_inc(new_inc);
+            unload_inc(new_inc);
+          }
+          choose_image(new_inc, new_image);
+          if ((past_image == NOTHING) && (current_image != NOTHING)) {
+            xmin = xlo[current_inc][current_image];
+            ymin = ylo[current_inc][current_image];
+            xmax = xhi[current_inc][current_image];
+            ymax = yhi[current_inc][current_image];
+            zoom = 0;
+          }
+          draw(current_inc, current_image, xmin, ymin, xmax, ymax);
+        } else {
+          xptr = ((REAL) event.xbutton.x - xoffset) / xscale;
+          yptr = ((REAL) event.xbutton.y - yoffset) / yscale;
+          if ((current_image == PART) && loaded[PART] && explode) {
+            xptr = (xptr + partcenter[current_inc]
+                                     [subdomains[current_inc] << 1]
+                    * explosion) / (1.0 + explosion);
+            yptr = (yptr + partcenter[current_inc]
+                                     [(subdomains[current_inc] << 1) + 1]
+                    * explosion) / (1.0 + explosion);
+          }
+          if ((event.xbutton.button == Button1)
+              || (event.xbutton.button == Button3)) {
+            if (event.xbutton.button == Button1) {
+              xspan = 0.25 * (xmax - xmin);
+              yspan = 0.25 * (ymax - ymin);
+              zoom++;
+            } else {
+              xspan = xmax - xmin;
+              yspan = ymax - ymin;
+              zoom--;
+            }
+            xmin = xptr - xspan;
+            ymin = yptr - yspan;
+            xmax = xptr + xspan;
+            ymax = yptr + yspan;
+            draw(current_inc, current_image, xmin, ymin, xmax, ymax);
+          } else if (event.xbutton.button == Button2) {
+            printf("x = %.4g, y = %.4g\n", xptr, yptr);
+          }
+        }
+        break;
+      case DestroyNotify:
+        XDestroyWindow(display, mainwindow);
+        XCloseDisplay(display);
+        return 0;
+      case ConfigureNotify:
+        if ((width != event.xconfigure.width) ||
+            (height != event.xconfigure.height - PANELHEIGHT)) {
+          width = event.xconfigure.width;
+          height = event.xconfigure.height - PANELHEIGHT;
+          draw(current_inc, current_image, xmin, ymin, xmax, ymax);
+          while (XCheckMaskEvent(display, ExposureMask, &event));
+        }
+        break;
+      case Expose:
+        draw(current_inc, current_image, xmin, ymin, xmax, ymax);
+        while (XCheckMaskEvent(display, ExposureMask, &event));
+        break;
+      default:
+        break;
+    }
+    XNextEvent(display, &event);
+  }
+}

diff --git a/Triangle/triangle.c b/Triangle/triangle.c
new file mode 100644 (file)
index 0000000..67bd00d
--- /dev/null
+++ b/Triangle/triangle.c
@@ -0,0 +1,13232 @@
+/*****************************************************************************/
+/*                                                                           */
+/*      888888888        ,o,                          / 888                  */
+/*         888    88o88o  "    o8888o  88o8888o o88888o 888  o88888o         */
+/*         888    888    888       88b 888  888 888 888 888 d888  88b        */
+/*         888    888    888  o88^o888 888  888 "88888" 888 8888oo888        */
+/*         888    888    888 C888  888 888  888  /      888 q888             */
+/*         888    888    888  "88o^888 888  888 Cb      888  "88oooo"        */
+/*                                              "8oo8D                       */
+/*                                                                           */
+/*  A Two-Dimensional Quality Mesh Generator and Delaunay Triangulator.      */
+/*  (triangle.c)                                                             */
+/*                                                                           */
+/*  Version 1.3                                                              */
+/*  July 19, 1996                                                            */
+/*                                                                           */
+/*  Copyright 1996                                                           */
+/*  Jonathan Richard Shewchuk                                                */
+/*  School of Computer Science                                               */
+/*  Carnegie Mellon University                                               */
+/*  5000 Forbes Avenue                                                       */
+/*  Pittsburgh, Pennsylvania  15213-3891                                     */
+/*  jrs@cs.cmu.edu                                                           */
+/*                                                                           */
+/*  This program may be freely redistributed under the condition that the    */
+/*    copyright notices (including this entire header and the copyright      */
+/*    notice printed when the `-h' switch is selected) are not removed, and  */
+/*    no compensation is received.  Private, research, and institutional     */
+/*    use is free.  You may distribute modified versions of this code UNDER  */
+/*    THE CONDITION THAT THIS CODE AND ANY MODIFICATIONS MADE TO IT IN THE   */
+/*    SAME FILE REMAIN UNDER COPYRIGHT OF THE ORIGINAL AUTHOR, BOTH SOURCE   */
+/*    AND OBJECT CODE ARE MADE FREELY AVAILABLE WITHOUT CHARGE, AND CLEAR    */
+/*    NOTICE IS GIVEN OF THE MODIFICATIONS.  Distribution of this code as    */
+/*    part of a commercial system is permissible ONLY BY DIRECT ARRANGEMENT  */
+/*    WITH THE AUTHOR.  (If you are not directly supplying this code to a    */
+/*    customer, and you are instead telling them how they can obtain it for  */
+/*    free, then you are not required to make any arrangement with me.)      */
+/*                                                                           */
+/*  Hypertext instructions for Triangle are available on the Web at          */
+/*                                                                           */
+/*      http://www.cs.cmu.edu/~quake/triangle.html                           */
+/*                                                                           */
+/*  Some of the references listed below are marked [*].  These are available */
+/*    for downloading from the Web page                                      */
+/*                                                                           */
+/*      http://www.cs.cmu.edu/~quake/triangle.research.html                  */
+/*                                                                           */
+/*  A paper discussing some aspects of Triangle is available.  See Jonathan  */
+/*    Richard Shewchuk, "Triangle:  Engineering a 2D Quality Mesh Generator  */
+/*    and Delaunay Triangulator," First Workshop on Applied Computational    */
+/*    Geometry, ACM, May 1996.  [*]                                          */
+/*                                                                           */
+/*  Triangle was created as part of the Archimedes project in the School of  */
+/*    Computer Science at Carnegie Mellon University.  Archimedes is a       */
+/*    system for compiling parallel finite element solvers.  For further     */
+/*    information, see Anja Feldmann, Omar Ghattas, John R. Gilbert, Gary L. */
+/*    Miller, David R. O'Hallaron, Eric J. Schwabe, Jonathan R. Shewchuk,    */
+/*    and Shang-Hua Teng, "Automated Parallel Solution of Unstructured PDE   */
+/*    Problems."  To appear in Communications of the ACM, we hope.           */
+/*                                                                           */
+/*  The quality mesh generation algorithm is due to Jim Ruppert, "A          */
+/*    Delaunay Refinement Algorithm for Quality 2-Dimensional Mesh           */
+/*    Generation," Journal of Algorithms 18(3):548-585, May 1995.  [*]       */
+/*                                                                           */
+/*  My implementation of the divide-and-conquer and incremental Delaunay     */
+/*    triangulation algorithms follows closely the presentation of Guibas    */
+/*    and Stolfi, even though I use a triangle-based data structure instead  */
+/*    of their quad-edge data structure.  (In fact, I originally implemented */
+/*    Triangle using the quad-edge data structure, but switching to a        */
+/*    triangle-based data structure sped Triangle by a factor of two.)  The  */
+/*    mesh manipulation primitives and the two aforementioned Delaunay       */
+/*    triangulation algorithms are described by Leonidas J. Guibas and Jorge */
+/*    Stolfi, "Primitives for the Manipulation of General Subdivisions and   */
+/*    the Computation of Voronoi Diagrams," ACM Transactions on Graphics     */
+/*    4(2):74-123, April 1985.                                               */
+/*                                                                           */
+/*  Their O(n log n) divide-and-conquer algorithm is adapted from Der-Tsai   */
+/*    Lee and Bruce J. Schachter, "Two Algorithms for Constructing the       */
+/*    Delaunay Triangulation," International Journal of Computer and         */
+/*    Information Science 9(3):219-242, 1980.  The idea to improve the       */
+/*    divide-and-conquer algorithm by alternating between vertical and       */
+/*    horizontal cuts was introduced by Rex A. Dwyer, "A Faster Divide-and-  */
+/*    Conquer Algorithm for Constructing Delaunay Triangulations,"           */
+/*    Algorithmica 2(2):137-151, 1987.                                       */
+/*                                                                           */
+/*  The incremental insertion algorithm was first proposed by C. L. Lawson,  */
+/*    "Software for C1 Surface Interpolation," in Mathematical Software III, */
+/*    John R. Rice, editor, Academic Press, New York, pp. 161-194, 1977.     */
+/*    For point location, I use the algorithm of Ernst P. Mucke, Isaac       */
+/*    Saias, and Binhai Zhu, "Fast Randomized Point Location Without         */
+/*    Preprocessing in Two- and Three-dimensional Delaunay Triangulations,"  */
+/*    Proceedings of the Twelfth Annual Symposium on Computational Geometry, */
+/*    ACM, May 1996.  [*]  If I were to randomize the order of point         */
+/*    insertion (I currently don't bother), their result combined with the   */
+/*    result of Leonidas J. Guibas, Donald E. Knuth, and Micha Sharir,       */
+/*    "Randomized Incremental Construction of Delaunay and Voronoi           */
+/*    Diagrams," Algorithmica 7(4):381-413, 1992, would yield an expected    */
+/*    O(n^{4/3}) bound on running time.                                      */
+/*                                                                           */
+/*  The O(n log n) sweepline Delaunay triangulation algorithm is taken from  */
+/*    Steven Fortune, "A Sweepline Algorithm for Voronoi Diagrams",          */
+/*    Algorithmica 2(2):153-174, 1987.  A random sample of edges on the      */
+/*    boundary of the triangulation are maintained in a splay tree for the   */
+/*    purpose of point location.  Splay trees are described by Daniel        */
+/*    Dominic Sleator and Robert Endre Tarjan, "Self-Adjusting Binary Search */
+/*    Trees," Journal of the ACM 32(3):652-686, July 1985.                   */
+/*                                                                           */
+/*  The algorithms for exact computation of the signs of determinants are    */
+/*    described in Jonathan Richard Shewchuk, "Adaptive Precision Floating-  */
+/*    Point Arithmetic and Fast Robust Geometric Predicates," Technical      */
+/*    Report CMU-CS-96-140, School of Computer Science, Carnegie Mellon      */
+/*    University, Pittsburgh, Pennsylvania, May 1996.  [*]  (Submitted to    */
+/*    Discrete & Computational Geometry.)  An abbreviated version appears as */
+/*    Jonathan Richard Shewchuk, "Robust Adaptive Floating-Point Geometric   */
+/*    Predicates," Proceedings of the Twelfth Annual Symposium on Computa-   */
+/*    tional Geometry, ACM, May 1996.  [*]  Many of the ideas for my exact   */
+/*    arithmetic routines originate with Douglas M. Priest, "Algorithms for  */
+/*    Arbitrary Precision Floating Point Arithmetic," Tenth Symposium on     */
+/*    Computer Arithmetic, 132-143, IEEE Computer Society Press, 1991.  [*]  */
+/*    Many of the ideas for the correct evaluation of the signs of           */
+/*    determinants are taken from Steven Fortune and Christopher J. Van Wyk, */
+/*    "Efficient Exact Arithmetic for Computational Geometry," Proceedings   */
+/*    of the Ninth Annual Symposium on Computational Geometry, ACM,          */
+/*    pp. 163-172, May 1993, and from Steven Fortune, "Numerical Stability   */
+/*    of Algorithms for 2D Delaunay Triangulations," International Journal   */
+/*    of Computational Geometry & Applications 5(1-2):193-213, March-June    */
+/*    1995.                                                                  */
+/*                                                                           */
+/*  For definitions of and results involving Delaunay triangulations,        */
+/*    constrained and conforming versions thereof, and other aspects of      */
+/*    triangular mesh generation, see the excellent survey by Marshall Bern  */
+/*    and David Eppstein, "Mesh Generation and Optimal Triangulation," in    */
+/*    Computing and Euclidean Geometry, Ding-Zhu Du and Frank Hwang,         */
+/*    editors, World Scientific, Singapore, pp. 23-90, 1992.                 */
+/*                                                                           */
+/*  The time for incrementally adding PSLG (planar straight line graph)      */
+/*    segments to create a constrained Delaunay triangulation is probably    */
+/*    O(n^2) per segment in the worst case and O(n) per edge in the common   */
+/*    case, where n is the number of triangles that intersect the segment    */
+/*    before it is inserted.  This doesn't count point location, which can   */
+/*    be much more expensive.  (This note does not apply to conforming       */
+/*    Delaunay triangulations, for which a different method is used to       */
+/*    insert segments.)                                                      */
+/*                                                                           */
+/*  The time for adding segments to a conforming Delaunay triangulation is   */
+/*    not clear, but does not depend upon n alone.  In some cases, very      */
+/*    small features (like a point lying next to a segment) can cause a      */
+/*    single segment to be split an arbitrary number of times.  Of course,   */
+/*    floating-point precision is a practical barrier to how much this can   */
+/*    happen.                                                                */
+/*                                                                           */
+/*  The time for deleting a point from a Delaunay triangulation is O(n^2) in */
+/*    the worst case and O(n) in the common case, where n is the degree of   */
+/*    the point being deleted.  I could improve this to expected O(n) time   */
+/*    by "inserting" the neighboring vertices in random order, but n is      */
+/*    usually quite small, so it's not worth the bother.  (The O(n) time     */
+/*    for random insertion follows from L. Paul Chew, "Building Voronoi      */
+/*    Diagrams for Convex Polygons in Linear Expected Time," Technical       */
+/*    Report PCS-TR90-147, Department of Mathematics and Computer Science,   */
+/*    Dartmouth College, 1990.                                               */
+/*                                                                           */
+/*  Ruppert's Delaunay refinement algorithm typically generates triangles    */
+/*    at a linear rate (constant time per triangle) after the initial        */
+/*    triangulation is formed.  There may be pathological cases where more   */
+/*    time is required, but these never arise in practice.                   */
+/*                                                                           */
+/*  The segment intersection formulae are straightforward.  If you want to   */
+/*    see them derived, see Franklin Antonio.  "Faster Line Segment          */
+/*    Intersection."  In Graphics Gems III (David Kirk, editor), pp. 199-    */
+/*    202.  Academic Press, Boston, 1992.                                    */
+/*                                                                           */
+/*  If you make any improvements to this code, please please please let me   */
+/*    know, so that I may obtain the improvements.  Even if you don't change */
+/*    the code, I'd still love to hear what it's being used for.             */
+/*                                                                           */
+/*  Disclaimer:  Neither I nor Carnegie Mellon warrant this code in any way  */
+/*    whatsoever.  This code is provided "as-is".  Use at your own risk.     */
+/*                                                                           */
+/*****************************************************************************/
+
+/* For single precision (which will save some memory and reduce paging),     */
+/*   define the symbol SINGLE by using the -DSINGLE compiler switch or by    */
+/*   writing "#define SINGLE" below.                                         */
+/*                                                                           */
+/* For double precision (which will allow you to refine meshes to a smaller  */
+/*   edge length), leave SINGLE undefined.                                   */
+/*                                                                           */
+/* Double precision uses more memory, but improves the resolution of the     */
+/*   meshes you can generate with Triangle.  It also reduces the likelihood  */
+/*   of a floating exception due to overflow.  Finally, it is much faster    */
+/*   than single precision on 64-bit architectures like the DEC Alpha.  I    */
+/*   recommend double precision unless you want to generate a mesh for which */
+/*   you do not have enough memory.                                          */
+
+/* #define SINGLE */
+
+#ifdef SINGLE
+#define REAL float
+#else /* not SINGLE */
+#define REAL double
+#endif /* not SINGLE */
+
+/* If yours is not a Unix system, define the NO_TIMER compiler switch to     */
+/*   remove the Unix-specific timing code.                                   */
+
+/* #define NO_TIMER */
+
+/* To insert lots of self-checks for internal errors, define the SELF_CHECK  */
+/*   symbol.  This will slow down the program significantly.  It is best to  */
+/*   define the symbol using the -DSELF_CHECK compiler switch, but you could */
+/*   write "#define SELF_CHECK" below.  If you are modifying this code, I    */
+/*   recommend you turn self-checks on.                                      */
+
+/* #define SELF_CHECK */
+
+/* To compile Triangle as a callable object library (triangle.o), define the */
+/*   TRILIBRARY symbol.  Read the file triangle.h for details on how to call */
+/*   the procedure triangulate() that results.                               */
+
+/* #define TRILIBRARY */
+
+/* It is possible to generate a smaller version of Triangle using one or     */
+/*   both of the following symbols.  Define the REDUCED symbol to eliminate  */
+/*   all features that are primarily of research interest; specifically, the */
+/*   -i, -F, -s, and -C switches.  Define the CDT_ONLY symbol to eliminate   */
+/*   all meshing algorithms above and beyond constrained Delaunay            */
+/*   triangulation; specifically, the -r, -q, -a, -S, and -s switches.       */
+/*   These reductions are most likely to be useful when generating an object */
+/*   library (triangle.o) by defining the TRILIBRARY symbol.                 */
+
+/* #define REDUCED */
+/* #define CDT_ONLY */
+
+/* On some machines, the exact arithmetic routines might be defeated by the  */
+/*   use of internal extended precision floating-point registers.  Sometimes */
+/*   this problem can be fixed by defining certain values to be volatile,    */
+/*   thus forcing them to be stored to memory and rounded off.  This isn't   */
+/*   a great solution, though, as it slows Triangle down.                    */
+/*                                                                           */
+/* To try this out, write "#define INEXACT volatile" below.  Normally,       */
+/*   however, INEXACT should be defined to be nothing.  ("#define INEXACT".) */
+
+#define INEXACT /* Nothing */
+/* #define INEXACT volatile */
+
+/* Maximum number of characters in a file name (including the null).         */
+
+#define FILENAMESIZE 512
+
+/* Maximum number of characters in a line read from a file (including the    */
+/*   null).                                                                  */
+
+#define INPUTLINESIZE 512
+
+/* For efficiency, a variety of data structures are allocated in bulk.  The  */
+/*   following constants determine how many of each structure is allocated   */
+/*   at once.                                                                */
+
+#define TRIPERBLOCK 4092           /* Number of triangles allocated at once. */
+#define SHELLEPERBLOCK 508       /* Number of shell edges allocated at once. */
+#define POINTPERBLOCK 4092            /* Number of points allocated at once. */
+#define VIRUSPERBLOCK 1020   /* Number of virus triangles allocated at once. */
+/* Number of encroached segments allocated at once. */
+#define BADSEGMENTPERBLOCK 252
+/* Number of skinny triangles allocated at once. */
+#define BADTRIPERBLOCK 4092
+/* Number of splay tree nodes allocated at once. */
+#define SPLAYNODEPERBLOCK 508
+
+/* The point marker DEADPOINT is an arbitrary number chosen large enough to  */
+/*   (hopefully) not conflict with user boundary markers.  Make sure that it */
+/*   is small enough to fit into your machine's integer size.                */
+
+#define DEADPOINT -1073741824
+
+/* The next line is used to outsmart some very stupid compilers.  If your    */
+/*   compiler is smarter, feel free to replace the "int" with "void".        */
+/*   Not that it matters.                                                    */
+
+#define VOID int
+
+/* Two constants for algorithms based on random sampling.  Both constants    */
+/*   have been chosen empirically to optimize their respective algorithms.   */
+
+/* Used for the point location scheme of Mucke, Saias, and Zhu, to decide    */
+/*   how large a random sample of triangles to inspect.                      */
+#define SAMPLEFACTOR 11
+/* Used in Fortune's sweepline Delaunay algorithm to determine what fraction */
+/*   of boundary edges should be maintained in the splay tree for point      */
+/*   location on the front.                                                  */
+#define SAMPLERATE 10
+
+/* A number that speaks for itself, every kissable digit.                    */
+
+#define PI 3.141592653589793238462643383279502884197169399375105820974944592308
+
+/* Another fave.                                                             */
+
+#define SQUAREROOTTWO 1.4142135623730950488016887242096980785696718753769480732
+
+/* And here's one for those of you who are intimidated by math.              */
+
+#define ONETHIRD 0.333333333333333333333333333333333333333333333333333333333333
+
+#include <stdio.h>
+#include <string.h>
+#include <math.h>
+#ifndef NO_TIMER
+#include <sys/time.h>
+#endif /* NO_TIMER */
+#ifdef TRILIBRARY
+#include "triangle.h"
+#endif /* TRILIBRARY */
+
+/* The following obscenity seems to be necessary to ensure that this program */
+/* will port to Dec Alphas running OSF/1, because their stdio.h file commits */
+/* the unpardonable sin of including stdlib.h.  Hence, malloc(), free(), and */
+/* exit() may or may not already be defined at this point.  I declare these  */
+/* functions explicitly because some non-ANSI C compilers lack stdlib.h.     */
+
+#ifndef _STDLIB_H_
+extern void *malloc();
+extern void free();
+extern void exit();
+extern double strtod();
+extern long strtol();
+#endif /* _STDLIB_H_ */
+
+/* A few forward declarations.                                               */
+
+void poolrestart();
+#ifndef TRILIBRARY
+char *readline();
+char *findfield();
+#endif /* not TRILIBRARY */
+
+/* Labels that signify whether a record consists primarily of pointers or of */
+/*   floating-point words.  Used to make decisions about data alignment.     */
+
+enum wordtype {POINTER, FLOATINGPOINT};
+
+/* Labels that signify the result of point location.  The result of a        */
+/*   search indicates that the point falls in the interior of a triangle, on */
+/*   an edge, on a vertex, or outside the mesh.                              */
+
+enum locateresult {INTRIANGLE, ONEDGE, ONVERTEX, OUTSIDE};
+
+/* Labels that signify the result of site insertion.  The result indicates   */
+/*   that the point was inserted with complete success, was inserted but     */
+/*   encroaches on a segment, was not inserted because it lies on a segment, */
+/*   or was not inserted because another point occupies the same location.   */
+
+enum insertsiteresult {SUCCESSFULPOINT, ENCROACHINGPOINT, VIOLATINGPOINT,
+                       DUPLICATEPOINT};
+
+/* Labels that signify the result of direction finding.  The result          */
+/*   indicates that a segment connecting the two query points falls within   */
+/*   the direction triangle, along the left edge of the direction triangle,  */
+/*   or along the right edge of the direction triangle.                      */
+
+enum finddirectionresult {WITHIN, LEFTCOLLINEAR, RIGHTCOLLINEAR};
+
+/* Labels that signify the result of the circumcenter computation routine.   */
+/*   The return value indicates which edge of the triangle is shortest.      */
+
+enum circumcenterresult {OPPOSITEORG, OPPOSITEDEST, OPPOSITEAPEX};
+
+/*****************************************************************************/
+/*                                                                           */
+/*  The basic mesh data structures                                           */
+/*                                                                           */
+/*  There are three:  points, triangles, and shell edges (abbreviated        */
+/*  `shelle').  These three data structures, linked by pointers, comprise    */
+/*  the mesh.  A point simply represents a point in space and its properties.*/
+/*  A triangle is a triangle.  A shell edge is a special data structure used */
+/*  to represent impenetrable segments in the mesh (including the outer      */
+/*  boundary, boundaries of holes, and internal boundaries separating two    */
+/*  triangulated regions).  Shell edges represent boundaries defined by the  */
+/*  user that triangles may not lie across.                                  */
+/*                                                                           */
+/*  A triangle consists of a list of three vertices, a list of three         */
+/*  adjoining triangles, a list of three adjoining shell edges (when shell   */
+/*  edges are used), an arbitrary number of optional user-defined floating-  */
+/*  point attributes, and an optional area constraint.  The latter is an     */
+/*  upper bound on the permissible area of each triangle in a region, used   */
+/*  for mesh refinement.                                                     */
+/*                                                                           */
+/*  For a triangle on a boundary of the mesh, some or all of the neighboring */
+/*  triangles may not be present.  For a triangle in the interior of the     */
+/*  mesh, often no neighboring shell edges are present.  Such absent         */
+/*  triangles and shell edges are never represented by NULL pointers; they   */
+/*  are represented by two special records:  `dummytri', the triangle that   */
+/*  fills "outer space", and `dummysh', the omnipresent shell edge.          */
+/*  `dummytri' and `dummysh' are used for several reasons; for instance,     */
+/*  they can be dereferenced and their contents examined without causing the */
+/*  memory protection exception that would occur if NULL were dereferenced.  */
+/*                                                                           */
+/*  However, it is important to understand that a triangle includes other    */
+/*  information as well.  The pointers to adjoining vertices, triangles, and */
+/*  shell edges are ordered in a way that indicates their geometric relation */
+/*  to each other.  Furthermore, each of these pointers contains orientation */
+/*  information.  Each pointer to an adjoining triangle indicates which face */
+/*  of that triangle is contacted.  Similarly, each pointer to an adjoining  */
+/*  shell edge indicates which side of that shell edge is contacted, and how */
+/*  the shell edge is oriented relative to the triangle.                     */
+/*                                                                           */
+/*  Shell edges are found abutting edges of triangles; either sandwiched     */
+/*  between two triangles, or resting against one triangle on an exterior    */
+/*  boundary or hole boundary.                                               */
+/*                                                                           */
+/*  A shell edge consists of a list of two vertices, a list of two           */
+/*  adjoining shell edges, and a list of two adjoining triangles.  One of    */
+/*  the two adjoining triangles may not be present (though there should      */
+/*  always be one), and neighboring shell edges might not be present.        */
+/*  Shell edges also store a user-defined integer "boundary marker".         */
+/*  Typically, this integer is used to indicate what sort of boundary        */
+/*  conditions are to be applied at that location in a finite element        */
+/*  simulation.                                                              */
+/*                                                                           */
+/*  Like triangles, shell edges maintain information about the relative      */
+/*  orientation of neighboring objects.                                      */
+/*                                                                           */
+/*  Points are relatively simple.  A point is a list of floating point       */
+/*  numbers, starting with the x, and y coordinates, followed by an          */
+/*  arbitrary number of optional user-defined floating-point attributes,     */
+/*  followed by an integer boundary marker.  During the segment insertion    */
+/*  phase, there is also a pointer from each point to a triangle that may    */
+/*  contain it.  Each pointer is not always correct, but when one is, it     */
+/*  speeds up segment insertion.  These pointers are assigned values once    */
+/*  at the beginning of the segment insertion phase, and are not used or     */
+/*  updated at any other time.  Edge swapping during segment insertion will  */
+/*  render some of them incorrect.  Hence, don't rely upon them for          */
+/*  anything.  For the most part, points do not have any information about   */
+/*  what triangles or shell edges they are linked to.                        */
+/*                                                                           */
+/*****************************************************************************/
+
+/*****************************************************************************/
+/*                                                                           */
+/*  Handles                                                                  */
+/*                                                                           */
+/*  The oriented triangle (`triedge') and oriented shell edge (`edge') data  */
+/*  structures defined below do not themselves store any part of the mesh.   */
+/*  The mesh itself is made of `triangle's, `shelle's, and `point's.         */
+/*                                                                           */
+/*  Oriented triangles and oriented shell edges will usually be referred to  */
+/*  as "handles".  A handle is essentially a pointer into the mesh; it       */
+/*  allows you to "hold" one particular part of the mesh.  Handles are used  */
+/*  to specify the regions in which one is traversing and modifying the mesh.*/
+/*  A single `triangle' may be held by many handles, or none at all.  (The   */
+/*  latter case is not a memory leak, because the triangle is still          */
+/*  connected to other triangles in the mesh.)                               */
+/*                                                                           */
+/*  A `triedge' is a handle that holds a triangle.  It holds a specific side */
+/*  of the triangle.  An `edge' is a handle that holds a shell edge.  It     */
+/*  holds either the left or right side of the edge.                         */
+/*                                                                           */
+/*  Navigation about the mesh is accomplished through a set of mesh          */
+/*  manipulation primitives, further below.  Many of these primitives take   */
+/*  a handle and produce a new handle that holds the mesh near the first     */
+/*  handle.  Other primitives take two handles and glue the corresponding    */
+/*  parts of the mesh together.  The exact position of the handles is        */
+/*  important.  For instance, when two triangles are glued together by the   */
+/*  bond() primitive, they are glued by the sides on which the handles lie.  */
+/*                                                                           */
+/*  Because points have no information about which triangles they are        */
+/*  attached to, I commonly represent a point by use of a handle whose       */
+/*  origin is the point.  A single handle can simultaneously represent a     */
+/*  triangle, an edge, and a point.                                          */
+/*                                                                           */
+/*****************************************************************************/
+
+/* The triangle data structure.  Each triangle contains three pointers to    */
+/*   adjoining triangles, plus three pointers to vertex points, plus three   */
+/*   pointers to shell edges (defined below; these pointers are usually      */
+/*   `dummysh').  It may or may not also contain user-defined attributes     */
+/*   and/or a floating-point "area constraint".  It may also contain extra   */
+/*   pointers for nodes, when the user asks for high-order elements.         */
+/*   Because the size and structure of a `triangle' is not decided until     */
+/*   runtime, I haven't simply defined the type `triangle' to be a struct.   */
+
+typedef REAL **triangle;            /* Really:  typedef triangle *triangle   */
+
+/* An oriented triangle:  includes a pointer to a triangle and orientation.  */
+/*   The orientation denotes an edge of the triangle.  Hence, there are      */
+/*   three possible orientations.  By convention, each edge is always        */
+/*   directed to point counterclockwise about the corresponding triangle.    */
+
+struct triedge {
+  triangle *tri;
+  int orient;                                         /* Ranges from 0 to 2. */
+};
+
+/* The shell data structure.  Each shell edge contains two pointers to       */
+/*   adjoining shell edges, plus two pointers to vertex points, plus two     */
+/*   pointers to adjoining triangles, plus one shell marker.                 */
+
+typedef REAL **shelle;                  /* Really:  typedef shelle *shelle   */
+
+/* An oriented shell edge:  includes a pointer to a shell edge and an        */
+/*   orientation.  The orientation denotes a side of the edge.  Hence, there */
+/*   are two possible orientations.  By convention, the edge is always       */
+/*   directed so that the "side" denoted is the right side of the edge.      */
+
+struct edge {
+  shelle *sh;
+  int shorient;                                       /* Ranges from 0 to 1. */
+};
+
+/* The point data structure.  Each point is actually an array of REALs.      */
+/*   The number of REALs is unknown until runtime.  An integer boundary      */
+/*   marker, and sometimes a pointer to a triangle, is appended after the    */
+/*   REALs.                                                                  */
+
+typedef REAL *point;
+
+/* A queue used to store encroached segments.  Each segment's vertices are   */
+/*   stored so that one can check whether a segment is still the same.       */
+
+struct badsegment {
+  struct edge encsegment;                          /* An encroached segment. */
+  point segorg, segdest;                                /* The two vertices. */
+  struct badsegment *nextsegment;     /* Pointer to next encroached segment. */
+};
+
+/* A queue used to store bad triangles.  The key is the square of the cosine */
+/*   of the smallest angle of the triangle.  Each triangle's vertices are    */
+/*   stored so that one can check whether a triangle is still the same.      */
+
+struct badface {
+  struct triedge badfacetri;                              /* A bad triangle. */
+  REAL key;                             /* cos^2 of smallest (apical) angle. */
+  point faceorg, facedest, faceapex;                  /* The three vertices. */
+  struct badface *nextface;                 /* Pointer to next bad triangle. */
+};
+
+/* A node in a heap used to store events for the sweepline Delaunay          */
+/*   algorithm.  Nodes do not point directly to their parents or children in */
+/*   the heap.  Instead, each node knows its position in the heap, and can   */
+/*   look up its parent and children in a separate array.  The `eventptr'    */
+/*   points either to a `point' or to a triangle (in encoded format, so that */
+/*   an orientation is included).  In the latter case, the origin of the     */
+/*   oriented triangle is the apex of a "circle event" of the sweepline      */
+/*   algorithm.  To distinguish site events from circle events, all circle   */
+/*   events are given an invalid (smaller than `xmin') x-coordinate `xkey'.  */
+
+struct event {
+  REAL xkey, ykey;                              /* Coordinates of the event. */
+  VOID *eventptr;       /* Can be a point or the location of a circle event. */
+  int heapposition;              /* Marks this event's position in the heap. */
+};
+
+/* A node in the splay tree.  Each node holds an oriented ghost triangle     */
+/*   that represents a boundary edge of the growing triangulation.  When a   */
+/*   circle event covers two boundary edges with a triangle, so that they    */
+/*   are no longer boundary edges, those edges are not immediately deleted   */
+/*   from the tree; rather, they are lazily deleted when they are next       */
+/*   encountered.  (Since only a random sample of boundary edges are kept    */
+/*   in the tree, lazy deletion is faster.)  `keydest' is used to verify     */
+/*   that a triangle is still the same as when it entered the splay tree; if */
+/*   it has been rotated (due to a circle event), it no longer represents a  */
+/*   boundary edge and should be deleted.                                    */
+
+struct splaynode {
+  struct triedge keyedge;                  /* Lprev of an edge on the front. */
+  point keydest;            /* Used to verify that splay node is still live. */
+  struct splaynode *lchild, *rchild;              /* Children in splay tree. */
+};
+
+/* A type used to allocate memory.  firstblock is the first block of items.  */
+/*   nowblock is the block from which items are currently being allocated.   */
+/*   nextitem points to the next slab of free memory for an item.            */
+/*   deaditemstack is the head of a linked list (stack) of deallocated items */
+/*   that can be recycled.  unallocateditems is the number of items that     */
+/*   remain to be allocated from nowblock.                                   */
+/*                                                                           */
+/* Traversal is the process of walking through the entire list of items, and */
+/*   is separate from allocation.  Note that a traversal will visit items on */
+/*   the "deaditemstack" stack as well as live items.  pathblock points to   */
+/*   the block currently being traversed.  pathitem points to the next item  */
+/*   to be traversed.  pathitemsleft is the number of items that remain to   */
+/*   be traversed in pathblock.                                              */
+/*                                                                           */
+/* itemwordtype is set to POINTER or FLOATINGPOINT, and is used to suggest   */
+/*   what sort of word the record is primarily made up of.  alignbytes       */
+/*   determines how new records should be aligned in memory.  itembytes and  */
+/*   itemwords are the length of a record in bytes (after rounding up) and   */
+/*   words.  itemsperblock is the number of items allocated at once in a     */
+/*   single block.  items is the number of currently allocated items.        */
+/*   maxitems is the maximum number of items that have been allocated at     */
+/*   once; it is the current number of items plus the number of records kept */
+/*   on deaditemstack.                                                       */
+
+struct memorypool {
+  VOID **firstblock, **nowblock;
+  VOID *nextitem;
+  VOID *deaditemstack;
+  VOID **pathblock;
+  VOID *pathitem;
+  enum wordtype itemwordtype;
+  int alignbytes;
+  int itembytes, itemwords;
+  int itemsperblock;
+  long items, maxitems;
+  int unallocateditems;
+  int pathitemsleft;
+};
+
+/* Variables used to allocate memory for triangles, shell edges, points,     */
+/*   viri (triangles being eaten), bad (encroached) segments, bad (skinny    */
+/*   or too large) triangles, and splay tree nodes.                          */
+
+struct memorypool triangles;
+struct memorypool shelles;
+struct memorypool points;
+struct memorypool viri;
+struct memorypool badsegments;
+struct memorypool badtriangles;
+struct memorypool splaynodes;
+
+/* Variables that maintain the bad triangle queues.  The tails are pointers  */
+/*   to the pointers that have to be filled in to enqueue an item.           */
+
+struct badface *queuefront[64];
+struct badface **queuetail[64];
+
+REAL xmin, xmax, ymin, ymax;                              /* x and y bounds. */
+REAL xminextreme;        /* Nonexistent x value used as a flag in sweepline. */
+int inpoints;                                     /* Number of input points. */
+int inelements;                                /* Number of input triangles. */
+int insegments;                                 /* Number of input segments. */
+int holes;                                         /* Number of input holes. */
+int regions;                                     /* Number of input regions. */
+long edges;                                       /* Number of output edges. */
+int mesh_dim;                                  /* Dimension (ought to be 2). */
+int nextras;                              /* Number of attributes per point. */
+int eextras;                           /* Number of attributes per triangle. */
+long hullsize;                            /* Number of edges of convex hull. */
+int triwords;                                   /* Total words per triangle. */
+int shwords;                                  /* Total words per shell edge. */
+int pointmarkindex;             /* Index to find boundary marker of a point. */
+int point2triindex;         /* Index to find a triangle adjacent to a point. */
+int highorderindex;    /* Index to find extra nodes for high-order elements. */
+int elemattribindex;              /* Index to find attributes of a triangle. */
+int areaboundindex;               /* Index to find area bound of a triangle. */
+int checksegments;           /* Are there segments in the triangulation yet? */
+int readnodefile;                             /* Has a .node file been read? */
+long samples;                /* Number of random samples for point location. */
+unsigned long randomseed;                     /* Current random number seed. */
+
+REAL splitter;       /* Used to split REAL factors for exact multiplication. */
+REAL epsilon;                             /* Floating-point machine epsilon. */
+REAL resulterrbound;
+REAL ccwerrboundA, ccwerrboundB, ccwerrboundC;
+REAL iccerrboundA, iccerrboundB, iccerrboundC;
+
+long incirclecount;                   /* Number of incircle tests performed. */
+long counterclockcount;       /* Number of counterclockwise tests performed. */
+long hyperbolacount;        /* Number of right-of-hyperbola tests performed. */
+long circumcentercount;    /* Number of circumcenter calculations performed. */
+long circletopcount;         /* Number of circle top calculations performed. */
+
+/* Switches for the triangulator.                                            */
+/*   poly: -p switch.  refine: -r switch.                                    */
+/*   quality: -q switch.                                                     */
+/*     minangle: minimum angle bound, specified after -q switch.             */
+/*     goodangle: cosine squared of minangle.                                */
+/*   vararea: -a switch without number.                                      */
+/*   fixedarea: -a switch with number.                                       */
+/*     maxarea: maximum area bound, specified after -a switch.               */
+/*   regionattrib: -A switch.  convex: -c switch.                            */
+/*   firstnumber: inverse of -z switch.  All items are numbered starting     */
+/*     from firstnumber.                                                     */
+/*   edgesout: -e switch.  voronoi: -v switch.                               */
+/*   neighbors: -n switch.  geomview: -g switch.                             */
+/*   nobound: -B switch.  nopolywritten: -P switch.                          */
+/*   nonodewritten: -N switch.  noelewritten: -E switch.                     */
+/*   noiterationnum: -I switch.  noholes: -O switch.                         */
+/*   noexact: -X switch.                                                     */
+/*   order: element order, specified after -o switch.                        */
+/*   nobisect: count of how often -Y switch is selected.                     */
+/*   steiner: maximum number of Steiner points, specified after -S switch.   */
+/*     steinerleft: number of Steiner points not yet used.                   */
+/*   incremental: -i switch.  sweepline: -F switch.                          */
+/*   dwyer: inverse of -l switch.                                            */
+/*   splitseg: -s switch.                                                    */
+/*   docheck: -C switch.                                                     */
+/*   quiet: -Q switch.  verbose: count of how often -V switch is selected.   */
+/*   useshelles: -p, -r, -q, or -c switch; determines whether shell edges    */
+/*     are used at all.                                                      */
+/*                                                                           */
+/* Read the instructions to find out the meaning of these switches.          */
+
+int poly, refine, quality, vararea, fixedarea, regionattrib, convex;
+int firstnumber;
+int edgesout, voronoi, neighbors, geomview;
+int nobound, nopolywritten, nonodewritten, noelewritten, noiterationnum;
+int noholes, noexact;
+int incremental, sweepline, dwyer;
+int splitseg;
+int docheck;
+int quiet, verbose;
+int useshelles;
+int order;
+int nobisect;
+int steiner, steinerleft;
+REAL minangle, goodangle;
+REAL maxarea;
+
+/* Variables for file names.                                                 */
+
+#ifndef TRILIBRARY
+char innodefilename[FILENAMESIZE];
+char inelefilename[FILENAMESIZE];
+char inpolyfilename[FILENAMESIZE];
+char areafilename[FILENAMESIZE];
+char outnodefilename[FILENAMESIZE];
+char outelefilename[FILENAMESIZE];
+char outpolyfilename[FILENAMESIZE];
+char edgefilename[FILENAMESIZE];
+char vnodefilename[FILENAMESIZE];
+char vedgefilename[FILENAMESIZE];
+char neighborfilename[FILENAMESIZE];
+char offfilename[FILENAMESIZE];
+#endif /* not TRILIBRARY */
+
+/* Triangular bounding box points.                                           */
+
+point infpoint1, infpoint2, infpoint3;
+
+/* Pointer to the `triangle' that occupies all of "outer space".             */
+
+triangle *dummytri;
+triangle *dummytribase;      /* Keep base address so we can free() it later. */
+
+/* Pointer to the omnipresent shell edge.  Referenced by any triangle or     */
+/*   shell edge that isn't really connected to a shell edge at that          */
+/*   location.                                                               */
+
+shelle *dummysh;
+shelle *dummyshbase;         /* Keep base address so we can free() it later. */
+
+/* Pointer to a recently visited triangle.  Improves point location if       */
+/*   proximate points are inserted sequentially.                             */
+
+struct triedge recenttri;
+
+/*****************************************************************************/
+/*                                                                           */
+/*  Mesh manipulation primitives.  Each triangle contains three pointers to  */
+/*  other triangles, with orientations.  Each pointer points not to the      */
+/*  first byte of a triangle, but to one of the first three bytes of a       */
+/*  triangle.  It is necessary to extract both the triangle itself and the   */
+/*  orientation.  To save memory, I keep both pieces of information in one   */
+/*  pointer.  To make this possible, I assume that all triangles are aligned */
+/*  to four-byte boundaries.  The `decode' routine below decodes a pointer,  */
+/*  extracting an orientation (in the range 0 to 2) and a pointer to the     */
+/*  beginning of a triangle.  The `encode' routine compresses a pointer to a */
+/*  triangle and an orientation into a single pointer.  My assumptions that  */
+/*  triangles are four-byte-aligned and that the `unsigned long' type is     */
+/*  long enough to hold a pointer are two of the few kludges in this program.*/
+/*                                                                           */
+/*  Shell edges are manipulated similarly.  A pointer to a shell edge        */
+/*  carries both an address and an orientation in the range 0 to 1.          */
+/*                                                                           */
+/*  The other primitives take an oriented triangle or oriented shell edge,   */
+/*  and return an oriented triangle or oriented shell edge or point; or they */
+/*  change the connections in the data structure.                            */
+/*                                                                           */
+/*****************************************************************************/
+
+/********* Mesh manipulation primitives begin here                   *********/
+/**                                                                         **/
+/**                                                                         **/
+
+/* Fast lookup arrays to speed some of the mesh manipulation primitives.     */
+
+int plus1mod3[3] = {1, 2, 0};
+int minus1mod3[3] = {2, 0, 1};
+
+/********* Primitives for triangles                                  *********/
+/*                                                                           */
+/*                                                                           */
+
+/* decode() converts a pointer to an oriented triangle.  The orientation is  */
+/*   extracted from the two least significant bits of the pointer.           */
+
+#define decode(ptr, triedge)                                                  \
+  (triedge).orient = (int) ((unsigned long) (ptr) & (unsigned long) 3l);      \
+  (triedge).tri = (triangle *)                                                \
+                  ((unsigned long) (ptr) ^ (unsigned long) (triedge).orient)
+
+/* encode() compresses an oriented triangle into a single pointer.  It       */
+/*   relies on the assumption that all triangles are aligned to four-byte    */
+/*   boundaries, so the two least significant bits of (triedge).tri are zero.*/
+
+#define encode(triedge)                                                       \
+  (triangle) ((unsigned long) (triedge).tri | (unsigned long) (triedge).orient)
+
+/* The following edge manipulation primitives are all described by Guibas    */
+/*   and Stolfi.  However, they use an edge-based data structure, whereas I  */
+/*   am using a triangle-based data structure.                               */
+
+/* sym() finds the abutting triangle, on the same edge.  Note that the       */
+/*   edge direction is necessarily reversed, because triangle/edge handles   */
+/*   are always directed counterclockwise around the triangle.               */
+
+#define sym(triedge1, triedge2)                                               \
+  ptr = (triedge1).tri[(triedge1).orient];                                    \
+  decode(ptr, triedge2);
+
+#define symself(triedge)                                                      \
+  ptr = (triedge).tri[(triedge).orient];                                      \
+  decode(ptr, triedge);
+
+/* lnext() finds the next edge (counterclockwise) of a triangle.             */
+
+#define lnext(triedge1, triedge2)                                             \
+  (triedge2).tri = (triedge1).tri;                                            \
+  (triedge2).orient = plus1mod3[(triedge1).orient]
+
+#define lnextself(triedge)                                                    \
+  (triedge).orient = plus1mod3[(triedge).orient]
+
+/* lprev() finds the previous edge (clockwise) of a triangle.                */
+
+#define lprev(triedge1, triedge2)                                             \
+  (triedge2).tri = (triedge1).tri;                                            \
+  (triedge2).orient = minus1mod3[(triedge1).orient]
+
+#define lprevself(triedge)                                                    \
+  (triedge).orient = minus1mod3[(triedge).orient]
+
+/* onext() spins counterclockwise around a point; that is, it finds the next */
+/*   edge with the same origin in the counterclockwise direction.  This edge */
+/*   will be part of a different triangle.                                   */
+
+#define onext(triedge1, triedge2)                                             \
+  lprev(triedge1, triedge2);                                                  \
+  symself(triedge2);
+
+#define onextself(triedge)                                                    \
+  lprevself(triedge);                                                         \
+  symself(triedge);
+
+/* oprev() spins clockwise around a point; that is, it finds the next edge   */
+/*   with the same origin in the clockwise direction.  This edge will be     */
+/*   part of a different triangle.                                           */
+
+#define oprev(triedge1, triedge2)                                             \
+  sym(triedge1, triedge2);                                                    \
+  lnextself(triedge2);
+
+#define oprevself(triedge)                                                    \
+  symself(triedge);                                                           \
+  lnextself(triedge);
+
+/* dnext() spins counterclockwise around a point; that is, it finds the next */
+/*   edge with the same destination in the counterclockwise direction.  This */
+/*   edge will be part of a different triangle.                              */
+
+#define dnext(triedge1, triedge2)                                             \
+  sym(triedge1, triedge2);                                                    \
+  lprevself(triedge2);
+
+#define dnextself(triedge)                                                    \
+  symself(triedge);                                                           \
+  lprevself(triedge);
+
+/* dprev() spins clockwise around a point; that is, it finds the next edge   */
+/*   with the same destination in the clockwise direction.  This edge will   */
+/*   be part of a different triangle.                                        */
+
+#define dprev(triedge1, triedge2)                                             \
+  lnext(triedge1, triedge2);                                                  \
+  symself(triedge2);
+
+#define dprevself(triedge)                                                    \
+  lnextself(triedge);                                                         \
+  symself(triedge);
+
+/* rnext() moves one edge counterclockwise about the adjacent triangle.      */
+/*   (It's best understood by reading Guibas and Stolfi.  It involves        */
+/*   changing triangles twice.)                                              */
+
+#define rnext(triedge1, triedge2)                                             \
+  sym(triedge1, triedge2);                                                    \
+  lnextself(triedge2);                                                        \
+  symself(triedge2);
+
+#define rnextself(triedge)                                                    \
+  symself(triedge);                                                           \
+  lnextself(triedge);                                                         \
+  symself(triedge);
+
+/* rnext() moves one edge clockwise about the adjacent triangle.             */
+/*   (It's best understood by reading Guibas and Stolfi.  It involves        */
+/*   changing triangles twice.)                                              */
+
+#define rprev(triedge1, triedge2)                                             \
+  sym(triedge1, triedge2);                                                    \
+  lprevself(triedge2);                                                        \
+  symself(triedge2);
+
+#define rprevself(triedge)                                                    \
+  symself(triedge);                                                           \
+  lprevself(triedge);                                                         \
+  symself(triedge);
+
+/* These primitives determine or set the origin, destination, or apex of a   */
+/* triangle.                                                                 */
+
+#define org(triedge, pointptr)                                                \
+  pointptr = (point) (triedge).tri[plus1mod3[(triedge).orient] + 3]
+
+#define dest(triedge, pointptr)                                               \
+  pointptr = (point) (triedge).tri[minus1mod3[(triedge).orient] + 3]
+
+#define apex(triedge, pointptr)                                               \
+  pointptr = (point) (triedge).tri[(triedge).orient + 3]
+
+#define setorg(triedge, pointptr)                                             \
+  (triedge).tri[plus1mod3[(triedge).orient] + 3] = (triangle) pointptr
+
+#define setdest(triedge, pointptr)                                            \
+  (triedge).tri[minus1mod3[(triedge).orient] + 3] = (triangle) pointptr
+
+#define setapex(triedge, pointptr)                                            \
+  (triedge).tri[(triedge).orient + 3] = (triangle) pointptr
+
+#define setvertices2null(triedge)                                             \
+  (triedge).tri[3] = (triangle) NULL;                                         \
+  (triedge).tri[4] = (triangle) NULL;                                         \
+  (triedge).tri[5] = (triangle) NULL;
+
+/* Bond two triangles together.                                              */
+
+#define bond(triedge1, triedge2)                                              \
+  (triedge1).tri[(triedge1).orient] = encode(triedge2);                       \
+  (triedge2).tri[(triedge2).orient] = encode(triedge1)
+
+/* Dissolve a bond (from one side).  Note that the other triangle will still */
+/*   think it's connected to this triangle.  Usually, however, the other     */
+/*   triangle is being deleted entirely, or bonded to another triangle, so   */
+/*   it doesn't matter.                                                      */
+
+#define dissolve(triedge)                                                     \
+  (triedge).tri[(triedge).orient] = (triangle) dummytri
+
+/* Copy a triangle/edge handle.                                              */
+
+#define triedgecopy(triedge1, triedge2)                                       \
+  (triedge2).tri = (triedge1).tri;                                            \
+  (triedge2).orient = (triedge1).orient
+
+/* Test for equality of triangle/edge handles.                               */
+
+#define triedgeequal(triedge1, triedge2)                                      \
+  (((triedge1).tri == (triedge2).tri) &&                                      \
+   ((triedge1).orient == (triedge2).orient))
+
+/* Primitives to infect or cure a triangle with the virus.  These rely on    */
+/*   the assumption that all shell edges are aligned to four-byte boundaries.*/
+
+#define infect(triedge)                                                       \
+  (triedge).tri[6] = (triangle)                                               \
+                     ((unsigned long) (triedge).tri[6] | (unsigned long) 2l)
+
+#define uninfect(triedge)                                                     \
+  (triedge).tri[6] = (triangle)                                               \
+                     ((unsigned long) (triedge).tri[6] & ~ (unsigned long) 2l)
+
+/* Test a triangle for viral infection.                                      */
+
+#define infected(triedge)                                                     \
+  (((unsigned long) (triedge).tri[6] & (unsigned long) 2l) != 0)
+
+/* Check or set a triangle's attributes.                                     */
+
+#define elemattribute(triedge, attnum)                                        \
+  ((REAL *) (triedge).tri)[elemattribindex + (attnum)]
+
+#define setelemattribute(triedge, attnum, value)                              \
+  ((REAL *) (triedge).tri)[elemattribindex + (attnum)] = value
+
+/* Check or set a triangle's maximum area bound.                             */
+
+#define areabound(triedge)  ((REAL *) (triedge).tri)[areaboundindex]
+
+#define setareabound(triedge, value)                                          \
+  ((REAL *) (triedge).tri)[areaboundindex] = value
+
+/********* Primitives for shell edges                                *********/
+/*                                                                           */
+/*                                                                           */
+
+/* sdecode() converts a pointer to an oriented shell edge.  The orientation  */
+/*   is extracted from the least significant bit of the pointer.  The two    */
+/*   least significant bits (one for orientation, one for viral infection)   */
+/*   are masked out to produce the real pointer.                             */
+
+#define sdecode(sptr, edge)                                                   \
+  (edge).shorient = (int) ((unsigned long) (sptr) & (unsigned long) 1l);      \
+  (edge).sh = (shelle *)                                                      \
+              ((unsigned long) (sptr) & ~ (unsigned long) 3l)
+
+/* sencode() compresses an oriented shell edge into a single pointer.  It    */
+/*   relies on the assumption that all shell edges are aligned to two-byte   */
+/*   boundaries, so the least significant bit of (edge).sh is zero.          */
+
+#define sencode(edge)                                                         \
+  (shelle) ((unsigned long) (edge).sh | (unsigned long) (edge).shorient)
+
+/* ssym() toggles the orientation of a shell edge.                           */
+
+#define ssym(edge1, edge2)                                                    \
+  (edge2).sh = (edge1).sh;                                                    \
+  (edge2).shorient = 1 - (edge1).shorient
+
+#define ssymself(edge)                                                        \
+  (edge).shorient = 1 - (edge).shorient
+
+/* spivot() finds the other shell edge (from the same segment) that shares   */
+/*   the same origin.                                                        */
+
+#define spivot(edge1, edge2)                                                  \
+  sptr = (edge1).sh[(edge1).shorient];                                        \
+  sdecode(sptr, edge2)
+
+#define spivotself(edge)                                                      \
+  sptr = (edge).sh[(edge).shorient];                                          \
+  sdecode(sptr, edge)
+
+/* snext() finds the next shell edge (from the same segment) in sequence;    */
+/*   one whose origin is the input shell edge's destination.                 */
+
+#define snext(edge1, edge2)                                                   \
+  sptr = (edge1).sh[1 - (edge1).shorient];                                    \
+  sdecode(sptr, edge2)
+
+#define snextself(edge)                                                       \
+  sptr = (edge).sh[1 - (edge).shorient];                                      \
+  sdecode(sptr, edge)
+
+/* These primitives determine or set the origin or destination of a shell    */
+/*   edge.                                                                   */
+
+#define sorg(edge, pointptr)                                                  \
+  pointptr = (point) (edge).sh[2 + (edge).shorient]
+
+#define sdest(edge, pointptr)                                                 \
+  pointptr = (point) (edge).sh[3 - (edge).shorient]
+
+#define setsorg(edge, pointptr)                                               \
+  (edge).sh[2 + (edge).shorient] = (shelle) pointptr
+
+#define setsdest(edge, pointptr)                                              \
+  (edge).sh[3 - (edge).shorient] = (shelle) pointptr
+
+/* These primitives read or set a shell marker.  Shell markers are used to   */
+/*   hold user boundary information.                                         */
+
+#define mark(edge)  (* (int *) ((edge).sh + 6))
+
+#define setmark(edge, value)                                                  \
+  * (int *) ((edge).sh + 6) = value
+
+/* Bond two shell edges together.                                            */
+
+#define sbond(edge1, edge2)                                                   \
+  (edge1).sh[(edge1).shorient] = sencode(edge2);                              \
+  (edge2).sh[(edge2).shorient] = sencode(edge1)
+
+/* Dissolve a shell edge bond (from one side).  Note that the other shell    */
+/*   edge will still think it's connected to this shell edge.                */
+
+#define sdissolve(edge)                                                       \
+  (edge).sh[(edge).shorient] = (shelle) dummysh
+
+/* Copy a shell edge.                                                        */
+
+#define shellecopy(edge1, edge2)                                              \
+  (edge2).sh = (edge1).sh;                                                    \
+  (edge2).shorient = (edge1).shorient
+
+/* Test for equality of shell edges.                                         */
+
+#define shelleequal(edge1, edge2)                                             \
+  (((edge1).sh == (edge2).sh) &&                                              \
+   ((edge1).shorient == (edge2).shorient))
+
+/********* Primitives for interacting triangles and shell edges      *********/
+/*                                                                           */
+/*                                                                           */
+
+/* tspivot() finds a shell edge abutting a triangle.                         */
+
+#define tspivot(triedge, edge)                                                \
+  sptr = (shelle) (triedge).tri[6 + (triedge).orient];                        \
+  sdecode(sptr, edge)
+
+/* stpivot() finds a triangle abutting a shell edge.  It requires that the   */
+/*   variable `ptr' of type `triangle' be defined.                           */
+
+#define stpivot(edge, triedge)                                                \
+  ptr = (triangle) (edge).sh[4 + (edge).shorient];                            \
+  decode(ptr, triedge)
+
+/* Bond a triangle to a shell edge.                                          */
+
+#define tsbond(triedge, edge)                                                 \
+  (triedge).tri[6 + (triedge).orient] = (triangle) sencode(edge);             \
+  (edge).sh[4 + (edge).shorient] = (shelle) encode(triedge)
+
+/* Dissolve a bond (from the triangle side).                                 */
+
+#define tsdissolve(triedge)                                                   \
+  (triedge).tri[6 + (triedge).orient] = (triangle) dummysh
+
+/* Dissolve a bond (from the shell edge side).                               */
+
+#define stdissolve(edge)                                                      \
+  (edge).sh[4 + (edge).shorient] = (shelle) dummytri
+
+/********* Primitives for points                                     *********/
+/*                                                                           */
+/*                                                                           */
+
+#define pointmark(pt)  ((int *) (pt))[pointmarkindex]
+
+#define setpointmark(pt, value)                                               \
+  ((int *) (pt))[pointmarkindex] = value
+
+#define point2tri(pt)  ((triangle *) (pt))[point2triindex]
+
+#define setpoint2tri(pt, value)                                               \
+  ((triangle *) (pt))[point2triindex] = value
+
+/**                                                                         **/
+/**                                                                         **/
+/********* Mesh manipulation primitives end here                     *********/
+
+/********* User interaction routines begin here                      *********/
+/**                                                                         **/
+/**                                                                         **/
+
+/*****************************************************************************/
+/*                                                                           */
+/*  syntax()   Print list of command line switches.                          */
+/*                                                                           */
+/*****************************************************************************/
+
+#ifndef TRILIBRARY
+
+void syntax()
+{
+#ifdef CDT_ONLY
+#ifdef REDUCED
+  printf("triangle [-pAcevngBPNEIOXzo_lQVh] input_file\n");
+#else /* not REDUCED */
+  printf("triangle [-pAcevngBPNEIOXzo_iFlCQVh] input_file\n");
+#endif /* not REDUCED */
+#else /* not CDT_ONLY */
+#ifdef REDUCED
+  printf("triangle [-prq__a__AcevngBPNEIOXzo_YS__lQVh] input_file\n");
+#else /* not REDUCED */
+  printf("triangle [-prq__a__AcevngBPNEIOXzo_YS__iFlsCQVh] input_file\n");
+#endif /* not REDUCED */
+#endif /* not CDT_ONLY */
+
+  printf("    -p  Triangulates a Planar Straight Line Graph (.poly file).\n");
+#ifndef CDT_ONLY
+  printf("    -r  Refines a previously generated mesh.\n");
+  printf(
+    "    -q  Quality mesh generation.  A minimum angle may be specified.\n");
+  printf("    -a  Applies a maximum triangle area constraint.\n");
+#endif /* not CDT_ONLY */
+  printf(
+    "    -A  Applies attributes to identify elements in certain regions.\n");
+  printf("    -c  Encloses the convex hull with segments.\n");
+  printf("    -e  Generates an edge list.\n");
+  printf("    -v  Generates a Voronoi diagram.\n");
+  printf("    -n  Generates a list of triangle neighbors.\n");
+  printf("    -g  Generates an .off file for Geomview.\n");
+  printf("    -B  Suppresses output of boundary information.\n");
+  printf("    -P  Suppresses output of .poly file.\n");
+  printf("    -N  Suppresses output of .node file.\n");
+  printf("    -E  Suppresses output of .ele file.\n");
+  printf("    -I  Suppresses mesh iteration numbers.\n");
+  printf("    -O  Ignores holes in .poly file.\n");
+  printf("    -X  Suppresses use of exact arithmetic.\n");
+  printf("    -z  Numbers all items starting from zero (rather than one).\n");
+  printf("    -o2 Generates second-order subparametric elements.\n");
+#ifndef CDT_ONLY
+  printf("    -Y  Suppresses boundary segment splitting.\n");
+  printf("    -S  Specifies maximum number of added Steiner points.\n");
+#endif /* not CDT_ONLY */
+#ifndef REDUCED
+  printf("    -i  Uses incremental method, rather than divide-and-conquer.\n");
+  printf("    -F  Uses Fortune's sweepline algorithm, rather than d-and-c.\n");
+#endif /* not REDUCED */
+  printf("    -l  Uses vertical cuts only, rather than alternating cuts.\n");
+#ifndef REDUCED
+#ifndef CDT_ONLY
+  printf(
+    "    -s  Force segments into mesh by splitting (instead of using CDT).\n");
+#endif /* not CDT_ONLY */
+  printf("    -C  Check consistency of final mesh.\n");
+#endif /* not REDUCED */
+  printf("    -Q  Quiet:  No terminal output except errors.\n");
+  printf("    -V  Verbose:  Detailed information on what I'm doing.\n");
+  printf("    -h  Help:  Detailed instructions for Triangle.\n");
+  exit(0);
+}
+
+#endif /* not TRILIBRARY */
+
+/*****************************************************************************/
+/*                                                                           */
+/*  info()   Print out complete instructions.                                */
+/*                                                                           */
+/*****************************************************************************/
+
+#ifndef TRILIBRARY
+
+void info()
+{
+  printf("Triangle\n");
+  printf(
+"A Two-Dimensional Quality Mesh Generator and Delaunay Triangulator.\n");
+  printf("Version 1.3\n\n");
+  printf(
+"Copyright 1996 Jonathan Richard Shewchuk  (bugs/comments to jrs@cs.cmu.edu)\n"
+);
+  printf("School of Computer Science / Carnegie Mellon University\n");
+  printf("5000 Forbes Avenue / Pittsburgh, Pennsylvania  15213-3891\n");
+  printf(
+"Created as part of the Archimedes project (tools for parallel FEM).\n");
+  printf(
+"Supported in part by NSF Grant CMS-9318163 and an NSERC 1967 Scholarship.\n");
+  printf("There is no warranty whatsoever.  Use at your own risk.\n");
+#ifdef SINGLE
+  printf("This executable is compiled for single precision arithmetic.\n\n\n");
+#else /* not SINGLE */
+  printf("This executable is compiled for double precision arithmetic.\n\n\n");
+#endif /* not SINGLE */
+  printf(
+"Triangle generates exact Delaunay triangulations, constrained Delaunay\n");
+  printf(
+"triangulations, and quality conforming Delaunay triangulations.  The latter\n"
+);
+  printf(
+"can be generated with no small angles, and are thus suitable for finite\n");
+  printf(
+"element analysis.  If no command line switches are specified, your .node\n");
+  printf(
+"input file will be read, and the Delaunay triangulation will be returned in\n"
+);
+  printf(".node and .ele output files.  The command syntax is:\n\n");
+#ifdef CDT_ONLY
+#ifdef REDUCED
+  printf("triangle [-pAcevngBPNEIOXzo_lQVh] input_file\n\n");
+#else /* not REDUCED */
+  printf("triangle [-pAcevngBPNEIOXzo_iFlCQVh] input_file\n\n");
+#endif /* not REDUCED */
+#else /* not CDT_ONLY */
+#ifdef REDUCED
+  printf("triangle [-prq__a__AcevngBPNEIOXzo_YS__lQVh] input_file\n\n");
+#else /* not REDUCED */
+  printf("triangle [-prq__a__AcevngBPNEIOXzo_YS__iFlsCQVh] input_file\n\n");
+#endif /* not REDUCED */
+#endif /* not CDT_ONLY */
+  printf(
+"Underscores indicate that numbers may optionally follow certain switches;\n");
+  printf(
+"do not leave any space between a switch and its numeric parameter.\n");
+  printf(
+"input_file must be a file with extension .node, or extension .poly if the\n");
+  printf(
+"-p switch is used.  If -r is used, you must supply .node and .ele files,\n");
+  printf(
+"and possibly a .poly file and .area file as well.  The formats of these\n");
+  printf("files are described below.\n\n");
+  printf("Command Line Switches:\n\n");
+  printf(
+"    -p  Reads a Planar Straight Line Graph (.poly file), which can specify\n"
+);
+  printf(
+"        points, segments, holes, and regional attributes and area\n");
+  printf(
+"        constraints.  Will generate a constrained Delaunay triangulation\n");
+  printf(
+"        fitting the input; or, if -s, -q, or -a is used, a conforming\n");
+  printf(
+"        Delaunay triangulation.  If -p is not used, Triangle reads a .node\n"
+);
+  printf("        file by default.\n");
+  printf(
+"    -r  Refines a previously generated mesh.  The mesh is read from a .node\n"
+);
+  printf(
+"        file and an .ele file.  If -p is also used, a .poly file is read\n");
+  printf(
+"        and used to constrain edges in the mesh.  Further details on\n");
+  printf("        refinement are given below.\n");
+  printf(
+"    -q  Quality mesh generation by Jim Ruppert's Delaunay refinement\n");
+  printf(
+"        algorithm.  Adds points to the mesh to ensure that no angles\n");
+  printf(
+"        smaller than 20 degrees occur.  An alternative minimum angle may be\n"
+);
+  printf(
+"        specified after the `q'.  If the minimum angle is 20.7 degrees or\n");
+  printf(
+"        smaller, the triangulation algorithm is theoretically guaranteed to\n"
+);
+  printf(
+"        terminate (assuming infinite precision arithmetic - Triangle may\n");
+  printf(
+"        fail to terminate if you run out of precision).  In practice, the\n");
+  printf(
+"        algorithm often succeeds for minimum angles up to 33.8 degrees.\n");
+  printf(
+"        For highly refined meshes, however, it may be necessary to reduce\n");
+  printf(
+"        the minimum angle to well below 20 to avoid problems associated\n");
+  printf(
+"        with insufficient floating-point precision.  The specified angle\n");
+  printf("        may include a decimal point.\n");
+  printf(
+"    -a  Imposes a maximum triangle area.  If a number follows the `a', no\n");
+  printf(
+"        triangle will be generated whose area is larger than that number.\n");
+  printf(
+"        If no number is specified, an .area file (if -r is used) or .poly\n");
+  printf(
+"        file (if -r is not used) specifies a number of maximum area\n");
+  printf(
+"        constraints.  An .area file contains a separate area constraint for\n"
+);
+  printf(
+"        each triangle, and is useful for refining a finite element mesh\n");
+  printf(
+"        based on a posteriori error estimates.  A .poly file can optionally\n"
+);
+  printf(
+"        contain an area constraint for each segment-bounded region, thereby\n"
+);
+  printf(
+"        enforcing triangle densities in a first triangulation.  You can\n");
+  printf(
+"        impose both a fixed area constraint and a varying area constraint\n");
+  printf(
+"        by invoking the -a switch twice, once with and once without a\n");
+  printf(
+"        number following.  Each area specified may include a decimal point.\n"
+);
+  printf(
+"    -A  Assigns an additional attribute to each triangle that identifies\n");
+  printf(
+"        what segment-bounded region each triangle belongs to.  Attributes\n");
+  printf(
+"        are assigned to regions by the .poly file.  If a region is not\n");
+  printf(
+"        explicitly marked by the .poly file, triangles in that region are\n");
+  printf(
+"        assigned an attribute of zero.  The -A switch has an effect only\n");
+  printf("        when the -p switch is used and the -r switch is not.\n");
+  printf(
+"    -c  Creates segments on the convex hull of the triangulation.  If you\n");
+  printf(
+"        are triangulating a point set, this switch causes a .poly file to\n");
+  printf(
+"        be written, containing all edges in the convex hull.  (By default,\n"
+);
+  printf(
+"        a .poly file is written only if a .poly file is read.)  If you are\n"
+);
+  printf(
+"        triangulating a PSLG, this switch specifies that the interior of\n");
+  printf(
+"        the convex hull of the PSLG should be triangulated.  If you do not\n"
+);
+  printf(
+"        use this switch when triangulating a PSLG, it is assumed that you\n");
+  printf(
+"        have identified the region to be triangulated by surrounding it\n");
+  printf(
+"        with segments of the input PSLG.  Beware:  if you are not careful,\n"
+);
+  printf(
+"        this switch can cause the introduction of an extremely thin angle\n");
+  printf(
+"        between a PSLG segment and a convex hull segment, which can cause\n");
+  printf(
+"        overrefinement or failure if Triangle runs out of precision.  If\n");
+  printf(
+"        you are refining a mesh, the -c switch works differently; it\n");
+  printf(
+"        generates the set of boundary edges of the mesh, rather than the\n");
+  printf("        convex hull.\n");
+  printf(
+"    -e  Outputs (to an .edge file) a list of edges of the triangulation.\n");
+  printf(
+"    -v  Outputs the Voronoi diagram associated with the triangulation.\n");
+  printf("        Does not attempt to detect degeneracies.\n");
+  printf(
+"    -n  Outputs (to a .neigh file) a list of triangles neighboring each\n");
+  printf("        triangle.\n");
+  printf(
+"    -g  Outputs the mesh to an Object File Format (.off) file, suitable for\n"
+);
+  printf("        viewing with the Geometry Center's Geomview package.\n");
+  printf(
+"    -B  No boundary markers in the output .node, .poly, and .edge output\n");
+  printf(
+"        files.  See the detailed discussion of boundary markers below.\n");
+  printf(
+"    -P  No output .poly file.  Saves disk space, but you lose the ability\n");
+  printf(
+"        to impose segment constraints on later refinements of the mesh.\n");
+  printf("    -N  No output .node file.\n");
+  printf("    -E  No output .ele file.\n");
+  printf(
+"    -I  No iteration numbers.  Suppresses the output of .node and .poly\n");
+  printf(
+"        files, so your input files won't be overwritten.  (If your input is\n"
+);
+  printf(
+"        a .poly file only, a .node file will be written.)  Cannot be used\n");
+  printf(
+"        with the -r switch, because that would overwrite your input .ele\n");
+  printf(
+"        file.  Shouldn't be used with the -s, -q, or -a switch if you are\n");
+  printf(
+"        using a .node file for input, because no .node file will be\n");
+  printf("        written, so there will be no record of any added points.\n");
+  printf("    -O  No holes.  Ignores the holes in the .poly file.\n");
+  printf(
+"    -X  No exact arithmetic.  Normally, Triangle uses exact floating-point\n"
+);
+  printf(
+"        arithmetic for certain tests if it thinks the inexact tests are not\n"
+);
+  printf(
+"        accurate enough.  Exact arithmetic ensures the robustness of the\n");
+  printf(
+"        triangulation algorithms, despite floating-point roundoff error.\n");
+  printf(
+"        Disabling exact arithmetic with the -X switch will cause a small\n");
+  printf(
+"        improvement in speed and create the possibility (albeit small) that\n"
+);
+  printf(
+"        Triangle will fail to produce a valid mesh.  Not recommended.\n");
+  printf(
+"    -z  Numbers all items starting from zero (rather than one).  Note that\n"
+);
+  printf(
+"        this switch is normally overrided by the value used to number the\n");
+  printf(
+"        first point of the input .node or .poly file.  However, this switch\n"
+);
+  printf("        is useful when calling Triangle from another program.\n");
+  printf(
+"    -o2 Generates second-order subparametric elements with six nodes each.\n"
+);
+  printf(
+"    -Y  No new points on the boundary.  This switch is useful when the mesh\n"
+);
+  printf(
+"        boundary must be preserved so that it conforms to some adjacent\n");
+  printf(
+"        mesh.  Be forewarned that you will probably sacrifice some of the\n");
+  printf(
+"        quality of the mesh; Triangle will try, but the resulting mesh may\n"
+);
+  printf(
+"        contain triangles of poor aspect ratio.  Works well if all the\n");
+  printf(
+"        boundary points are closely spaced.  Specify this switch twice\n");
+  printf(
+"        (`-YY') to prevent all segment splitting, including internal\n");
+  printf("        boundaries.\n");
+  printf(
+"    -S  Specifies the maximum number of Steiner points (points that are not\n"
+);
+  printf(
+"        in the input, but are added to meet the constraints of minimum\n");
+  printf(
+"        angle and maximum area).  The default is to allow an unlimited\n");
+  printf(
+"        number.  If you specify this switch with no number after it,\n");
+  printf(
+"        the limit is set to zero.  Triangle always adds points at segment\n");
+  printf(
+"        intersections, even if it needs to use more points than the limit\n");
+  printf(
+"        you set.  When Triangle inserts segments by splitting (-s), it\n");
+  printf(
+"        always adds enough points to ensure that all the segments appear in\n"
+);
+  printf(
+"        the triangulation, again ignoring the limit.  Be forewarned that\n");
+  printf(
+"        the -S switch may result in a conforming triangulation that is not\n"
+);
+  printf(
+"        truly Delaunay, because Triangle may be forced to stop adding\n");
+  printf(
+"        points when the mesh is in a state where a segment is non-Delaunay\n"
+);
+  printf(
+"        and needs to be split.  If so, Triangle will print a warning.\n");
+  printf(
+"    -i  Uses an incremental rather than divide-and-conquer algorithm to\n");
+  printf(
+"        form a Delaunay triangulation.  Try it if the divide-and-conquer\n");
+  printf("        algorithm fails.\n");
+  printf(
+"    -F  Uses Steven Fortune's sweepline algorithm to form a Delaunay\n");
+  printf(
+"        triangulation.  Warning:  does not use exact arithmetic for all\n");
+  printf("        calculations.  An exact result is not guaranteed.\n");
+  printf(
+"    -l  Uses only vertical cuts in the divide-and-conquer algorithm.  By\n");
+  printf(
+"        default, Triangle uses alternating vertical and horizontal cuts,\n");
+  printf(
+"        which usually improve the speed except with point sets that are\n");
+  printf(
+"        small or short and wide.  This switch is primarily of theoretical\n");
+  printf("        interest.\n");
+  printf(
+"    -s  Specifies that segments should be forced into the triangulation by\n"
+);
+  printf(
+"        recursively splitting them at their midpoints, rather than by\n");
+  printf(
+"        generating a constrained Delaunay triangulation.  Segment splitting\n"
+);
+  printf(
+"        is true to Ruppert's original algorithm, but can create needlessly\n"
+);
+  printf("        small triangles near external small features.\n");
+  printf(
+"    -C  Check the consistency of the final mesh.  Uses exact arithmetic for\n"
+);
+  printf(
+"        checking, even if the -X switch is used.  Useful if you suspect\n");
+  printf("        Triangle is buggy.\n");
+  printf(
+"    -Q  Quiet: Suppresses all explanation of what Triangle is doing, unless\n"
+);
+  printf("        an error occurs.\n");
+  printf(
+"    -V  Verbose: Gives detailed information about what Triangle is doing.\n");
+  printf(
+"        Add more `V's for increasing amount of detail.  `-V' gives\n");
+  printf(
+"        information on algorithmic progress and more detailed statistics.\n");
+  printf(
+"        `-VV' gives point-by-point details, and will print so much that\n");
+  printf(
+"        Triangle will run much more slowly.  `-VVV' gives information only\n"
+);
+  printf("        a debugger could love.\n");
+  printf("    -h  Help:  Displays these instructions.\n");
+  printf("\n");
+  printf("Definitions:\n");
+  printf("\n");
+  printf(
+"  A Delaunay triangulation of a point set is a triangulation whose vertices\n"
+);
+  printf(
+"  are the point set, having the property that no point in the point set\n");
+  printf(
+"  falls in the interior of the circumcircle (circle that passes through all\n"
+);
+  printf("  three vertices) of any triangle in the triangulation.\n\n");
+  printf(
+"  A Voronoi diagram of a point set is a subdivision of the plane into\n");
+  printf(
+"  polygonal regions (some of which may be infinite), where each region is\n");
+  printf(
+"  the set of points in the plane that are closer to some input point than\n");
+  printf(
+"  to any other input point.  (The Voronoi diagram is the geometric dual of\n"
+);
+  printf("  the Delaunay triangulation.)\n\n");
+  printf(
+"  A Planar Straight Line Graph (PSLG) is a collection of points and\n");
+  printf(
+"  segments.  Segments are simply edges, whose endpoints are points in the\n");
+  printf(
+"  PSLG.  The file format for PSLGs (.poly files) is described below.\n");
+  printf("\n");
+  printf(
+"  A constrained Delaunay triangulation of a PSLG is similar to a Delaunay\n");
+  printf(
+"  triangulation, but each PSLG segment is present as a single edge in the\n");
+  printf(
+"  triangulation.  (A constrained Delaunay triangulation is not truly a\n");
+  printf("  Delaunay triangulation.)\n\n");
+  printf(
+"  A conforming Delaunay triangulation of a PSLG is a true Delaunay\n");
+  printf(
+"  triangulation in which each PSLG segment may have been subdivided into\n");
+  printf(
+"  several edges by the insertion of additional points.  These inserted\n");
+  printf(
+"  points are necessary to allow the segments to exist in the mesh while\n");
+  printf("  maintaining the Delaunay property.\n\n");
+  printf("File Formats:\n\n");
+  printf(
+"  All files may contain comments prefixed by the character '#'.  Points,\n");
+  printf(
+"  triangles, edges, holes, and maximum area constraints must be numbered\n");
+  printf(
+"  consecutively, starting from either 1 or 0.  Whichever you choose, all\n");
+  printf(
+"  input files must be consistent; if the nodes are numbered from 1, so must\n"
+);
+  printf(
+"  be all other objects.  Triangle automatically detects your choice while\n");
+  printf(
+"  reading the .node (or .poly) file.  (When calling Triangle from another\n");
+  printf(
+"  program, use the -z switch if you wish to number objects from zero.)\n");
+  printf("  Examples of these file formats are given below.\n\n");
+  printf("  .node files:\n");
+  printf(
+"    First line:  <# of points> <dimension (must be 2)> <# of attributes>\n");
+  printf(
+"                                           <# of boundary markers (0 or 1)>\n"
+);
+  printf(
+"    Remaining lines:  <point #> <x> <y> [attributes] [boundary marker]\n");
+  printf("\n");
+  printf(
+"    The attributes, which are typically floating-point values of physical\n");
+  printf(
+"    quantities (such as mass or conductivity) associated with the nodes of\n"
+);
+  printf(
+"    a finite element mesh, are copied unchanged to the output mesh.  If -s,\n"
+);
+  printf(
+"    -q, or -a is selected, each new Steiner point added to the mesh will\n");
+  printf("    have attributes assigned to it by linear interpolation.\n\n");
+  printf(
+"    If the fourth entry of the first line is `1', the last column of the\n");
+  printf(
+"    remainder of the file is assumed to contain boundary markers.  Boundary\n"
+);
+  printf(
+"    markers are used to identify boundary points and points resting on PSLG\n"
+);
+  printf(
+"    segments; a complete description appears in a section below.  The .node\n"
+);
+  printf(
+"    file produced by Triangle will contain boundary markers in the last\n");
+  printf("    column unless they are suppressed by the -B switch.\n\n");
+  printf("  .ele files:\n");
+  printf(
+"    First line:  <# of triangles> <points per triangle> <# of attributes>\n");
+  printf(
+"    Remaining lines:  <triangle #> <point> <point> <point> ... [attributes]\n"
+);
+  printf("\n");
+  printf(
+"    Points are indices into the corresponding .node file.  The first three\n"
+);
+  printf(
+"    points are the corners, and are listed in counterclockwise order around\n"
+);
+  printf(
+"    each triangle.  (The remaining points, if any, depend on the type of\n");
+  printf(
+"    finite element used.)  The attributes are just like those of .node\n");
+  printf(
+"    files.  Because there is no simple mapping from input to output\n");
+  printf(
+"    triangles, an attempt is made to interpolate attributes, which may\n");
+  printf(
+"    result in a good deal of diffusion of attributes among nearby triangles\n"
+);
+  printf(
+"    as the triangulation is refined.  Diffusion does not occur across\n");
+  printf(
+"    segments, so attributes used to identify segment-bounded regions remain\n"
+);
+  printf(
+"    intact.  In output .ele files, all triangles have three points each\n");
+  printf(
+"    unless the -o2 switch is used, in which case they have six, and the\n");
+  printf(
+"    fourth, fifth, and sixth points lie on the midpoints of the edges\n");
+  printf("    opposite the first, second, and third corners.\n\n");
+  printf("  .poly files:\n");
+  printf(
+"    First line:  <# of points> <dimension (must be 2)> <# of attributes>\n");
+  printf(
+"                                           <# of boundary markers (0 or 1)>\n"
+);
+  printf(
+"    Following lines:  <point #> <x> <y> [attributes] [boundary marker]\n");
+  printf("    One line:  <# of segments> <# of boundary markers (0 or 1)>\n");
+  printf(
+"    Following lines:  <segment #> <endpoint> <endpoint> [boundary marker]\n");
+  printf("    One line:  <# of holes>\n");
+  printf("    Following lines:  <hole #> <x> <y>\n");
+  printf(
+"    Optional line:  <# of regional attributes and/or area constraints>\n");
+  printf(
+"    Optional following lines:  <constraint #> <x> <y> <attrib> <max area>\n");
+  printf("\n");
+  printf(
+"    A .poly file represents a PSLG, as well as some additional information.\n"
+);
+  printf(
+"    The first section lists all the points, and is identical to the format\n"
+);
+  printf(
+"    of .node files.  <# of points> may be set to zero to indicate that the\n"
+);
+  printf(
+"    points are listed in a separate .node file; .poly files produced by\n");
+  printf(
+"    Triangle always have this format.  This has the advantage that a point\n"
+);
+  printf(
+"    set may easily be triangulated with or without segments.  (The same\n");
+  printf(
+"    effect can be achieved, albeit using more disk space, by making a copy\n"
+);
+  printf(
+"    of the .poly file with the extension .node; all sections of the file\n");
+  printf("    but the first are ignored.)\n\n");
+  printf(
+"    The second section lists the segments.  Segments are edges whose\n");
+  printf(
+"    presence in the triangulation is enforced.  Each segment is specified\n");
+  printf(
+"    by listing the indices of its two endpoints.  This means that you must\n"
+);
+  printf(
+"    include its endpoints in the point list.  If -s, -q, and -a are not\n");
+  printf(
+"    selected, Triangle will produce a constrained Delaunay triangulation,\n");
+  printf(
+"    in which each segment appears as a single edge in the triangulation.\n");
+  printf(
+"    If -q or -a is selected, Triangle will produce a conforming Delaunay\n");
+  printf(
+"    triangulation, in which segments may be subdivided into smaller edges.\n"
+);
+  printf("    Each segment, like each point, may have a boundary marker.\n\n");
+  printf(
+"    The third section lists holes (and concavities, if -c is selected) in\n");
+  printf(
+"    the triangulation.  Holes are specified by identifying a point inside\n");
+  printf(
+"    each hole.  After the triangulation is formed, Triangle creates holes\n");
+  printf(
+"    by eating triangles, spreading out from each hole point until its\n");
+  printf(
+"    progress is blocked by PSLG segments; you must be careful to enclose\n");
+  printf(
+"    each hole in segments, or your whole triangulation may be eaten away.\n");
+  printf(
+"    If the two triangles abutting a segment are eaten, the segment itself\n");
+  printf(
+"    is also eaten.  Do not place a hole directly on a segment; if you do,\n");
+  printf("    Triangle will choose one side of the segment arbitrarily.\n\n");
+  printf(
+"    The optional fourth section lists regional attributes (to be assigned\n");
+  printf(
+"    to all triangles in a region) and regional constraints on the maximum\n");
+  printf(
+"    triangle area.  Triangle will read this section only if the -A switch\n");
+  printf(
+"    is used or the -a switch is used without a number following it, and the\n"
+);
+  printf(
+"    -r switch is not used.  Regional attributes and area constraints are\n");
+  printf(
+"    propagated in the same manner as holes; you specify a point for each\n");
+  printf(
+"    attribute and/or constraint, and the attribute and/or constraint will\n");
+  printf(
+"    affect the whole region (bounded by segments) containing the point.  If\n"
+);
+  printf(
+"    two values are written on a line after the x and y coordinate, the\n");
+  printf(
+"    former is assumed to be a regional attribute (but will only be applied\n"
+);
+  printf(
+"    if the -A switch is selected), and the latter is assumed to be a\n");
+  printf(
+"    regional area constraint (but will only be applied if the -a switch is\n"
+);
+  printf(
+"    selected).  You may also specify just one value after the coordinates,\n"
+);
+  printf(
+"    which can serve as both an attribute and an area constraint, depending\n"
+);
+  printf(
+"    on the choice of switches.  If you are using the -A and -a switches\n");
+  printf(
+"    simultaneously and wish to assign an attribute to some region without\n");
+  printf("    imposing an area constraint, use a negative maximum area.\n\n");
+  printf(
+"    When a triangulation is created from a .poly file, you must either\n");
+  printf(
+"    enclose the entire region to be triangulated in PSLG segments, or\n");
+  printf(
+"    use the -c switch, which encloses the convex hull of the input point\n");
+  printf(
+"    set.  If you do not use the -c switch, Triangle will eat all triangles\n"
+);
+  printf(
+"    on the outer boundary that are not protected by segments; if you are\n");
+  printf(
+"    not careful, your whole triangulation may be eaten away.  If you do\n");
+  printf(
+"    use the -c switch, you can still produce concavities by appropriate\n");
+  printf("    placement of holes just inside the convex hull.\n\n");
+  printf(
+"    An ideal PSLG has no intersecting segments, nor any points that lie\n");
+  printf(
+"    upon segments (except, of course, the endpoints of each segment.)  You\n"
+);
+  printf(
+"    aren't required to make your .poly files ideal, but you should be aware\n"
+);
+  printf(
+"    of what can go wrong.  Segment intersections are relatively safe -\n");
+  printf(
+"    Triangle will calculate the intersection points for you and add them to\n"
+);
+  printf(
+"    the triangulation - as long as your machine's floating-point precision\n"
+);
+  printf(
+"    doesn't become a problem.  You are tempting the fates if you have three\n"
+);
+  printf(
+"    segments that cross at the same location, and expect Triangle to figure\n"
+);
+  printf(
+"    out where the intersection point is.  Thanks to floating-point roundoff\n"
+);
+  printf(
+"    error, Triangle will probably decide that the three segments intersect\n"
+);
+  printf(
+"    at three different points, and you will find a minuscule triangle in\n");
+  printf(
+"    your output - unless Triangle tries to refine the tiny triangle, uses\n");
+  printf(
+"    up the last bit of machine precision, and fails to terminate at all.\n");
+  printf(
+"    You're better off putting the intersection point in the input files,\n");
+  printf(
+"    and manually breaking up each segment into two.  Similarly, if you\n");
+  printf(
+"    place a point at the middle of a segment, and hope that Triangle will\n");
+  printf(
+"    break up the segment at that point, you might get lucky.  On the other\n"
+);
+  printf(
+"    hand, Triangle might decide that the point doesn't lie precisely on the\n"
+);
+  printf(
+"    line, and you'll have a needle-sharp triangle in your output - or a lot\n"
+);
+  printf("    of tiny triangles if you're generating a quality mesh.\n\n");
+  printf(
+"    When Triangle reads a .poly file, it also writes a .poly file, which\n");
+  printf(
+"    includes all edges that are part of input segments.  If the -c switch\n");
+  printf(
+"    is used, the output .poly file will also include all of the edges on\n");
+  printf(
+"    the convex hull.  Hence, the output .poly file is useful for finding\n");
+  printf(
+"    edges associated with input segments and setting boundary conditions in\n"
+);
+  printf(
+"    finite element simulations.  More importantly, you will need it if you\n"
+);
+  printf(
+"    plan to refine the output mesh, and don't want segments to be missing\n");
+  printf("    in later triangulations.\n\n");
+  printf("  .area files:\n");
+  printf("    First line:  <# of triangles>\n");
+  printf("    Following lines:  <triangle #> <maximum area>\n\n");
+  printf(
+"    An .area file associates with each triangle a maximum area that is used\n"
+);
+  printf(
+"    for mesh refinement.  As with other file formats, every triangle must\n");
+  printf(
+"    be represented, and they must be numbered consecutively.  A triangle\n");
+  printf(
+"    may be left unconstrained by assigning it a negative maximum area.\n");
+  printf("\n");
+  printf("  .edge files:\n");
+  printf("    First line:  <# of edges> <# of boundary markers (0 or 1)>\n");
+  printf(
+"    Following lines:  <edge #> <endpoint> <endpoint> [boundary marker]\n");
+  printf("\n");
+  printf(
+"    Endpoints are indices into the corresponding .node file.  Triangle can\n"
+);
+  printf(
+"    produce .edge files (use the -e switch), but cannot read them.  The\n");
+  printf(
+"    optional column of boundary markers is suppressed by the -B switch.\n");
+  printf("\n");
+  printf(
+"    In Voronoi diagrams, one also finds a special kind of edge that is an\n");
+  printf(
+"    infinite ray with only one endpoint.  For these edges, a different\n");
+  printf("    format is used:\n\n");
+  printf("        <edge #> <endpoint> -1 <direction x> <direction y>\n\n");
+  printf(
+"    The `direction' is a floating-point vector that indicates the direction\n"
+);
+  printf("    of the infinite ray.\n\n");
+  printf("  .neigh files:\n");
+  printf(
+"    First line:  <# of triangles> <# of neighbors per triangle (always 3)>\n"
+);
+  printf(
+"    Following lines:  <triangle #> <neighbor> <neighbor> <neighbor>\n");
+  printf("\n");
+  printf(
+"    Neighbors are indices into the corresponding .ele file.  An index of -1\n"
+);
+  printf(
+"    indicates a mesh boundary, and therefore no neighbor.  Triangle can\n");
+  printf(
+"    produce .neigh files (use the -n switch), but cannot read them.\n");
+  printf("\n");
+  printf(
+"    The first neighbor of triangle i is opposite the first corner of\n");
+  printf("    triangle i, and so on.\n\n");
+  printf("Boundary Markers:\n\n");
+  printf(
+"  Boundary markers are tags used mainly to identify which output points and\n"
+);
+  printf(
+"  edges are associated with which PSLG segment, and to identify which\n");
+  printf(
+"  points and edges occur on a boundary of the triangulation.  A common use\n"
+);
+  printf(
+"  is to determine where boundary conditions should be applied to a finite\n");
+  printf(
+"  element mesh.  You can prevent boundary markers from being written into\n");
+  printf("  files produced by Triangle by using the -B switch.\n\n");
+  printf(
+"  The boundary marker associated with each segment in an output .poly file\n"
+);
+  printf("  or edge in an output .edge file is chosen as follows:\n");
+  printf(
+"    - If an output edge is part or all of a PSLG segment with a nonzero\n");
+  printf(
+"      boundary marker, then the edge is assigned the same marker.\n");
+  printf(
+"    - Otherwise, if the edge occurs on a boundary of the triangulation\n");
+  printf(
+"      (including boundaries of holes), then the edge is assigned the marker\n"
+);
+  printf("      one (1).\n");
+  printf("    - Otherwise, the edge is assigned the marker zero (0).\n");
+  printf(
+"  The boundary marker associated with each point in an output .node file is\n"
+);
+  printf("  chosen as follows:\n");
+  printf(
+"    - If a point is assigned a nonzero boundary marker in the input file,\n");
+  printf(
+"      then it is assigned the same marker in the output .node file.\n");
+  printf(
+"    - Otherwise, if the point lies on a PSLG segment (including the\n");
+  printf(
+"      segment's endpoints) with a nonzero boundary marker, then the point\n");
+  printf(
+"      is assigned the same marker.  If the point lies on several such\n");
+  printf("      segments, one of the markers is chosen arbitrarily.\n");
+  printf(
+"    - Otherwise, if the point occurs on a boundary of the triangulation,\n");
+  printf("      then the point is assigned the marker one (1).\n");
+  printf("    - Otherwise, the point is assigned the marker zero (0).\n");
+  printf("\n");
+  printf(
+"  If you want Triangle to determine for you which points and edges are on\n");
+  printf(
+"  the boundary, assign them the boundary marker zero (or use no markers at\n"
+);
+  printf(
+"  all) in your input files.  Alternatively, you can mark some of them and\n");
+  printf("  leave others marked zero, allowing Triangle to label them.\n\n");
+  printf("Triangulation Iteration Numbers:\n\n");
+  printf(
+"  Because Triangle can read and refine its own triangulations, input\n");
+  printf(
+"  and output files have iteration numbers.  For instance, Triangle might\n");
+  printf(
+"  read the files mesh.3.node, mesh.3.ele, and mesh.3.poly, refine the\n");
+  printf(
+"  triangulation, and output the files mesh.4.node, mesh.4.ele, and\n");
+  printf("  mesh.4.poly.  Files with no iteration number are treated as if\n");
+  printf(
+"  their iteration number is zero; hence, Triangle might read the file\n");
+  printf(
+"  points.node, triangulate it, and produce the files points.1.node and\n");
+  printf("  points.1.ele.\n\n");
+  printf(
+"  Iteration numbers allow you to create a sequence of successively finer\n");
+  printf(
+"  meshes suitable for multigrid methods.  They also allow you to produce a\n"
+);
+  printf(
+"  sequence of meshes using error estimate-driven mesh refinement.\n");
+  printf("\n");
+  printf(
+"  If you're not using refinement or quality meshing, and you don't like\n");
+  printf(
+"  iteration numbers, use the -I switch to disable them.  This switch will\n");
+  printf(
+"  also disable output of .node and .poly files to prevent your input files\n"
+);
+  printf(
+"  from being overwritten.  (If the input is a .poly file that contains its\n"
+);
+  printf("  own points, a .node file will be written.)\n\n");
+  printf("Examples of How to Use Triangle:\n\n");
+  printf(
+"  `triangle dots' will read points from dots.node, and write their Delaunay\n"
+);
+  printf(
+"  triangulation to dots.1.node and dots.1.ele.  (dots.1.node will be\n");
+  printf(
+"  identical to dots.node.)  `triangle -I dots' writes the triangulation to\n"
+);
+  printf(
+"  dots.ele instead.  (No additional .node file is needed, so none is\n");
+  printf("  written.)\n\n");
+  printf(
+"  `triangle -pe object.1' will read a PSLG from object.1.poly (and possibly\n"
+);
+  printf(
+"  object.1.node, if the points are omitted from object.1.poly) and write\n");
+  printf("  their constrained Delaunay triangulation to object.2.node and\n");
+  printf(
+"  object.2.ele.  The segments will be copied to object.2.poly, and all\n");
+  printf("  edges will be written to object.2.edge.\n\n");
+  printf(
+"  `triangle -pq31.5a.1 object' will read a PSLG from object.poly (and\n");
+  printf(
+"  possibly object.node), generate a mesh whose angles are all greater than\n"
+);
+  printf(
+"  31.5 degrees and whose triangles all have area smaller than 0.1, and\n");
+  printf(
+"  write the mesh to object.1.node and object.1.ele.  Each segment may have\n"
+);
+  printf(
+"  been broken up into multiple edges; the resulting constrained edges are\n");
+  printf("  written to object.1.poly.\n\n");
+  printf(
+"  Here is a sample file `box.poly' describing a square with a square hole:\n"
+);
+  printf("\n");
+  printf(
+"    # A box with eight points in 2D, no attributes, one boundary marker.\n");
+  printf("    8 2 0 1\n");
+  printf("    # Outer box has these vertices:\n");
+  printf("     1   0 0   0\n");
+  printf("     2   0 3   0\n");
+  printf("     3   3 0   0\n");
+  printf("     4   3 3   33     # A special marker for this point.\n");
+  printf("    # Inner square has these vertices:\n");
+  printf("     5   1 1   0\n");
+  printf("     6   1 2   0\n");
+  printf("     7   2 1   0\n");
+  printf("     8   2 2   0\n");
+  printf("    # Five segments with boundary markers.\n");
+  printf("    5 1\n");
+  printf("     1   1 2   5      # Left side of outer box.\n");
+  printf("     2   5 7   0      # Segments 2 through 5 enclose the hole.\n");
+  printf("     3   7 8   0\n");
+  printf("     4   8 6   10\n");
+  printf("     5   6 5   0\n");
+  printf("    # One hole in the middle of the inner square.\n");
+  printf("    1\n");
+  printf("     1   1.5 1.5\n\n");
+  printf(
+"  Note that some segments are missing from the outer square, so one must\n");
+  printf(
+"  use the `-c' switch.  After `triangle -pqc box.poly', here is the output\n"
+);
+  printf(
+"  file `box.1.node', with twelve points.  The last four points were added\n");
+  printf(
+"  to meet the angle constraint.  Points 1, 2, and 9 have markers from\n");
+  printf(
+"  segment 1.  Points 6 and 8 have markers from segment 4.  All the other\n");
+  printf(
+"  points but 4 have been marked to indicate that they lie on a boundary.\n");
+  printf("\n");
+  printf("    12  2  0  1\n");
+  printf("       1    0   0      5\n");
+  printf("       2    0   3      5\n");
+  printf("       3    3   0      1\n");
+  printf("       4    3   3     33\n");
+  printf("       5    1   1      1\n");
+  printf("       6    1   2     10\n");
+  printf("       7    2   1      1\n");
+  printf("       8    2   2     10\n");
+  printf("       9    0   1.5    5\n");
+  printf("      10    1.5   0    1\n");
+  printf("      11    3   1.5    1\n");
+  printf("      12    1.5   3    1\n");
+  printf("    # Generated by triangle -pqc box.poly\n\n");
+  printf("  Here is the output file `box.1.ele', with twelve triangles.\n\n");
+  printf("    12  3  0\n");
+  printf("       1     5   6   9\n");
+  printf("       2    10   3   7\n");
+  printf("       3     6   8  12\n");
+  printf("       4     9   1   5\n");
+  printf("       5     6   2   9\n");
+  printf("       6     7   3  11\n");
+  printf("       7    11   4   8\n");
+  printf("       8     7   5  10\n");
+  printf("       9    12   2   6\n");
+  printf("      10     8   7  11\n");
+  printf("      11     5   1  10\n");
+  printf("      12     8   4  12\n");
+  printf("    # Generated by triangle -pqc box.poly\n\n");
+  printf(
+"  Here is the output file `box.1.poly'.  Note that segments have been added\n"
+);
+  printf(
+"  to represent the convex hull, and some segments have been split by newly\n"
+);
+  printf(
+"  added points.  Note also that <# of points> is set to zero to indicate\n");
+  printf("  that the points should be read from the .node file.\n\n");
+  printf("    0  2  0  1\n");
+  printf("    12  1\n");
+  printf("       1     1   9     5\n");
+  printf("       2     5   7     1\n");
+  printf("       3     8   7     1\n");
+  printf("       4     6   8    10\n");
+  printf("       5     5   6     1\n");
+  printf("       6     3  10     1\n");
+  printf("       7     4  11     1\n");
+  printf("       8     2  12     1\n");
+  printf("       9     9   2     5\n");
+  printf("      10    10   1     1\n");
+  printf("      11    11   3     1\n");
+  printf("      12    12   4     1\n");
+  printf("    1\n");
+  printf("       1   1.5 1.5\n");
+  printf("    # Generated by triangle -pqc box.poly\n\n");
+  printf("Refinement and Area Constraints:\n\n");
+  printf(
+"  The -r switch causes a mesh (.node and .ele files) to be read and\n");
+  printf(
+"  refined.  If the -p switch is also used, a .poly file is read and used to\n"
+);
+  printf(
+"  specify edges that are constrained and cannot be eliminated (although\n");
+  printf(
+"  they can be divided into smaller edges) by the refinement process.\n");
+  printf("\n");
+  printf(
+"  When you refine a mesh, you generally want to impose tighter quality\n");
+  printf(
+"  constraints.  One way to accomplish this is to use -q with a larger\n");
+  printf(
+"  angle, or -a followed by a smaller area than you used to generate the\n");
+  printf(
+"  mesh you are refining.  Another way to do this is to create an .area\n");
+  printf(
+"  file, which specifies a maximum area for each triangle, and use the -a\n");
+  printf(
+"  switch (without a number following).  Each triangle's area constraint is\n"
+);
+  printf(
+"  applied to that triangle.  Area constraints tend to diffuse as the mesh\n");
+  printf(
+"  is refined, so if there are large variations in area constraint between\n");
+  printf("  adjacent triangles, you may not get the results you want.\n\n");
+  printf(
+"  If you are refining a mesh composed of linear (three-node) elements, the\n"
+);
+  printf(
+"  output mesh will contain all the nodes present in the input mesh, in the\n"
+);
+  printf(
+"  same order, with new nodes added at the end of the .node file.  However,\n"
+);
+  printf(
+"  there is no guarantee that each output element is contained in a single\n");
+  printf(
+"  input element.  Often, output elements will overlap two input elements,\n");
+  printf(
+"  and input edges are not present in the output mesh.  Hence, a sequence of\n"
+);
+  printf(
+"  refined meshes will form a hierarchy of nodes, but not a hierarchy of\n");
+  printf(
+"  elements.  If you a refining a mesh of higher-order elements, the\n");
+  printf(
+"  hierarchical property applies only to the nodes at the corners of an\n");
+  printf("  element; other nodes may not be present in the refined mesh.\n\n");
+  printf(
+"  It is important to understand that maximum area constraints in .poly\n");
+  printf(
+"  files are handled differently from those in .area files.  A maximum area\n"
+);
+  printf(
+"  in a .poly file applies to the whole (segment-bounded) region in which a\n"
+);
+  printf(
+"  point falls, whereas a maximum area in an .area file applies to only one\n"
+);
+  printf(
+"  triangle.  Area constraints in .poly files are used only when a mesh is\n");
+  printf(
+"  first generated, whereas area constraints in .area files are used only to\n"
+);
+  printf(
+"  refine an existing mesh, and are typically based on a posteriori error\n");
+  printf(
+"  estimates resulting from a finite element simulation on that mesh.\n");
+  printf("\n");
+  printf(
+"  `triangle -rq25 object.1' will read object.1.node and object.1.ele, then\n"
+);
+  printf(
+"  refine the triangulation to enforce a 25 degree minimum angle, and then\n");
+  printf(
+"  write the refined triangulation to object.2.node and object.2.ele.\n");
+  printf("\n");
+  printf(
+"  `triangle -rpaa6.2 z.3' will read z.3.node, z.3.ele, z.3.poly, and\n");
+  printf(
+"  z.3.area.  After reconstructing the mesh and its segments, Triangle will\n"
+);
+  printf(
+"  refine the mesh so that no triangle has area greater than 6.2, and\n");
+  printf(
+"  furthermore the triangles satisfy the maximum area constraints in\n");
+  printf(
+"  z.3.area.  The output is written to z.4.node, z.4.ele, and z.4.poly.\n");
+  printf("\n");
+  printf(
+"  The sequence `triangle -qa1 x', `triangle -rqa.3 x.1', `triangle -rqa.1\n");
+  printf(
+"  x.2' creates a sequence of successively finer meshes x.1, x.2, and x.3,\n");
+  printf("  suitable for multigrid.\n\n");
+  printf("Convex Hulls and Mesh Boundaries:\n\n");
+  printf(
+"  If the input is a point set (rather than a PSLG), Triangle produces its\n");
+  printf(
+"  convex hull as a by-product in the output .poly file if you use the -c\n");
+  printf(
+"  switch.  There are faster algorithms for finding a two-dimensional convex\n"
+);
+  printf(
+"  hull than triangulation, of course, but this one comes for free.  If the\n"
+);
+  printf(
+"  input is an unconstrained mesh (you are using the -r switch but not the\n");
+  printf(
+"  -p switch), Triangle produces a list of its boundary edges (including\n");
+  printf("  hole boundaries) as a by-product if you use the -c switch.\n\n");
+  printf("Voronoi Diagrams:\n\n");
+  printf(
+"  The -v switch produces a Voronoi diagram, in files suffixed .v.node and\n");
+  printf(
+"  .v.edge.  For example, `triangle -v points' will read points.node,\n");
+  printf(
+"  produce its Delaunay triangulation in points.1.node and points.1.ele,\n");
+  printf(
+"  and produce its Voronoi diagram in points.1.v.node and points.1.v.edge.\n");
+  printf(
+"  The .v.node file contains a list of all Voronoi vertices, and the .v.edge\n"
+);
+  printf(
+"  file contains a list of all Voronoi edges, some of which may be infinite\n"
+);
+  printf(
+"  rays.  (The choice of filenames makes it easy to run the set of Voronoi\n");
+  printf("  vertices through Triangle, if so desired.)\n\n");
+  printf(
+"  This implementation does not use exact arithmetic to compute the Voronoi\n"
+);
+  printf(
+"  vertices, and does not check whether neighboring vertices are identical.\n"
+);
+  printf(
+"  Be forewarned that if the Delaunay triangulation is degenerate or\n");
+  printf(
+"  near-degenerate, the Voronoi diagram may have duplicate points, crossing\n"
+);
+  printf(
+"  edges, or infinite rays whose direction vector is zero.  Also, if you\n");
+  printf(
+"  generate a constrained (as opposed to conforming) Delaunay triangulation,\n"
+);
+  printf(
+"  or if the triangulation has holes, the corresponding Voronoi diagram is\n");
+  printf("  likely to have crossing edges and unlikely to make sense.\n\n");
+  printf("Mesh Topology:\n\n");
+  printf(
+"  You may wish to know which triangles are adjacent to a certain Delaunay\n");
+  printf(
+"  edge in an .edge file, which Voronoi regions are adjacent to a certain\n");
+  printf(
+"  Voronoi edge in a .v.edge file, or which Voronoi regions are adjacent to\n"
+);
+  printf(
+"  each other.  All of this information can be found by cross-referencing\n");
+  printf(
+"  output files with the recollection that the Delaunay triangulation and\n");
+  printf("  the Voronoi diagrams are planar duals.\n\n");
+  printf(
+"  Specifically, edge i of an .edge file is the dual of Voronoi edge i of\n");
+  printf(
+"  the corresponding .v.edge file, and is rotated 90 degrees counterclock-\n");
+  printf(
+"  wise from the Voronoi edge.  Triangle j of an .ele file is the dual of\n");
+  printf(
+"  vertex j of the corresponding .v.node file; and Voronoi region k is the\n");
+  printf("  dual of point k of the corresponding .node file.\n\n");
+  printf(
+"  Hence, to find the triangles adjacent to a Delaunay edge, look at the\n");
+  printf(
+"  vertices of the corresponding Voronoi edge; their dual triangles are on\n");
+  printf(
+"  the left and right of the Delaunay edge, respectively.  To find the\n");
+  printf(
+"  Voronoi regions adjacent to a Voronoi edge, look at the endpoints of the\n"
+);
+  printf(
+"  corresponding Delaunay edge; their dual regions are on the right and left\n"
+);
+  printf(
+"  of the Voronoi edge, respectively.  To find which Voronoi regions are\n");
+  printf("  adjacent to each other, just read the list of Delaunay edges.\n");
+  printf("\n");
+  printf("Statistics:\n");
+  printf("\n");
+  printf(
+"  After generating a mesh, Triangle prints a count of the number of points,\n"
+);
+  printf(
+"  triangles, edges, boundary edges, and segments in the output mesh.  If\n");
+  printf(
+"  you've forgotten the statistics for an existing mesh, the -rNEP switches\n"
+);
+  printf(
+"  (or -rpNEP if you've got a .poly file for the existing mesh) will\n");
+  printf("  regenerate these statistics without writing any output.\n\n");
+  printf(
+"  The -V switch produces extended statistics, including a rough estimate\n");
+  printf(
+"  of memory use and a histogram of triangle aspect ratios and angles in the\n"
+);
+  printf("  mesh.\n\n");
+  printf("Exact Arithmetic:\n\n");
+  printf(
+"  Triangle uses adaptive exact arithmetic to perform what computational\n");
+  printf(
+"  geometers call the `orientation' and `incircle' tests.  If the floating-\n"
+);
+  printf(
+"  point arithmetic of your machine conforms to the IEEE 754 standard (as\n");
+  printf(
+"  most workstations do), and does not use extended precision internal\n");
+  printf(
+"  registers, then your output is guaranteed to be an absolutely true\n");
+  printf("  Delaunay or conforming Delaunay triangulation, roundoff error\n");
+  printf(
+"  notwithstanding.  The word `adaptive' implies that these arithmetic\n");
+  printf(
+"  routines compute the result only to the precision necessary to guarantee\n"
+);
+  printf(
+"  correctness, so they are usually nearly as fast as their approximate\n");
+  printf(
+"  counterparts.  The exact tests can be disabled with the -X switch.  On\n");
+  printf(
+"  most inputs, this switch will reduce the computation time by about eight\n"
+);
+  printf(
+"  percent - it's not worth the risk.  There are rare difficult inputs\n");
+  printf(
+"  (having many collinear and cocircular points), however, for which the\n");
+  printf(
+"  difference could be a factor of two.  These are precisely the inputs most\n"
+);
+  printf("  likely to cause errors if you use the -X switch.\n\n");
+  printf(
+"  Unfortunately, these routines don't solve every numerical problem.  Exact\n"
+);
+  printf(
+"  arithmetic is not used to compute the positions of points, because the\n");
+  printf(
+"  bit complexity of point coordinates would grow without bound.  Hence,\n");
+  printf(
+"  segment intersections aren't computed exactly; in very unusual cases,\n");
+  printf(
+"  roundoff error in computing an intersection point might actually lead to\n"
+);
+  printf(
+"  an inverted triangle and an invalid triangulation.  (This is one reason\n");
+  printf(
+"  to compute your own intersection points in your .poly files.)  Similarly,\n"
+);
+  printf(
+"  exact arithmetic is not used to compute the vertices of the Voronoi\n");
+  printf("  diagram.\n\n");
+  printf(
+"  Underflow and overflow can also cause difficulties; the exact arithmetic\n"
+);
+  printf(
+"  routines do not ameliorate out-of-bounds exponents, which can arise\n");
+  printf(
+"  during the orientation and incircle tests.  As a rule of thumb, you\n");
+  printf(
+"  should ensure that your input values are within a range such that their\n");
+  printf(
+"  third powers can be taken without underflow or overflow.  Underflow can\n");
+  printf(
+"  silently prevent the tests from being performed exactly, while overflow\n");
+  printf("  will typically cause a floating exception.\n\n");
+  printf("Calling Triangle from Another Program:\n\n");
+  printf("  Read the file triangle.h for details.\n\n");
+  printf("Troubleshooting:\n\n");
+  printf("  Please read this section before mailing me bugs.\n\n");
+  printf("  `My output mesh has no triangles!'\n\n");
+  printf(
+"    If you're using a PSLG, you've probably failed to specify a proper set\n"
+);
+  printf(
+"    of bounding segments, or forgotten to use the -c switch.  Or you may\n");
+  printf(
+"    have placed a hole badly.  To test these possibilities, try again with\n"
+);
+  printf(
+"    the -c and -O switches.  Alternatively, all your input points may be\n");
+  printf(
+"    collinear, in which case you can hardly expect to triangulate them.\n");
+  printf("\n");
+  printf("  `Triangle doesn't terminate, or just crashes.'\n");
+  printf("\n");
+  printf(
+"    Bad things can happen when triangles get so small that the distance\n");
+  printf(
+"    between their vertices isn't much larger than the precision of your\n");
+  printf(
+"    machine's arithmetic.  If you've compiled Triangle for single-precision\n"
+);
+  printf(
+"    arithmetic, you might do better by recompiling it for double-precision.\n"
+);
+  printf(
+"    Then again, you might just have to settle for more lenient constraints\n"
+);
+  printf(
+"    on the minimum angle and the maximum area than you had planned.\n");
+  printf("\n");
+  printf(
+"    You can minimize precision problems by ensuring that the origin lies\n");
+  printf(
+"    inside your point set, or even inside the densest part of your\n");
+  printf(
+"    mesh.  On the other hand, if you're triangulating an object whose x\n");
+  printf(
+"    coordinates all fall between 6247133 and 6247134, you're not leaving\n");
+  printf("    much floating-point precision for Triangle to work with.\n\n");
+  printf(
+"    Precision problems can occur covertly if the input PSLG contains two\n");
+  printf(
+"    segments that meet (or intersect) at a very small angle, or if such an\n"
+);
+  printf(
+"    angle is introduced by the -c switch, which may occur if a point lies\n");
+  printf(
+"    ever-so-slightly inside the convex hull, and is connected by a PSLG\n");
+  printf(
+"    segment to a point on the convex hull.  If you don't realize that a\n");
+  printf(
+"    small angle is being formed, you might never discover why Triangle is\n");
+  printf(
+"    crashing.  To check for this possibility, use the -S switch (with an\n");
+  printf(
+"    appropriate limit on the number of Steiner points, found by trial-and-\n"
+);
+  printf(
+"    error) to stop Triangle early, and view the output .poly file with\n");
+  printf(
+"    Show Me (described below).  Look carefully for small angles between\n");
+  printf(
+"    segments; zoom in closely, as such segments might look like a single\n");
+  printf("    segment from a distance.\n\n");
+  printf(
+"    If some of the input values are too large, Triangle may suffer a\n");
+  printf(
+"    floating exception due to overflow when attempting to perform an\n");
+  printf(
+"    orientation or incircle test.  (Read the section on exact arithmetic\n");
+  printf(
+"    above.)  Again, I recommend compiling Triangle for double (rather\n");
+  printf("    than single) precision arithmetic.\n\n");
+  printf(
+"  `The numbering of the output points doesn't match the input points.'\n");
+  printf("\n");
+  printf(
+"    You may have eaten some of your input points with a hole, or by placing\n"
+);
+  printf("    them outside the area enclosed by segments.\n\n");
+  printf(
+"  `Triangle executes without incident, but when I look at the resulting\n");
+  printf(
+"  mesh, it has overlapping triangles or other geometric inconsistencies.'\n");
+  printf("\n");
+  printf(
+"    If you select the -X switch, Triangle's divide-and-conquer Delaunay\n");
+  printf(
+"    triangulation algorithm occasionally makes mistakes due to floating-\n");
+  printf(
+"    point roundoff error.  Although these errors are rare, don't use the -X\n"
+);
+  printf("    switch.  If you still have problems, please report the bug.\n");
+  printf("\n");
+  printf(
+"  Strange things can happen if you've taken liberties with your PSLG.  Do\n");
+  printf(
+"  you have a point lying in the middle of a segment?  Triangle sometimes\n");
+  printf(
+"  copes poorly with that sort of thing.  Do you want to lay out a collinear\n"
+);
+  printf(
+"  row of evenly spaced, segment-connected points?  Have you simply defined\n"
+);
+  printf(
+"  one long segment connecting the leftmost point to the rightmost point,\n");
+  printf(
+"  and a bunch of points lying along it?  This method occasionally works,\n");
+  printf(
+"  especially with horizontal and vertical lines, but often it doesn't, and\n"
+);
+  printf(
+"  you'll have to connect each adjacent pair of points with a separate\n");
+  printf("  segment.  If you don't like it, tough.\n\n");
+  printf(
+"  Furthermore, if you have segments that intersect other than at their\n");
+  printf(
+"  endpoints, try not to let the intersections fall extremely close to PSLG\n"
+);
+  printf("  points or each other.\n\n");
+  printf(
+"  If you have problems refining a triangulation not produced by Triangle:\n");
+  printf(
+"  Are you sure the triangulation is geometrically valid?  Is it formatted\n");
+  printf(
+"  correctly for Triangle?  Are the triangles all listed so the first three\n"
+);
+  printf("  points are their corners in counterclockwise order?\n\n");
+  printf("Show Me:\n\n");
+  printf(
+"  Triangle comes with a separate program named `Show Me', whose primary\n");
+  printf(
+"  purpose is to draw meshes on your screen or in PostScript.  Its secondary\n"
+);
+  printf(
+"  purpose is to check the validity of your input files, and do so more\n");
+  printf(
+"  thoroughly than Triangle does.  Show Me requires that you have the X\n");
+  printf(
+"  Windows system.  If you didn't receive Show Me with Triangle, complain to\n"
+);
+  printf("  whomever you obtained Triangle from, then send me mail.\n\n");
+  printf("Triangle on the Web:\n\n");
+  printf(
+"  To see an illustrated, updated version of these instructions, check out\n");
+  printf("\n");
+  printf("    http://www.cs.cmu.edu/~quake/triangle.html\n");
+  printf("\n");
+  printf("A Brief Plea:\n");
+  printf("\n");
+  printf(
+"  If you use Triangle, and especially if you use it to accomplish real\n");
+  printf(
+"  work, I would like very much to hear from you.  A short letter or email\n");
+  printf(
+"  (to jrs@cs.cmu.edu) describing how you use Triangle will mean a lot to\n");
+  printf(
+"  me.  The more people I know are using this program, the more easily I can\n"
+);
+  printf(
+"  justify spending time on improvements and on the three-dimensional\n");
+  printf(
+"  successor to Triangle, which in turn will benefit you.  Also, I can put\n");
+  printf(
+"  you on a list to receive email whenever a new version of Triangle is\n");
+  printf("  available.\n\n");
+  printf(
+"  If you use a mesh generated by Triangle in a publication, please include\n"
+);
+  printf("  an acknowledgment as well.\n\n");
+  printf("Research credit:\n\n");
+  printf(
+"  Of course, I can take credit for only a fraction of the ideas that made\n");
+  printf(
+"  this mesh generator possible.  Triangle owes its existence to the efforts\n"
+);
+  printf(
+"  of many fine computational geometers and other researchers, including\n");
+  printf(
+"  Marshall Bern, L. Paul Chew, Boris Delaunay, Rex A. Dwyer, David\n");
+  printf(
+"  Eppstein, Steven Fortune, Leonidas J. Guibas, Donald E. Knuth, C. L.\n");
+  printf(
+"  Lawson, Der-Tsai Lee, Ernst P. Mucke, Douglas M. Priest, Jim Ruppert,\n");
+  printf(
+"  Isaac Saias, Bruce J. Schachter, Micha Sharir, Jorge Stolfi, Christopher\n"
+);
+  printf(
+"  J. Van Wyk, David F. Watson, and Binhai Zhu.  See the comments at the\n");
+  printf("  beginning of the source code for references.\n\n");
+  exit(0);
+}
+
+#endif /* not TRILIBRARY */
+
+/*****************************************************************************/
+/*                                                                           */
+/*  internalerror()   Ask the user to send me the defective product.  Exit.  */
+/*                                                                           */
+/*****************************************************************************/
+
+void internalerror()
+{
+  printf("  Please report this bug to jrs@cs.cmu.edu\n");
+  printf("  Include the message above, your input data set, and the exact\n");
+  printf("    command line you used to run Triangle.\n");
+  exit(1);
+}
+
+/*****************************************************************************/
+/*                                                                           */
+/*  parsecommandline()   Read the command line, identify switches, and set   */
+/*                       up options and file names.                          */
+/*                                                                           */
+/*  The effects of this routine are felt entirely through global variables.  */
+/*                                                                           */
+/*****************************************************************************/
+
+void parsecommandline(argc, argv)
+int argc;
+char **argv;
+{
+#ifdef TRILIBRARY
+#define STARTINDEX 0
+#else /* not TRILIBRARY */
+#define STARTINDEX 1
+  int increment;
+  int meshnumber;
+#endif /* not TRILIBRARY */
+  int i, j, k;
+  char workstring[FILENAMESIZE];
+
+  poly = refine = quality = vararea = fixedarea = regionattrib = convex = 0;
+  firstnumber = 1;
+  edgesout = voronoi = neighbors = geomview = 0;
+  nobound = nopolywritten = nonodewritten = noelewritten = noiterationnum = 0;
+  noholes = noexact = 0;
+  incremental = sweepline = 0;
+  dwyer = 1;
+  splitseg = 0;
+  docheck = 0;
+  nobisect = 0;
+  steiner = -1;
+  order = 1;
+  minangle = 0.0;
+  maxarea = -1.0;
+  quiet = verbose = 0;
+#ifndef TRILIBRARY
+  innodefilename[0] = '\0';
+#endif /* not TRILIBRARY */
+
+  for (i = STARTINDEX; i < argc; i++) {
+#ifndef TRILIBRARY
+    if (argv[i][0] == '-') {
+#endif /* not TRILIBRARY */
+      for (j = STARTINDEX; argv[i][j] != '\0'; j++) {
+        if (argv[i][j] == 'p') {
+          poly = 1;
+       }
+#ifndef CDT_ONLY
+        if (argv[i][j] == 'r') {
+          refine = 1;
+       }
+        if (argv[i][j] == 'q') {
+          quality = 1;
+          if (((argv[i][j + 1] >= '0') && (argv[i][j + 1] <= '9')) ||
+              (argv[i][j + 1] == '.')) {
+            k = 0;
+            while (((argv[i][j + 1] >= '0') && (argv[i][j + 1] <= '9')) ||
+                   (argv[i][j + 1] == '.')) {
+              j++;
+              workstring[k] = argv[i][j];
+              k++;
+            }
+            workstring[k] = '\0';
+            minangle = (REAL) strtod(workstring, (char **) NULL);
+         } else {
+            minangle = 20.0;
+         }
+       }
+        if (argv[i][j] == 'a') {
+          quality = 1;
+          if (((argv[i][j + 1] >= '0') && (argv[i][j + 1] <= '9')) ||
+              (argv[i][j + 1] == '.')) {
+            fixedarea = 1;
+            k = 0;
+            while (((argv[i][j + 1] >= '0') && (argv[i][j + 1] <= '9')) ||
+                   (argv[i][j + 1] == '.')) {
+              j++;
+              workstring[k] = argv[i][j];
+              k++;
+            }
+            workstring[k] = '\0';
+            maxarea = (REAL) strtod(workstring, (char **) NULL);
+            if (maxarea <= 0.0) {
+              printf("Error:  Maximum area must be greater than zero.\n");
+              exit(1);
+           }
+         } else {
+            vararea = 1;
+         }
+       }
+#endif /* not CDT_ONLY */
+        if (argv[i][j] == 'A') {
+          regionattrib = 1;
+        }
+        if (argv[i][j] == 'c') {
+          convex = 1;
+        }
+        if (argv[i][j] == 'z') {
+          firstnumber = 0;
+        }
+        if (argv[i][j] == 'e') {
+          edgesout = 1;
+       }
+        if (argv[i][j] == 'v') {
+          voronoi = 1;
+       }
+        if (argv[i][j] == 'n') {
+          neighbors = 1;
+       }
+        if (argv[i][j] == 'g') {
+          geomview = 1;
+       }
+        if (argv[i][j] == 'B') {
+          nobound = 1;
+       }
+        if (argv[i][j] == 'P') {
+          nopolywritten = 1;
+       }
+        if (argv[i][j] == 'N') {
+          nonodewritten = 1;
+       }
+        if (argv[i][j] == 'E') {
+          noelewritten = 1;
+       }
+#ifndef TRILIBRARY
+        if (argv[i][j] == 'I') {
+          noiterationnum = 1;
+       }
+#endif /* not TRILIBRARY */
+        if (argv[i][j] == 'O') {
+          noholes = 1;
+       }
+        if (argv[i][j] == 'X') {
+          noexact = 1;
+       }
+        if (argv[i][j] == 'o') {
+          if (argv[i][j + 1] == '2') {
+            j++;
+            order = 2;
+          }
+       }
+#ifndef CDT_ONLY
+        if (argv[i][j] == 'Y') {
+          nobisect++;
+       }
+        if (argv[i][j] == 'S') {
+          steiner = 0;
+          while ((argv[i][j + 1] >= '0') && (argv[i][j + 1] <= '9')) {
+            j++;
+            steiner = steiner * 10 + (int) (argv[i][j] - '0');
+          }
+        }
+#endif /* not CDT_ONLY */
+#ifndef REDUCED
+        if (argv[i][j] == 'i') {
+          incremental = 1;
+        }
+        if (argv[i][j] == 'F') {
+          sweepline = 1;
+        }
+#endif /* not REDUCED */
+        if (argv[i][j] == 'l') {
+          dwyer = 0;
+        }
+#ifndef REDUCED
+#ifndef CDT_ONLY
+        if (argv[i][j] == 's') {
+          splitseg = 1;
+        }
+#endif /* not CDT_ONLY */
+        if (argv[i][j] == 'C') {
+          docheck = 1;
+        }
+#endif /* not REDUCED */
+        if (argv[i][j] == 'Q') {
+          quiet = 1;
+        }
+        if (argv[i][j] == 'V') {
+          verbose++;
+        }
+#ifndef TRILIBRARY
+        if ((argv[i][j] == 'h') || (argv[i][j] == 'H') ||
+            (argv[i][j] == '?')) {
+          info();
+       }
+#endif /* not TRILIBRARY */
+      }
+#ifndef TRILIBRARY
+    } else {
+      strncpy(innodefilename, argv[i], FILENAMESIZE - 1);
+      innodefilename[FILENAMESIZE - 1] = '\0';
+    }
+#endif /* not TRILIBRARY */
+  }
+#ifndef TRILIBRARY
+  if (innodefilename[0] == '\0') {
+    syntax();
+  }
+  if (!strcmp(&innodefilename[strlen(innodefilename) - 5], ".node")) {
+    innodefilename[strlen(innodefilename) - 5] = '\0';
+  }
+  if (!strcmp(&innodefilename[strlen(innodefilename) - 5], ".poly")) {
+    innodefilename[strlen(innodefilename) - 5] = '\0';
+    poly = 1;
+  }
+#ifndef CDT_ONLY
+  if (!strcmp(&innodefilename[strlen(innodefilename) - 4], ".ele")) {
+    innodefilename[strlen(innodefilename) - 4] = '\0';
+    refine = 1;
+  }
+  if (!strcmp(&innodefilename[strlen(innodefilename) - 5], ".area")) {
+    innodefilename[strlen(innodefilename) - 5] = '\0';
+    refine = 1;
+    quality = 1;
+    vararea = 1;
+  }
+#endif /* not CDT_ONLY */
+#endif /* not TRILIBRARY */
+  steinerleft = steiner;
+  useshelles = poly || refine || quality || convex;
+  goodangle = cos(minangle * PI / 180.0);
+  goodangle *= goodangle;
+  if (refine && noiterationnum) {
+    printf(
+      "Error:  You cannot use the -I switch when refining a triangulation.\n");
+    exit(1);
+  }
+  /* Be careful not to allocate space for element area constraints that */
+  /*   will never be assigned any value (other than the default -1.0).  */
+  if (!refine && !poly) {
+    vararea = 0;
+  }
+  /* Be careful not to add an extra attribute to each element unless the */
+  /*   input supports it (PSLG in, but not refining a preexisting mesh). */
+  if (refine || !poly) {
+    regionattrib = 0;
+  }
+
+#ifndef TRILIBRARY
+  strcpy(inpolyfilename, innodefilename);
+  strcpy(inelefilename, innodefilename);
+  strcpy(areafilename, innodefilename);
+  increment = 0;
+  strcpy(workstring, innodefilename);
+  j = 1;
+  while (workstring[j] != '\0') {
+    if ((workstring[j] == '.') && (workstring[j + 1] != '\0')) {
+      increment = j + 1;
+    }
+    j++;
+  }
+  meshnumber = 0;
+  if (increment > 0) {
+    j = increment;
+    do {
+      if ((workstring[j] >= '0') && (workstring[j] <= '9')) {
+        meshnumber = meshnumber * 10 + (int) (workstring[j] - '0');
+      } else {
+        increment = 0;
+      }
+      j++;
+    } while (workstring[j] != '\0');
+  }
+  if (noiterationnum) {
+    strcpy(outnodefilename, innodefilename);
+    strcpy(outelefilename, innodefilename);
+    strcpy(edgefilename, innodefilename);
+    strcpy(vnodefilename, innodefilename);
+    strcpy(vedgefilename, innodefilename);
+    strcpy(neighborfilename, innodefilename);
+    strcpy(offfilename, innodefilename);
+    strcat(outnodefilename, ".node");
+    strcat(outelefilename, ".ele");
+    strcat(edgefilename, ".edge");
+    strcat(vnodefilename, ".v.node");
+    strcat(vedgefilename, ".v.edge");
+    strcat(neighborfilename, ".neigh");
+    strcat(offfilename, ".off");
+  } else if (increment == 0) {
+    strcpy(outnodefilename, innodefilename);
+    strcpy(outpolyfilename, innodefilename);
+    strcpy(outelefilename, innodefilename);
+    strcpy(edgefilename, innodefilename);
+    strcpy(vnodefilename, innodefilename);
+    strcpy(vedgefilename, innodefilename);
+    strcpy(neighborfilename, innodefilename);
+    strcpy(offfilename, innodefilename);
+    strcat(outnodefilename, ".1.node");
+    strcat(outpolyfilename, ".1.poly");
+    strcat(outelefilename, ".1.ele");
+    strcat(edgefilename, ".1.edge");
+    strcat(vnodefilename, ".1.v.node");
+    strcat(vedgefilename, ".1.v.edge");
+    strcat(neighborfilename, ".1.neigh");
+    strcat(offfilename, ".1.off");
+  } else {
+    workstring[increment] = '%';
+    workstring[increment + 1] = 'd';
+    workstring[increment + 2] = '\0';
+    sprintf(outnodefilename, workstring, meshnumber + 1);
+    strcpy(outpolyfilename, outnodefilename);
+    strcpy(outelefilename, outnodefilename);
+    strcpy(edgefilename, outnodefilename);
+    strcpy(vnodefilename, outnodefilename);
+    strcpy(vedgefilename, outnodefilename);
+    strcpy(neighborfilename, outnodefilename);
+    strcpy(offfilename, outnodefilename);
+    strcat(outnodefilename, ".node");
+    strcat(outpolyfilename, ".poly");
+    strcat(outelefilename, ".ele");
+    strcat(edgefilename, ".edge");
+    strcat(vnodefilename, ".v.node");
+    strcat(vedgefilename, ".v.edge");
+    strcat(neighborfilename, ".neigh");
+    strcat(offfilename, ".off");
+  }
+  strcat(innodefilename, ".node");
+  strcat(inpolyfilename, ".poly");
+  strcat(inelefilename, ".ele");
+  strcat(areafilename, ".area");
+#endif /* not TRILIBRARY */
+}
+
+/**                                                                         **/
+/**                                                                         **/
+/********* User interaction routines begin here                      *********/
+
+/********* Debugging routines begin here                             *********/
+/**                                                                         **/
+/**                                                                         **/
+
+/*****************************************************************************/
+/*                                                                           */
+/*  printtriangle()   Print out the details of a triangle/edge handle.       */
+/*                                                                           */
+/*  I originally wrote this procedure to simplify debugging; it can be       */
+/*  called directly from the debugger, and presents information about a      */
+/*  triangle/edge handle in digestible form.  It's also used when the        */
+/*  highest level of verbosity (`-VVV') is specified.                        */
+/*                                                                           */
+/*****************************************************************************/
+
+void printtriangle(t)
+struct triedge *t;
+{
+  struct triedge printtri;
+  struct edge printsh;
+  point printpoint;
+
+  printf("triangle x%lx with orientation %d:\n", (unsigned long) t->tri,
+         t->orient);
+  decode(t->tri[0], printtri);
+  if (printtri.tri == dummytri) {
+    printf("    [0] = Outer space\n");
+  } else {
+    printf("    [0] = x%lx  %d\n", (unsigned long) printtri.tri,
+           printtri.orient);
+  }
+  decode(t->tri[1], printtri);
+  if (printtri.tri == dummytri) {
+    printf("    [1] = Outer space\n");
+  } else {
+    printf("    [1] = x%lx  %d\n", (unsigned long) printtri.tri,
+           printtri.orient);
+  }
+  decode(t->tri[2], printtri);
+  if (printtri.tri == dummytri) {
+    printf("    [2] = Outer space\n");
+  } else {
+    printf("    [2] = x%lx  %d\n", (unsigned long) printtri.tri,
+           printtri.orient);
+  }
+  org(*t, printpoint);
+  if (printpoint == (point) NULL)
+    printf("    Origin[%d] = NULL\n", (t->orient + 1) % 3 + 3);
+  else
+    printf("    Origin[%d] = x%lx  (%.12g, %.12g)\n",
+           (t->orient + 1) % 3 + 3, (unsigned long) printpoint,
+           printpoint[0], printpoint[1]);
+  dest(*t, printpoint);
+  if (printpoint == (point) NULL)
+    printf("    Dest  [%d] = NULL\n", (t->orient + 2) % 3 + 3);
+  else
+    printf("    Dest  [%d] = x%lx  (%.12g, %.12g)\n",
+           (t->orient + 2) % 3 + 3, (unsigned long) printpoint,
+           printpoint[0], printpoint[1]);
+  apex(*t, printpoint);
+  if (printpoint == (point) NULL)
+    printf("    Apex  [%d] = NULL\n", t->orient + 3);
+  else
+    printf("    Apex  [%d] = x%lx  (%.12g, %.12g)\n",
+           t->orient + 3, (unsigned long) printpoint,
+           printpoint[0], printpoint[1]);
+  if (useshelles) {
+    sdecode(t->tri[6], printsh);
+    if (printsh.sh != dummysh) {
+      printf("    [6] = x%lx  %d\n", (unsigned long) printsh.sh,
+             printsh.shorient);
+    }
+    sdecode(t->tri[7], printsh);
+    if (printsh.sh != dummysh) {
+      printf("    [7] = x%lx  %d\n", (unsigned long) printsh.sh,
+             printsh.shorient);
+    }
+    sdecode(t->tri[8], printsh);
+    if (printsh.sh != dummysh) {
+      printf("    [8] = x%lx  %d\n", (unsigned long) printsh.sh,
+             printsh.shorient);
+    }
+  }
+  if (vararea) {
+    printf("    Area constraint:  %.4g\n", areabound(*t));
+  }
+}
+
+/*****************************************************************************/
+/*                                                                           */
+/*  printshelle()   Print out the details of a shell edge handle.            */
+/*                                                                           */
+/*  I originally wrote this procedure to simplify debugging; it can be       */
+/*  called directly from the debugger, and presents information about a      */
+/*  shell edge handle in digestible form.  It's also used when the highest   */
+/*  level of verbosity (`-VVV') is specified.                                */
+/*                                                                           */
+/*****************************************************************************/
+
+void printshelle(s)
+struct edge *s;
+{
+  struct edge printsh;
+  struct triedge printtri;
+  point printpoint;
+
+  printf("shell edge x%lx with orientation %d and mark %d:\n",
+         (unsigned long) s->sh, s->shorient, mark(*s));
+  sdecode(s->sh[0], printsh);
+  if (printsh.sh == dummysh) {
+    printf("    [0] = No shell\n");
+  } else {
+    printf("    [0] = x%lx  %d\n", (unsigned long) printsh.sh,
+           printsh.shorient);
+  }
+  sdecode(s->sh[1], printsh);
+  if (printsh.sh == dummysh) {
+    printf("    [1] = No shell\n");
+  } else {
+    printf("    [1] = x%lx  %d\n", (unsigned long) printsh.sh,
+           printsh.shorient);
+  }
+  sorg(*s, printpoint);
+  if (printpoint == (point) NULL)
+    printf("    Origin[%d] = NULL\n", 2 + s->shorient);
+  else
+    printf("    Origin[%d] = x%lx  (%.12g, %.12g)\n",
+           2 + s->shorient, (unsigned long) printpoint,
+           printpoint[0], printpoint[1]);
+  sdest(*s, printpoint);
+  if (printpoint == (point) NULL)
+    printf("    Dest  [%d] = NULL\n", 3 - s->shorient);
+  else
+    printf("    Dest  [%d] = x%lx  (%.12g, %.12g)\n",
+           3 - s->shorient, (unsigned long) printpoint,
+           printpoint[0], printpoint[1]);
+  decode(s->sh[4], printtri);
+  if (printtri.tri == dummytri) {
+    printf("    [4] = Outer space\n");
+  } else {
+    printf("    [4] = x%lx  %d\n", (unsigned long) printtri.tri,
+           printtri.orient);
+  }
+  decode(s->sh[5], printtri);
+  if (printtri.tri == dummytri) {
+    printf("    [5] = Outer space\n");
+  } else {
+    printf("    [5] = x%lx  %d\n", (unsigned long) printtri.tri,
+           printtri.orient);
+  }
+}
+
+/**                                                                         **/
+/**                                                                         **/
+/********* Debugging routines end here                               *********/
+
+/********* Memory management routines begin here                     *********/
+/**                                                                         **/
+/**                                                                         **/
+
+/*****************************************************************************/
+/*                                                                           */
+/*  poolinit()   Initialize a pool of memory for allocation of items.        */
+/*                                                                           */
+/*  This routine initializes the machinery for allocating items.  A `pool'   */
+/*  is created whose records have size at least `bytecount'.  Items will be  */
+/*  allocated in `itemcount'-item blocks.  Each item is assumed to be a      */
+/*  collection of words, and either pointers or floating-point values are    */
+/*  assumed to be the "primary" word type.  (The "primary" word type is used */
+/*  to determine alignment of items.)  If `alignment' isn't zero, all items  */
+/*  will be `alignment'-byte aligned in memory.  `alignment' must be either  */
+/*  a multiple or a factor of the primary word size; powers of two are safe. */
+/*  `alignment' is normally used to create a few unused bits at the bottom   */
+/*  of each item's pointer, in which information may be stored.              */
+/*                                                                           */
+/*  Don't change this routine unless you understand it.                      */
+/*                                                                           */
+/*****************************************************************************/
+
+void poolinit(pool, bytecount, itemcount, wtype, alignment)
+struct memorypool *pool;
+int bytecount;
+int itemcount;
+enum wordtype wtype;
+int alignment;
+{
+  int wordsize;
+
+  /* Initialize values in the pool. */
+  pool->itemwordtype = wtype;
+  wordsize = (pool->itemwordtype == POINTER) ? sizeof(VOID *) : sizeof(REAL);
+  /* Find the proper alignment, which must be at least as large as:   */
+  /*   - The parameter `alignment'.                                   */
+  /*   - The primary word type, to avoid unaligned accesses.          */
+  /*   - sizeof(VOID *), so the stack of dead items can be maintained */
+  /*       without unaligned accesses.                                */
+  if (alignment > wordsize) {
+    pool->alignbytes = alignment;
+  } else {
+    pool->alignbytes = wordsize;
+  }
+  if (sizeof(VOID *) > pool->alignbytes) {
+    pool->alignbytes = sizeof(VOID *);
+  }
+  pool->itemwords = ((bytecount + pool->alignbytes - 1) / pool->alignbytes)
+                  * (pool->alignbytes / wordsize);
+  pool->itembytes = pool->itemwords * wordsize;
+  pool->itemsperblock = itemcount;
+
+  /* Allocate a block of items.  Space for `itemsperblock' items and one    */
+  /*   pointer (to point to the next block) are allocated, as well as space */
+  /*   to ensure alignment of the items.                                    */
+  pool->firstblock = (VOID **) malloc(pool->itemsperblock * pool->itembytes
+                                      + sizeof(VOID *) + pool->alignbytes);
+  if (pool->firstblock == (VOID **) NULL) {
+    printf("Error:  Out of memory.\n");
+    exit(1);
+  }
+  /* Set the next block pointer to NULL. */
+  *(pool->firstblock) = (VOID *) NULL;
+  poolrestart(pool);
+}
+
+/*****************************************************************************/
+/*                                                                           */
+/*  poolrestart()   Deallocate all items in a pool.                          */
+/*                                                                           */
+/*  The pool is returned to its starting state, except that no memory is     */
+/*  freed to the operating system.  Rather, the previously allocated blocks  */
+/*  are ready to be reused.                                                  */
+/*                                                                           */
+/*****************************************************************************/
+
+void poolrestart(pool)
+struct memorypool *pool;
+{
+  unsigned long alignptr;
+
+  pool->items = 0;
+  pool->maxitems = 0;
+
+  /* Set the currently active block. */
+  pool->nowblock = pool->firstblock;
+  /* Find the first item in the pool.  Increment by the size of (VOID *). */
+  alignptr = (unsigned long) (pool->nowblock + 1);
+  /* Align the item on an `alignbytes'-byte boundary. */
+  pool->nextitem = (VOID *)
+    (alignptr + (unsigned long) pool->alignbytes
+     - (alignptr % (unsigned long) pool->alignbytes));
+  /* There are lots of unallocated items left in this block. */
+  pool->unallocateditems = pool->itemsperblock;
+  /* The stack of deallocated items is empty. */
+  pool->deaditemstack = (VOID *) NULL;
+}
+
+/*****************************************************************************/
+/*                                                                           */
+/*  pooldeinit()   Free to the operating system all memory taken by a pool.  */
+/*                                                                           */
+/*****************************************************************************/
+
+void pooldeinit(pool)
+struct memorypool *pool;
+{
+  while (pool->firstblock != (VOID **) NULL) {
+    pool->nowblock = (VOID **) *(pool->firstblock);
+    free(pool->firstblock);
+    pool->firstblock = pool->nowblock;
+  }
+}
+
+/*****************************************************************************/
+/*                                                                           */
+/*  poolalloc()   Allocate space for an item.                                */
+/*                                                                           */
+/*****************************************************************************/
+
+VOID *poolalloc(pool)
+struct memorypool *pool;
+{
+  VOID *newitem;
+  VOID **newblock;
+  unsigned long alignptr;
+
+  /* First check the linked list of dead items.  If the list is not   */
+  /*   empty, allocate an item from the list rather than a fresh one. */
+  if (pool->deaditemstack != (VOID *) NULL) {
+    newitem = pool->deaditemstack;               /* Take first item in list. */
+    pool->deaditemstack = * (VOID **) pool->deaditemstack;
+  } else {
+    /* Check if there are any free items left in the current block. */
+    if (pool->unallocateditems == 0) {
+      /* Check if another block must be allocated. */
+      if (*(pool->nowblock) == (VOID *) NULL) {
+        /* Allocate a new block of items, pointed to by the previous block. */
+        newblock = (VOID **) malloc(pool->itemsperblock * pool->itembytes
+                                    + sizeof(VOID *) + pool->alignbytes);
+        if (newblock == (VOID **) NULL) {
+          printf("Error:  Out of memory.\n");
+          exit(1);
+        }
+        *(pool->nowblock) = (VOID *) newblock;
+        /* The next block pointer is NULL. */
+        *newblock = (VOID *) NULL;
+      }
+      /* Move to the new block. */
+      pool->nowblock = (VOID **) *(pool->nowblock);
+      /* Find the first item in the block.    */
+      /*   Increment by the size of (VOID *). */
+      alignptr = (unsigned long) (pool->nowblock + 1);
+      /* Align the item on an `alignbytes'-byte boundary. */
+      pool->nextitem = (VOID *)
+        (alignptr + (unsigned long) pool->alignbytes
+         - (alignptr % (unsigned long) pool->alignbytes));
+      /* There are lots of unallocated items left in this block. */
+      pool->unallocateditems = pool->itemsperblock;
+    }
+    /* Allocate a new item. */
+    newitem = pool->nextitem;
+    /* Advance `nextitem' pointer to next free item in block. */
+    if (pool->itemwordtype == POINTER) {
+      pool->nextitem = (VOID *) ((VOID **) pool->nextitem + pool->itemwords);
+    } else {
+      pool->nextitem = (VOID *) ((REAL *) pool->nextitem + pool->itemwords);
+    }
+    pool->unallocateditems--;
+    pool->maxitems++;
+  }
+  pool->items++;
+  return newitem;
+}
+
+/*****************************************************************************/
+/*                                                                           */
+/*  pooldealloc()   Deallocate space for an item.                            */
+/*                                                                           */
+/*  The deallocated space is stored in a queue for later reuse.              */
+/*                                                                           */
+/*****************************************************************************/
+
+void pooldealloc(pool, dyingitem)
+struct memorypool *pool;
+VOID *dyingitem;
+{
+  /* Push freshly killed item onto stack. */
+  *((VOID **) dyingitem) = pool->deaditemstack;
+  pool->deaditemstack = dyingitem;
+  pool->items--;
+}
+
+/*****************************************************************************/
+/*                                                                           */
+/*  traversalinit()   Prepare to traverse the entire list of items.          */
+/*                                                                           */
+/*  This routine is used in conjunction with traverse().                     */
+/*                                                                           */
+/*****************************************************************************/
+
+void traversalinit(pool)
+struct memorypool *pool;
+{
+  unsigned long alignptr;
+
+  /* Begin the traversal in the first block. */
+  pool->pathblock = pool->firstblock;
+  /* Find the first item in the block.  Increment by the size of (VOID *). */
+  alignptr = (unsigned long) (pool->pathblock + 1);
+  /* Align with item on an `alignbytes'-byte boundary. */
+  pool->pathitem = (VOID *)
+    (alignptr + (unsigned long) pool->alignbytes
+     - (alignptr % (unsigned long) pool->alignbytes));
+  /* Set the number of items left in the current block. */
+  pool->pathitemsleft = pool->itemsperblock;
+}
+
+/*****************************************************************************/
+/*                                                                           */
+/*  traverse()   Find the next item in the list.                             */
+/*                                                                           */
+/*  This routine is used in conjunction with traversalinit().  Be forewarned */
+/*  that this routine successively returns all items in the list, including  */
+/*  deallocated ones on the deaditemqueue.  It's up to you to figure out     */
+/*  which ones are actually dead.  Why?  I don't want to allocate extra      */
+/*  space just to demarcate dead items.  It can usually be done more         */
+/*  space-efficiently by a routine that knows something about the structure  */
+/*  of the item.                                                             */
+/*                                                                           */
+/*****************************************************************************/
+
+VOID *traverse(pool)
+struct memorypool *pool;
+{
+  VOID *newitem;
+  unsigned long alignptr;
+
+  /* Stop upon exhausting the list of items. */
+  if (pool->pathitem == pool->nextitem) {
+    return (VOID *) NULL;
+  }
+  /* Check whether any untraversed items remain in the current block. */
+  if (pool->pathitemsleft == 0) {
+    /* Find the next block. */
+    pool->pathblock = (VOID **) *(pool->pathblock);
+    /* Find the first item in the block.  Increment by the size of (VOID *). */
+    alignptr = (unsigned long) (pool->pathblock + 1);
+    /* Align with item on an `alignbytes'-byte boundary. */
+    pool->pathitem = (VOID *)
+      (alignptr + (unsigned long) pool->alignbytes
+       - (alignptr % (unsigned long) pool->alignbytes));
+    /* Set the number of items left in the current block. */
+    pool->pathitemsleft = pool->itemsperblock;
+  }
+  newitem = pool->pathitem;
+  /* Find the next item in the block. */
+  if (pool->itemwordtype == POINTER) {
+    pool->pathitem = (VOID *) ((VOID **) pool->pathitem + pool->itemwords);
+  } else {
+    pool->pathitem = (VOID *) ((REAL *) pool->pathitem + pool->itemwords);
+  }
+  pool->pathitemsleft--;
+  return newitem;
+}
+
+/*****************************************************************************/
+/*                                                                           */
+/*  dummyinit()   Initialize the triangle that fills "outer space" and the   */
+/*                omnipresent shell edge.                                    */
+/*                                                                           */
+/*  The triangle that fills "outer space", called `dummytri', is pointed to  */
+/*  by every triangle and shell edge on a boundary (be it outer or inner) of */
+/*  the triangulation.  Also, `dummytri' points to one of the triangles on   */
+/*  the convex hull (until the holes and concavities are carved), making it  */
+/*  possible to find a starting triangle for point location.                 */
+/*                                                                           */
+/*  The omnipresent shell edge, `dummysh', is pointed to by every triangle   */
+/*  or shell edge that doesn't have a full complement of real shell edges    */
+/*  to point to.                                                             */
+/*                                                                           */
+/*****************************************************************************/
+
+void dummyinit(trianglewords, shellewords)
+int trianglewords;
+int shellewords;
+{
+  unsigned long alignptr;
+
+  /* `triwords' and `shwords' are used by the mesh manipulation primitives */
+  /*   to extract orientations of triangles and shell edges from pointers. */
+  triwords = trianglewords;       /* Initialize `triwords' once and for all. */
+  shwords = shellewords;           /* Initialize `shwords' once and for all. */
+
+  /* Set up `dummytri', the `triangle' that occupies "outer space". */
+  dummytribase = (triangle *) malloc(triwords * sizeof(triangle)
+                                     + triangles.alignbytes);
+  if (dummytribase == (triangle *) NULL) {
+    printf("Error:  Out of memory.\n");
+    exit(1);
+  }
+  /* Align `dummytri' on a `triangles.alignbytes'-byte boundary. */
+  alignptr = (unsigned long) dummytribase;
+  dummytri = (triangle *)
+    (alignptr + (unsigned long) triangles.alignbytes
+     - (alignptr % (unsigned long) triangles.alignbytes));
+  /* Initialize the three adjoining triangles to be "outer space".  These  */
+  /*   will eventually be changed by various bonding operations, but their */
+  /*   values don't really matter, as long as they can legally be          */
+  /*   dereferenced.                                                       */
+  dummytri[0] = (triangle) dummytri;
+  dummytri[1] = (triangle) dummytri;
+  dummytri[2] = (triangle) dummytri;
+  /* Three NULL vertex points. */
+  dummytri[3] = (triangle) NULL;
+  dummytri[4] = (triangle) NULL;
+  dummytri[5] = (triangle) NULL;
+
+  if (useshelles) {
+    /* Set up `dummysh', the omnipresent "shell edge" pointed to by any      */
+    /*   triangle side or shell edge end that isn't attached to a real shell */
+    /*   edge.                                                               */
+    dummyshbase = (shelle *) malloc(shwords * sizeof(shelle)
+                                    + shelles.alignbytes);
+    if (dummyshbase == (shelle *) NULL) {
+      printf("Error:  Out of memory.\n");
+      exit(1);
+    }
+    /* Align `dummysh' on a `shelles.alignbytes'-byte boundary. */
+    alignptr = (unsigned long) dummyshbase;
+    dummysh = (shelle *)
+      (alignptr + (unsigned long) shelles.alignbytes
+       - (alignptr % (unsigned long) shelles.alignbytes));
+    /* Initialize the two adjoining shell edges to be the omnipresent shell */
+    /*   edge.  These will eventually be changed by various bonding         */
+    /*   operations, but their values don't really matter, as long as they  */
+    /*   can legally be dereferenced.                                       */
+    dummysh[0] = (shelle) dummysh;
+    dummysh[1] = (shelle) dummysh;
+    /* Two NULL vertex points. */
+    dummysh[2] = (shelle) NULL;
+    dummysh[3] = (shelle) NULL;
+    /* Initialize the two adjoining triangles to be "outer space". */
+    dummysh[4] = (shelle) dummytri;
+    dummysh[5] = (shelle) dummytri;
+    /* Set the boundary marker to zero. */
+    * (int *) (dummysh + 6) = 0;
+
+    /* Initialize the three adjoining shell edges of `dummytri' to be */
+    /*   the omnipresent shell edge.                                  */
+    dummytri[6] = (triangle) dummysh;
+    dummytri[7] = (triangle) dummysh;
+    dummytri[8] = (triangle) dummysh;
+  }
+}
+
+/*****************************************************************************/
+/*                                                                           */
+/*  initializepointpool()   Calculate the size of the point data structure   */
+/*                          and initialize its memory pool.                  */
+/*                                                                           */
+/*  This routine also computes the `pointmarkindex' and `point2triindex'     */
+/*  indices used to find values within each point.                           */
+/*                                                                           */
+/*****************************************************************************/
+
+void initializepointpool()
+{
+  int pointsize;
+
+  /* The index within each point at which the boundary marker is found.  */
+  /*   Ensure the point marker is aligned to a sizeof(int)-byte address. */
+  pointmarkindex = ((mesh_dim + nextras) * sizeof(REAL) + sizeof(int) - 1)
+                 / sizeof(int);
+  pointsize = (pointmarkindex + 1) * sizeof(int);
+  if (poly) {
+    /* The index within each point at which a triangle pointer is found.   */
+    /*   Ensure the pointer is aligned to a sizeof(triangle)-byte address. */
+    point2triindex = (pointsize + sizeof(triangle) - 1) / sizeof(triangle);
+    pointsize = (point2triindex + 1) * sizeof(triangle);
+  }
+  /* Initialize the pool of points. */
+  poolinit(&points, pointsize, POINTPERBLOCK,
+           (sizeof(REAL) >= sizeof(triangle)) ? FLOATINGPOINT : POINTER, 0);
+}
+
+/*****************************************************************************/
+/*                                                                           */
+/*  initializetrisegpools()   Calculate the sizes of the triangle and shell  */
+/*                            edge data structures and initialize their      */
+/*                            memory pools.                                  */
+/*                                                                           */
+/*  This routine also computes the `highorderindex', `elemattribindex', and  */
+/*  `areaboundindex' indices used to find values within each triangle.       */
+/*                                                                           */
+/*****************************************************************************/
+
+void initializetrisegpools()
+{
+  int trisize;
+
+  /* The index within each triangle at which the extra nodes (above three)  */
+  /*   associated with high order elements are found.  There are three      */
+  /*   pointers to other triangles, three pointers to corners, and possibly */
+  /*   three pointers to shell edges before the extra nodes.                */
+  highorderindex = 6 + (useshelles * 3);
+  /* The number of bytes occupied by a triangle. */
+  trisize = ((order + 1) * (order + 2) / 2 + (highorderindex - 3)) *
+            sizeof(triangle);
+  /* The index within each triangle at which its attributes are found, */
+  /*   where the index is measured in REALs.                           */
+  elemattribindex = (trisize + sizeof(REAL) - 1) / sizeof(REAL);
+  /* The index within each triangle at which the maximum area constraint  */
+  /*   is found, where the index is measured in REALs.  Note that if the  */
+  /*   `regionattrib' flag is set, an additional attribute will be added. */
+  areaboundindex = elemattribindex + eextras + regionattrib;
+  /* If triangle attributes or an area bound are needed, increase the number */
+  /*   of bytes occupied by a triangle.                                      */
+  if (vararea) {
+    trisize = (areaboundindex + 1) * sizeof(REAL);
+  } else if (eextras + regionattrib > 0) {
+    trisize = areaboundindex * sizeof(REAL);
+  }
+  /* If a Voronoi diagram or triangle neighbor graph is requested, make    */
+  /*   sure there's room to store an integer index in each triangle.  This */
+  /*   integer index can occupy the same space as the shell edges or       */
+  /*   attributes or area constraint or extra nodes.                       */
+  if ((voronoi || neighbors) &&
+      (trisize < 6 * sizeof(triangle) + sizeof(int))) {
+    trisize = 6 * sizeof(triangle) + sizeof(int);
+  }
+  /* Having determined the memory size of a triangle, initialize the pool. */
+  poolinit(&triangles, trisize, TRIPERBLOCK, POINTER, 4);
+
+  if (useshelles) {
+    /* Initialize the pool of shell edges. */
+    poolinit(&shelles, 6 * sizeof(triangle) + sizeof(int), SHELLEPERBLOCK,
+             POINTER, 4);
+
+    /* Initialize the "outer space" triangle and omnipresent shell edge. */
+    dummyinit(triangles.itemwords, shelles.itemwords);
+  } else {
+    /* Initialize the "outer space" triangle. */
+    dummyinit(triangles.itemwords, 0);
+  }
+}
+
+/*****************************************************************************/
+/*                                                                           */
+/*  triangledealloc()   Deallocate space for a triangle, marking it dead.    */
+/*                                                                           */
+/*****************************************************************************/
+
+void triangledealloc(dyingtriangle)
+triangle *dyingtriangle;
+{
+  /* Set triangle's vertices to NULL.  This makes it possible to        */
+  /*   detect dead triangles when traversing the list of all triangles. */
+  dyingtriangle[3] = (triangle) NULL;
+  dyingtriangle[4] = (triangle) NULL;
+  dyingtriangle[5] = (triangle) NULL;
+  pooldealloc(&triangles, (VOID *) dyingtriangle);
+}
+
+/*****************************************************************************/
+/*                                                                           */
+/*  triangletraverse()   Traverse the triangles, skipping dead ones.         */
+/*                                                                           */
+/*****************************************************************************/
+
+triangle *triangletraverse()
+{
+  triangle *newtriangle;
+
+  do {
+    newtriangle = (triangle *) traverse(&triangles);
+    if (newtriangle == (triangle *) NULL) {
+      return (triangle *) NULL;
+    }
+  } while (newtriangle[3] == (triangle) NULL);            /* Skip dead ones. */
+  return newtriangle;
+}
+
+/*****************************************************************************/
+/*                                                                           */
+/*  shelledealloc()   Deallocate space for a shell edge, marking it dead.    */
+/*                                                                           */
+/*****************************************************************************/
+
+void shelledealloc(dyingshelle)
+shelle *dyingshelle;
+{
+  /* Set shell edge's vertices to NULL.  This makes it possible to */
+  /*   detect dead shells when traversing the list of all shells.  */
+  dyingshelle[2] = (shelle) NULL;
+  dyingshelle[3] = (shelle) NULL;
+  pooldealloc(&shelles, (VOID *) dyingshelle);
+}
+
+/*****************************************************************************/
+/*                                                                           */
+/*  shelletraverse()   Traverse the shell edges, skipping dead ones.         */
+/*                                                                           */
+/*****************************************************************************/
+
+shelle *shelletraverse()
+{
+  shelle *newshelle;
+
+  do {
+    newshelle = (shelle *) traverse(&shelles);
+    if (newshelle == (shelle *) NULL) {
+      return (shelle *) NULL;
+    }
+  } while (newshelle[2] == (shelle) NULL);                /* Skip dead ones. */
+  return newshelle;
+}
+
+/*****************************************************************************/
+/*                                                                           */
+/*  pointdealloc()   Deallocate space for a point, marking it dead.          */
+/*                                                                           */
+/*****************************************************************************/
+
+void pointdealloc(dyingpoint)
+point dyingpoint;
+{
+  /* Mark the point as dead.  This makes it possible to detect dead points */
+  /*   when traversing the list of all points.                             */
+  setpointmark(dyingpoint, DEADPOINT);
+  pooldealloc(&points, (VOID *) dyingpoint);
+}
+
+/*****************************************************************************/
+/*                                                                           */
+/*  pointtraverse()   Traverse the points, skipping dead ones.               */
+/*                                                                           */
+/*****************************************************************************/
+
+point pointtraverse()
+{
+  point newpoint;
+
+  do {
+    newpoint = (point) traverse(&points);
+    if (newpoint == (point) NULL) {
+      return (point) NULL;
+    }
+  } while (pointmark(newpoint) == DEADPOINT);             /* Skip dead ones. */
+  return newpoint;
+}
+
+/*****************************************************************************/
+/*                                                                           */
+/*  badsegmentdealloc()   Deallocate space for a bad segment, marking it     */
+/*                        dead.                                              */
+/*                                                                           */
+/*****************************************************************************/
+
+#ifndef CDT_ONLY
+
+void badsegmentdealloc(dyingseg)
+struct edge *dyingseg;
+{
+  /* Set segment's orientation to -1.  This makes it possible to      */
+  /*   detect dead segments when traversing the list of all segments. */
+  dyingseg->shorient = -1;
+  pooldealloc(&badsegments, (VOID *) dyingseg);
+}
+
+#endif /* not CDT_ONLY */
+
+/*****************************************************************************/
+/*                                                                           */
+/*  badsegmenttraverse()   Traverse the bad segments, skipping dead ones.    */
+/*                                                                           */
+/*****************************************************************************/
+
+#ifndef CDT_ONLY
+
+struct edge *badsegmenttraverse()
+{
+  struct edge *newseg;
+
+  do {
+    newseg = (struct edge *) traverse(&badsegments);
+    if (newseg == (struct edge *) NULL) {
+      return (struct edge *) NULL;
+    }
+  } while (newseg->shorient == -1);                       /* Skip dead ones. */
+  return newseg;
+}
+
+#endif /* not CDT_ONLY */
+
+/*****************************************************************************/
+/*                                                                           */
+/*  getpoint()   Get a specific point, by number, from the list.             */
+/*                                                                           */
+/*  The first point is number 'firstnumber'.                                 */
+/*                                                                           */
+/*  Note that this takes O(n) time (with a small constant, if POINTPERBLOCK  */
+/*  is large).  I don't care to take the trouble to make it work in constant */
+/*  time.                                                                    */
+/*                                                                           */
+/*****************************************************************************/
+
+point getpoint(number)
+int number;
+{
+  VOID **getblock;
+  point foundpoint;
+  unsigned long alignptr;
+  int current;
+
+  getblock = points.firstblock;
+  current = firstnumber;
+  /* Find the right block. */
+  while (current + points.itemsperblock <= number) {
+    getblock = (VOID **) *getblock;
+    current += points.itemsperblock;
+  }
+  /* Now find the right point. */
+  alignptr = (unsigned long) (getblock + 1);
+  foundpoint = (point) (alignptr + (unsigned long) points.alignbytes
+                        - (alignptr % (unsigned long) points.alignbytes));
+  while (current < number) {
+    foundpoint += points.itemwords;
+    current++;
+  }
+  return foundpoint;
+}
+
+/*****************************************************************************/
+/*                                                                           */
+/*  triangledeinit()   Free all remaining allocated memory.                  */
+/*                                                                           */
+/*****************************************************************************/
+
+void triangledeinit()
+{
+  pooldeinit(&triangles);
+  free(dummytribase);
+  if (useshelles) {
+    pooldeinit(&shelles);
+    free(dummyshbase);
+  }
+  pooldeinit(&points);
+#ifndef CDT_ONLY
+  if (quality) {
+    pooldeinit(&badsegments);
+    if ((minangle > 0.0) || vararea || fixedarea) {
+      pooldeinit(&badtriangles);
+    }
+  }
+#endif /* not CDT_ONLY */
+}
+
+/**                                                                         **/
+/**                                                                         **/
+/********* Memory management routines end here                       *********/
+
+/********* Constructors begin here                                   *********/
+/**                                                                         **/
+/**                                                                         **/
+
+/*****************************************************************************/
+/*                                                                           */
+/*  maketriangle()   Create a new triangle with orientation zero.            */
+/*                                                                           */
+/*****************************************************************************/
+
+void maketriangle(newtriedge)
+struct triedge *newtriedge;
+{
+  int i;
+
+  newtriedge->tri = (triangle *) poolalloc(&triangles);
+  /* Initialize the three adjoining triangles to be "outer space". */
+  newtriedge->tri[0] = (triangle) dummytri;
+  newtriedge->tri[1] = (triangle) dummytri;
+  newtriedge->tri[2] = (triangle) dummytri;
+  /* Three NULL vertex points. */
+  newtriedge->tri[3] = (triangle) NULL;
+  newtriedge->tri[4] = (triangle) NULL;
+  newtriedge->tri[5] = (triangle) NULL;
+  /* Initialize the three adjoining shell edges to be the omnipresent */
+  /*   shell edge.                                                    */
+  if (useshelles) {
+    newtriedge->tri[6] = (triangle) dummysh;
+    newtriedge->tri[7] = (triangle) dummysh;
+    newtriedge->tri[8] = (triangle) dummysh;
+  }
+  for (i = 0; i < eextras; i++) {
+    setelemattribute(*newtriedge, i, 0.0);
+  }
+  if (vararea) {
+    setareabound(*newtriedge, -1.0);
+  }
+
+  newtriedge->orient = 0;
+}
+
+/*****************************************************************************/
+/*                                                                           */
+/*  makeshelle()   Create a new shell edge with orientation zero.            */
+/*                                                                           */
+/*****************************************************************************/
+
+void makeshelle(newedge)
+struct edge *newedge;
+{
+  newedge->sh = (shelle *) poolalloc(&shelles);
+  /* Initialize the two adjoining shell edges to be the omnipresent */
+  /*   shell edge.                                                  */
+  newedge->sh[0] = (shelle) dummysh;
+  newedge->sh[1] = (shelle) dummysh;
+  /* Two NULL vertex points. */
+  newedge->sh[2] = (shelle) NULL;
+  newedge->sh[3] = (shelle) NULL;
+  /* Initialize the two adjoining triangles to be "outer space". */
+  newedge->sh[4] = (shelle) dummytri;
+  newedge->sh[5] = (shelle) dummytri;
+  /* Set the boundary marker to zero. */
+  setmark(*newedge, 0);
+
+  newedge->shorient = 0;
+}
+
+/**                                                                         **/
+/**                                                                         **/
+/********* Constructors end here                                     *********/
+
+/********* Determinant evaluation routines begin here                *********/
+/**                                                                         **/
+/**                                                                         **/
+
+/* The adaptive exact arithmetic geometric predicates implemented herein are */
+/*   described in detail in my Technical Report CMU-CS-96-140.  The complete */
+/*   reference is given in the header.                                       */
+
+/* Which of the following two methods of finding the absolute values is      */
+/*   fastest is compiler-dependent.  A few compilers can inline and optimize */
+/*   the fabs() call; but most will incur the overhead of a function call,   */
+/*   which is disastrously slow.  A faster way on IEEE machines might be to  */
+/*   mask the appropriate bit, but that's difficult to do in C.              */
+
+#define Absolute(a)  ((a) >= 0.0 ? (a) : -(a))
+/* #define Absolute(a)  fabs(a) */
+
+/* Many of the operations are broken up into two pieces, a main part that    */
+/*   performs an approximate operation, and a "tail" that computes the       */
+/*   roundoff error of that operation.                                       */
+/*                                                                           */
+/* The operations Fast_Two_Sum(), Fast_Two_Diff(), Two_Sum(), Two_Diff(),    */
+/*   Split(), and Two_Product() are all implemented as described in the      */
+/*   reference.  Each of these macros requires certain variables to be       */
+/*   defined in the calling routine.  The variables `bvirt', `c', `abig',    */
+/*   `_i', `_j', `_k', `_l', `_m', and `_n' are declared `INEXACT' because   */
+/*   they store the result of an operation that may incur roundoff error.    */
+/*   The input parameter `x' (or the highest numbered `x_' parameter) must   */
+/*   also be declared `INEXACT'.                                             */
+
+#define Fast_Two_Sum_Tail(a, b, x, y) \
+  bvirt = x - a; \
+  y = b - bvirt
+
+#define Fast_Two_Sum(a, b, x, y) \
+  x = (REAL) (a + b); \
+  Fast_Two_Sum_Tail(a, b, x, y)
+
+#define Two_Sum_Tail(a, b, x, y) \
+  bvirt = (REAL) (x - a); \
+  avirt = x - bvirt; \
+  bround = b - bvirt; \
+  around = a - avirt; \
+  y = around + bround
+
+#define Two_Sum(a, b, x, y) \
+  x = (REAL) (a + b); \
+  Two_Sum_Tail(a, b, x, y)
+
+#define Two_Diff_Tail(a, b, x, y) \
+  bvirt = (REAL) (a - x); \
+  avirt = x + bvirt; \
+  bround = bvirt - b; \
+  around = a - avirt; \
+  y = around + bround
+
+#define Two_Diff(a, b, x, y) \
+  x = (REAL) (a - b); \
+  Two_Diff_Tail(a, b, x, y)
+
+#define Split(a, ahi, alo) \
+  c = (REAL) (splitter * a); \
+  abig = (REAL) (c - a); \
+  ahi = c - abig; \
+  alo = a - ahi
+
+#define Two_Product_Tail(a, b, x, y) \
+  Split(a, ahi, alo); \
+  Split(b, bhi, blo); \
+  err1 = x - (ahi * bhi); \
+  err2 = err1 - (alo * bhi); \
+  err3 = err2 - (ahi * blo); \
+  y = (alo * blo) - err3
+
+#define Two_Product(a, b, x, y) \
+  x = (REAL) (a * b); \
+  Two_Product_Tail(a, b, x, y)
+
+/* Two_Product_Presplit() is Two_Product() where one of the inputs has       */
+/*   already been split.  Avoids redundant splitting.                        */
+
+#define Two_Product_Presplit(a, b, bhi, blo, x, y) \
+  x = (REAL) (a * b); \
+  Split(a, ahi, alo); \
+  err1 = x - (ahi * bhi); \
+  err2 = err1 - (alo * bhi); \
+  err3 = err2 - (ahi * blo); \
+  y = (alo * blo) - err3
+
+/* Square() can be done more quickly than Two_Product().                     */
+
+#define Square_Tail(a, x, y) \
+  Split(a, ahi, alo); \
+  err1 = x - (ahi * ahi); \
+  err3 = err1 - ((ahi + ahi) * alo); \
+  y = (alo * alo) - err3
+
+#define Square(a, x, y) \
+  x = (REAL) (a * a); \
+  Square_Tail(a, x, y)
+
+/* Macros for summing expansions of various fixed lengths.  These are all    */
+/*   unrolled versions of Expansion_Sum().                                   */
+
+#define Two_One_Sum(a1, a0, b, x2, x1, x0) \
+  Two_Sum(a0, b , _i, x0); \
+  Two_Sum(a1, _i, x2, x1)
+
+#define Two_One_Diff(a1, a0, b, x2, x1, x0) \
+  Two_Diff(a0, b , _i, x0); \
+  Two_Sum( a1, _i, x2, x1)
+
+#define Two_Two_Sum(a1, a0, b1, b0, x3, x2, x1, x0) \
+  Two_One_Sum(a1, a0, b0, _j, _0, x0); \
+  Two_One_Sum(_j, _0, b1, x3, x2, x1)
+
+#define Two_Two_Diff(a1, a0, b1, b0, x3, x2, x1, x0) \
+  Two_One_Diff(a1, a0, b0, _j, _0, x0); \
+  Two_One_Diff(_j, _0, b1, x3, x2, x1)
+
+/*****************************************************************************/
+/*                                                                           */
+/*  exactinit()   Initialize the variables used for exact arithmetic.        */
+/*                                                                           */
+/*  `epsilon' is the largest power of two such that 1.0 + epsilon = 1.0 in   */
+/*  floating-point arithmetic.  `epsilon' bounds the relative roundoff       */
+/*  error.  It is used for floating-point error analysis.                    */
+/*                                                                           */
+/*  `splitter' is used to split floating-point numbers into two half-        */
+/*  length significands for exact multiplication.                            */
+/*                                                                           */
+/*  I imagine that a highly optimizing compiler might be too smart for its   */
+/*  own good, and somehow cause this routine to fail, if it pretends that    */
+/*  floating-point arithmetic is too much like real arithmetic.              */
+/*                                                                           */
+/*  Don't change this routine unless you fully understand it.                */
+/*                                                                           */
+/*****************************************************************************/
+
+void exactinit()
+{
+  REAL half;
+  REAL check, lastcheck;
+  int every_other;
+
+  every_other = 1;
+  half = 0.5;
+  epsilon = 1.0;
+  splitter = 1.0;
+  check = 1.0;
+  /* Repeatedly divide `epsilon' by two until it is too small to add to      */
+  /*   one without causing roundoff.  (Also check if the sum is equal to     */
+  /*   the previous sum, for machines that round up instead of using exact   */
+  /*   rounding.  Not that these routines will work on such machines anyway. */
+  do {
+    lastcheck = check;
+    epsilon *= half;
+    if (every_other) {
+      splitter *= 2.0;
+    }
+    every_other = !every_other;
+    check = 1.0 + epsilon;
+  } while ((check != 1.0) && (check != lastcheck));
+  splitter += 1.0;
+  if (verbose > 1) {
+    printf("Floating point roundoff is of magnitude %.17g\n", epsilon);
+    printf("Floating point splitter is %.17g\n", splitter);
+  }
+  /* Error bounds for orientation and incircle tests. */
+  resulterrbound = (3.0 + 8.0 * epsilon) * epsilon;
+  ccwerrboundA = (3.0 + 16.0 * epsilon) * epsilon;
+  ccwerrboundB = (2.0 + 12.0 * epsilon) * epsilon;
+  ccwerrboundC = (9.0 + 64.0 * epsilon) * epsilon * epsilon;
+  iccerrboundA = (10.0 + 96.0 * epsilon) * epsilon;
+  iccerrboundB = (4.0 + 48.0 * epsilon) * epsilon;
+  iccerrboundC = (44.0 + 576.0 * epsilon) * epsilon * epsilon;
+}
+
+/*****************************************************************************/
+/*                                                                           */
+/*  fast_expansion_sum_zeroelim()   Sum two expansions, eliminating zero     */
+/*                                  components from the output expansion.    */
+/*                                                                           */
+/*  Sets h = e + f.  See my Robust Predicates paper for details.             */
+/*                                                                           */
+/*  If round-to-even is used (as with IEEE 754), maintains the strongly      */
+/*  nonoverlapping property.  (That is, if e is strongly nonoverlapping, h   */
+/*  will be also.)  Does NOT maintain the nonoverlapping or nonadjacent      */
+/*  properties.                                                              */
+/*                                                                           */
+/*****************************************************************************/
+
+int fast_expansion_sum_zeroelim(elen, e, flen, f, h)  /* h cannot be e or f. */
+int elen;
+REAL *e;
+int flen;
+REAL *f;
+REAL *h;
+{
+  REAL Q;
+  INEXACT REAL Qnew;
+  INEXACT REAL hh;
+  INEXACT REAL bvirt;
+  REAL avirt, bround, around;
+  int eindex, findex, hindex;
+  REAL enow, fnow;
+
+  enow = e[0];
+  fnow = f[0];
+  eindex = findex = 0;
+  if ((fnow > enow) == (fnow > -enow)) {
+    Q = enow;
+    enow = e[++eindex];
+  } else {
+    Q = fnow;
+    fnow = f[++findex];
+  }
+  hindex = 0;
+  if ((eindex < elen) && (findex < flen)) {
+    if ((fnow > enow) == (fnow > -enow)) {
+      Fast_Two_Sum(enow, Q, Qnew, hh);
+      enow = e[++eindex];
+    } else {
+      Fast_Two_Sum(fnow, Q, Qnew, hh);
+      fnow = f[++findex];
+    }
+    Q = Qnew;
+    if (hh != 0.0) {
+      h[hindex++] = hh;
+    }
+    while ((eindex < elen) && (findex < flen)) {
+      if ((fnow > enow) == (fnow > -enow)) {
+        Two_Sum(Q, enow, Qnew, hh);
+        enow = e[++eindex];
+      } else {
+        Two_Sum(Q, fnow, Qnew, hh);
+        fnow = f[++findex];
+      }
+      Q = Qnew;
+      if (hh != 0.0) {
+        h[hindex++] = hh;
+      }
+    }
+  }
+  while (eindex < elen) {
+    Two_Sum(Q, enow, Qnew, hh);
+    enow = e[++eindex];
+    Q = Qnew;
+    if (hh != 0.0) {
+      h[hindex++] = hh;
+    }
+  }
+  while (findex < flen) {
+    Two_Sum(Q, fnow, Qnew, hh);
+    fnow = f[++findex];
+    Q = Qnew;
+    if (hh != 0.0) {
+      h[hindex++] = hh;
+    }
+  }
+  if ((Q != 0.0) || (hindex == 0)) {
+    h[hindex++] = Q;
+  }
+  return hindex;
+}
+
+/*****************************************************************************/
+/*                                                                           */
+/*  scale_expansion_zeroelim()   Multiply an expansion by a scalar,          */
+/*                               eliminating zero components from the        */
+/*                               output expansion.                           */
+/*                                                                           */
+/*  Sets h = be.  See my Robust Predicates paper for details.                */
+/*                                                                           */
+/*  Maintains the nonoverlapping property.  If round-to-even is used (as     */
+/*  with IEEE 754), maintains the strongly nonoverlapping and nonadjacent    */
+/*  properties as well.  (That is, if e has one of these properties, so      */
+/*  will h.)                                                                 */
+/*                                                                           */
+/*****************************************************************************/
+
+int scale_expansion_zeroelim(elen, e, b, h)   /* e and h cannot be the same. */
+int elen;
+REAL *e;
+REAL b;
+REAL *h;
+{
+  INEXACT REAL Q, sum;
+  REAL hh;
+  INEXACT REAL product1;
+  REAL product0;
+  int eindex, hindex;
+  REAL enow;
+  INEXACT REAL bvirt;
+  REAL avirt, bround, around;
+  INEXACT REAL c;
+  INEXACT REAL abig;
+  REAL ahi, alo, bhi, blo;
+  REAL err1, err2, err3;
+
+  Split(b, bhi, blo);
+  Two_Product_Presplit(e[0], b, bhi, blo, Q, hh);
+  hindex = 0;
+  if (hh != 0) {
+    h[hindex++] = hh;
+  }
+  for (eindex = 1; eindex < elen; eindex++) {
+    enow = e[eindex];
+    Two_Product_Presplit(enow, b, bhi, blo, product1, product0);
+    Two_Sum(Q, product0, sum, hh);
+    if (hh != 0) {
+      h[hindex++] = hh;
+    }
+    Fast_Two_Sum(product1, sum, Q, hh);
+    if (hh != 0) {
+      h[hindex++] = hh;
+    }
+  }
+  if ((Q != 0.0) || (hindex == 0)) {
+    h[hindex++] = Q;
+  }
+  return hindex;
+}
+
+/*****************************************************************************/
+/*                                                                           */
+/*  estimate()   Produce a one-word estimate of an expansion's value.        */
+/*                                                                           */
+/*  See my Robust Predicates paper for details.                              */
+/*                                                                           */
+/*****************************************************************************/
+
+REAL estimate(elen, e)
+int elen;
+REAL *e;
+{
+  REAL Q;
+  int eindex;
+
+  Q = e[0];
+  for (eindex = 1; eindex < elen; eindex++) {
+    Q += e[eindex];
+  }
+  return Q;
+}
+
+/*****************************************************************************/
+/*                                                                           */
+/*  counterclockwise()   Return a positive value if the points pa, pb, and   */
+/*                       pc occur in counterclockwise order; a negative      */
+/*                       value if they occur in clockwise order; and zero    */
+/*                       if they are collinear.  The result is also a rough  */
+/*                       approximation of twice the signed area of the       */
+/*                       triangle defined by the three points.               */
+/*                                                                           */
+/*  Uses exact arithmetic if necessary to ensure a correct answer.  The      */
+/*  result returned is the determinant of a matrix.  This determinant is     */
+/*  computed adaptively, in the sense that exact arithmetic is used only to  */
+/*  the degree it is needed to ensure that the returned value has the        */
+/*  correct sign.  Hence, this function is usually quite fast, but will run  */
+/*  more slowly when the input points are collinear or nearly so.            */
+/*                                                                           */
+/*  See my Robust Predicates paper for details.                              */
+/*                                                                           */
+/*****************************************************************************/
+
+REAL counterclockwiseadapt(pa, pb, pc, detsum)
+point pa;
+point pb;
+point pc;
+REAL detsum;
+{
+  INEXACT REAL acx, acy, bcx, bcy;
+  REAL acxtail, acytail, bcxtail, bcytail;
+  INEXACT REAL detleft, detright;
+  REAL detlefttail, detrighttail;
+  REAL det, errbound;
+  REAL B[4], C1[8], C2[12], D[16];
+  INEXACT REAL B3;
+  int C1length, C2length, Dlength;
+  REAL u[4];
+  INEXACT REAL u3;
+  INEXACT REAL s1, t1;
+  REAL s0, t0;
+
+  INEXACT REAL bvirt;
+  REAL avirt, bround, around;
+  INEXACT REAL c;
+  INEXACT REAL abig;
+  REAL ahi, alo, bhi, blo;
+  REAL err1, err2, err3;
+  INEXACT REAL _i, _j;
+  REAL _0;
+
+  acx = (REAL) (pa[0] - pc[0]);
+  bcx = (REAL) (pb[0] - pc[0]);
+  acy = (REAL) (pa[1] - pc[1]);
+  bcy = (REAL) (pb[1] - pc[1]);
+
+  Two_Product(acx, bcy, detleft, detlefttail);
+  Two_Product(acy, bcx, detright, detrighttail);
+
+  Two_Two_Diff(detleft, detlefttail, detright, detrighttail,
+               B3, B[2], B[1], B[0]);
+  B[3] = B3;
+
+  det = estimate(4, B);
+  errbound = ccwerrboundB * detsum;
+  if ((det >= errbound) || (-det >= errbound)) {
+    return det;
+  }
+
+  Two_Diff_Tail(pa[0], pc[0], acx, acxtail);
+  Two_Diff_Tail(pb[0], pc[0], bcx, bcxtail);
+  Two_Diff_Tail(pa[1], pc[1], acy, acytail);
+  Two_Diff_Tail(pb[1], pc[1], bcy, bcytail);
+
+  if ((acxtail == 0.0) && (acytail == 0.0)
+      && (bcxtail == 0.0) && (bcytail == 0.0)) {
+    return det;
+  }
+
+  errbound = ccwerrboundC * detsum + resulterrbound * Absolute(det);
+  det += (acx * bcytail + bcy * acxtail)
+       - (acy * bcxtail + bcx * acytail);
+  if ((det >= errbound) || (-det >= errbound)) {
+    return det;
+  }
+
+  Two_Product(acxtail, bcy, s1, s0);
+  Two_Product(acytail, bcx, t1, t0);
+  Two_Two_Diff(s1, s0, t1, t0, u3, u[2], u[1], u[0]);
+  u[3] = u3;
+  C1length = fast_expansion_sum_zeroelim(4, B, 4, u, C1);
+
+  Two_Product(acx, bcytail, s1, s0);
+  Two_Product(acy, bcxtail, t1, t0);
+  Two_Two_Diff(s1, s0, t1, t0, u3, u[2], u[1], u[0]);
+  u[3] = u3;
+  C2length = fast_expansion_sum_zeroelim(C1length, C1, 4, u, C2);
+
+  Two_Product(acxtail, bcytail, s1, s0);
+  Two_Product(acytail, bcxtail, t1, t0);
+  Two_Two_Diff(s1, s0, t1, t0, u3, u[2], u[1], u[0]);
+  u[3] = u3;
+  Dlength = fast_expansion_sum_zeroelim(C2length, C2, 4, u, D);
+
+  return(D[Dlength - 1]);
+}
+
+REAL counterclockwise(pa, pb, pc)
+point pa;
+point pb;
+point pc;
+{
+  REAL detleft, detright, det;
+  REAL detsum, errbound;
+
+  counterclockcount++;
+
+  detleft = (pa[0] - pc[0]) * (pb[1] - pc[1]);
+  detright = (pa[1] - pc[1]) * (pb[0] - pc[0]);
+  det = detleft - detright;
+
+  if (noexact) {
+    return det;
+  }
+
+  if (detleft > 0.0) {
+    if (detright <= 0.0) {
+      return det;
+    } else {
+      detsum = detleft + detright;
+    }
+  } else if (detleft < 0.0) {
+    if (detright >= 0.0) {
+      return det;
+    } else {
+      detsum = -detleft - detright;
+    }
+  } else {
+    return det;
+  }
+
+  errbound = ccwerrboundA * detsum;
+  if ((det >= errbound) || (-det >= errbound)) {
+    return det;
+  }
+
+  return counterclockwiseadapt(pa, pb, pc, detsum);
+}
+
+/*****************************************************************************/
+/*                                                                           */
+/*  incircle()   Return a positive value if the point pd lies inside the     */
+/*               circle passing through pa, pb, and pc; a negative value if  */
+/*               it lies outside; and zero if the four points are cocircular.*/
+/*               The points pa, pb, and pc must be in counterclockwise       */
+/*               order, or the sign of the result will be reversed.          */
+/*                                                                           */
+/*  Uses exact arithmetic if necessary to ensure a correct answer.  The      */
+/*  result returned is the determinant of a matrix.  This determinant is     */
+/*  computed adaptively, in the sense that exact arithmetic is used only to  */
+/*  the degree it is needed to ensure that the returned value has the        */
+/*  correct sign.  Hence, this function is usually quite fast, but will run  */
+/*  more slowly when the input points are cocircular or nearly so.           */
+/*                                                                           */
+/*  See my Robust Predicates paper for details.                              */
+/*                                                                           */
+/*****************************************************************************/
+
+REAL incircleadapt(pa, pb, pc, pd, permanent)
+point pa;
+point pb;
+point pc;
+point pd;
+REAL permanent;
+{
+  INEXACT REAL adx, bdx, cdx, ady, bdy, cdy;
+  REAL det, errbound;
+
+  INEXACT REAL bdxcdy1, cdxbdy1, cdxady1, adxcdy1, adxbdy1, bdxady1;
+  REAL bdxcdy0, cdxbdy0, cdxady0, adxcdy0, adxbdy0, bdxady0;
+  REAL bc[4], ca[4], ab[4];
+  INEXACT REAL bc3, ca3, ab3;
+  REAL axbc[8], axxbc[16], aybc[8], ayybc[16], adet[32];
+  int axbclen, axxbclen, aybclen, ayybclen, alen;
+  REAL bxca[8], bxxca[16], byca[8], byyca[16], bdet[32];
+  int bxcalen, bxxcalen, bycalen, byycalen, blen;
+  REAL cxab[8], cxxab[16], cyab[8], cyyab[16], cdet[32];
+  int cxablen, cxxablen, cyablen, cyyablen, clen;
+  REAL abdet[64];
+  int ablen;
+  REAL fin1[1152], fin2[1152];
+  REAL *finnow, *finother, *finswap;
+  int finlength;
+
+  REAL adxtail, bdxtail, cdxtail, adytail, bdytail, cdytail;
+  INEXACT REAL adxadx1, adyady1, bdxbdx1, bdybdy1, cdxcdx1, cdycdy1;
+  REAL adxadx0, adyady0, bdxbdx0, bdybdy0, cdxcdx0, cdycdy0;
+  REAL aa[4], bb[4], cc[4];
+  INEXACT REAL aa3, bb3, cc3;
+  INEXACT REAL ti1, tj1;
+  REAL ti0, tj0;
+  REAL u[4], v[4];
+  INEXACT REAL u3, v3;
+  REAL temp8[8], temp16a[16], temp16b[16], temp16c[16];
+  REAL temp32a[32], temp32b[32], temp48[48], temp64[64];
+  int temp8len, temp16alen, temp16blen, temp16clen;
+  int temp32alen, temp32blen, temp48len, temp64len;
+  REAL axtbb[8], axtcc[8], aytbb[8], aytcc[8];
+  int axtbblen, axtcclen, aytbblen, aytcclen;
+  REAL bxtaa[8], bxtcc[8], bytaa[8], bytcc[8];
+  int bxtaalen, bxtcclen, bytaalen, bytcclen;
+  REAL cxtaa[8], cxtbb[8], cytaa[8], cytbb[8];
+  int cxtaalen, cxtbblen, cytaalen, cytbblen;
+  REAL axtbc[8], aytbc[8], bxtca[8], bytca[8], cxtab[8], cytab[8];
+  int axtbclen, aytbclen, bxtcalen, bytcalen, cxtablen, cytablen;
+  REAL axtbct[16], aytbct[16], bxtcat[16], bytcat[16], cxtabt[16], cytabt[16];
+  int axtbctlen, aytbctlen, bxtcatlen, bytcatlen, cxtabtlen, cytabtlen;
+  REAL axtbctt[8], aytbctt[8], bxtcatt[8];
+  REAL bytcatt[8], cxtabtt[8], cytabtt[8];
+  int axtbcttlen, aytbcttlen, bxtcattlen, bytcattlen, cxtabttlen, cytabttlen;
+  REAL abt[8], bct[8], cat[8];
+  int abtlen, bctlen, catlen;
+  REAL abtt[4], bctt[4], catt[4];
+  int abttlen, bcttlen, cattlen;
+  INEXACT REAL abtt3, bctt3, catt3;
+  REAL negate;
+
+  INEXACT REAL bvirt;
+  REAL avirt, bround, around;
+  INEXACT REAL c;
+  INEXACT REAL abig;
+  REAL ahi, alo, bhi, blo;
+  REAL err1, err2, err3;
+  INEXACT REAL _i, _j;
+  REAL _0;
+
+  adx = (REAL) (pa[0] - pd[0]);
+  bdx = (REAL) (pb[0] - pd[0]);
+  cdx = (REAL) (pc[0] - pd[0]);
+  ady = (REAL) (pa[1] - pd[1]);
+  bdy = (REAL) (pb[1] - pd[1]);
+  cdy = (REAL) (pc[1] - pd[1]);
+
+  Two_Product(bdx, cdy, bdxcdy1, bdxcdy0);
+  Two_Product(cdx, bdy, cdxbdy1, cdxbdy0);
+  Two_Two_Diff(bdxcdy1, bdxcdy0, cdxbdy1, cdxbdy0, bc3, bc[2], bc[1], bc[0]);
+  bc[3] = bc3;
+  axbclen = scale_expansion_zeroelim(4, bc, adx, axbc);
+  axxbclen = scale_expansion_zeroelim(axbclen, axbc, adx, axxbc);
+  aybclen = scale_expansion_zeroelim(4, bc, ady, aybc);
+  ayybclen = scale_expansion_zeroelim(aybclen, aybc, ady, ayybc);
+  alen = fast_expansion_sum_zeroelim(axxbclen, axxbc, ayybclen, ayybc, adet);
+
+  Two_Product(cdx, ady, cdxady1, cdxady0);
+  Two_Product(adx, cdy, adxcdy1, adxcdy0);
+  Two_Two_Diff(cdxady1, cdxady0, adxcdy1, adxcdy0, ca3, ca[2], ca[1], ca[0]);
+  ca[3] = ca3;
+  bxcalen = scale_expansion_zeroelim(4, ca, bdx, bxca);
+  bxxcalen = scale_expansion_zeroelim(bxcalen, bxca, bdx, bxxca);
+  bycalen = scale_expansion_zeroelim(4, ca, bdy, byca);
+  byycalen = scale_expansion_zeroelim(bycalen, byca, bdy, byyca);
+  blen = fast_expansion_sum_zeroelim(bxxcalen, bxxca, byycalen, byyca, bdet);
+
+  Two_Product(adx, bdy, adxbdy1, adxbdy0);
+  Two_Product(bdx, ady, bdxady1, bdxady0);
+  Two_Two_Diff(adxbdy1, adxbdy0, bdxady1, bdxady0, ab3, ab[2], ab[1], ab[0]);
+  ab[3] = ab3;
+  cxablen = scale_expansion_zeroelim(4, ab, cdx, cxab);
+  cxxablen = scale_expansion_zeroelim(cxablen, cxab, cdx, cxxab);
+  cyablen = scale_expansion_zeroelim(4, ab, cdy, cyab);
+  cyyablen = scale_expansion_zeroelim(cyablen, cyab, cdy, cyyab);
+  clen = fast_expansion_sum_zeroelim(cxxablen, cxxab, cyyablen, cyyab, cdet);
+
+  ablen = fast_expansion_sum_zeroelim(alen, adet, blen, bdet, abdet);
+  finlength = fast_expansion_sum_zeroelim(ablen, abdet, clen, cdet, fin1);
+
+  det = estimate(finlength, fin1);
+  errbound = iccerrboundB * permanent;
+  if ((det >= errbound) || (-det >= errbound)) {
+    return det;
+  }
+
+  Two_Diff_Tail(pa[0], pd[0], adx, adxtail);
+  Two_Diff_Tail(pa[1], pd[1], ady, adytail);
+  Two_Diff_Tail(pb[0], pd[0], bdx, bdxtail);
+  Two_Diff_Tail(pb[1], pd[1], bdy, bdytail);
+  Two_Diff_Tail(pc[0], pd[0], cdx, cdxtail);
+  Two_Diff_Tail(pc[1], pd[1], cdy, cdytail);
+  if ((adxtail == 0.0) && (bdxtail == 0.0) && (cdxtail == 0.0)
+      && (adytail == 0.0) && (bdytail == 0.0) && (cdytail == 0.0)) {
+    return det;
+  }
+
+  errbound = iccerrboundC * permanent + resulterrbound * Absolute(det);
+  det += ((adx * adx + ady * ady) * ((bdx * cdytail + cdy * bdxtail)
+                                     - (bdy * cdxtail + cdx * bdytail))
+          + 2.0 * (adx * adxtail + ady * adytail) * (bdx * cdy - bdy * cdx))
+       + ((bdx * bdx + bdy * bdy) * ((cdx * adytail + ady * cdxtail)
+                                     - (cdy * adxtail + adx * cdytail))
+          + 2.0 * (bdx * bdxtail + bdy * bdytail) * (cdx * ady - cdy * adx))
+       + ((cdx * cdx + cdy * cdy) * ((adx * bdytail + bdy * adxtail)
+                                     - (ady * bdxtail + bdx * adytail))
+          + 2.0 * (cdx * cdxtail + cdy * cdytail) * (adx * bdy - ady * bdx));
+  if ((det >= errbound) || (-det >= errbound)) {
+    return det;
+  }
+
+  finnow = fin1;
+  finother = fin2;
+
+  if ((bdxtail != 0.0) || (bdytail != 0.0)
+      || (cdxtail != 0.0) || (cdytail != 0.0)) {
+    Square(adx, adxadx1, adxadx0);
+    Square(ady, adyady1, adyady0);
+    Two_Two_Sum(adxadx1, adxadx0, adyady1, adyady0, aa3, aa[2], aa[1], aa[0]);
+    aa[3] = aa3;
+  }
+  if ((cdxtail != 0.0) || (cdytail != 0.0)
+      || (adxtail != 0.0) || (adytail != 0.0)) {
+    Square(bdx, bdxbdx1, bdxbdx0);
+    Square(bdy, bdybdy1, bdybdy0);
+    Two_Two_Sum(bdxbdx1, bdxbdx0, bdybdy1, bdybdy0, bb3, bb[2], bb[1], bb[0]);
+    bb[3] = bb3;
+  }
+  if ((adxtail != 0.0) || (adytail != 0.0)
+      || (bdxtail != 0.0) || (bdytail != 0.0)) {
+    Square(cdx, cdxcdx1, cdxcdx0);
+    Square(cdy, cdycdy1, cdycdy0);
+    Two_Two_Sum(cdxcdx1, cdxcdx0, cdycdy1, cdycdy0, cc3, cc[2], cc[1], cc[0]);
+    cc[3] = cc3;
+  }
+
+  if (adxtail != 0.0) {
+    axtbclen = scale_expansion_zeroelim(4, bc, adxtail, axtbc);
+    temp16alen = scale_expansion_zeroelim(axtbclen, axtbc, 2.0 * adx,
+                                          temp16a);
+
+    axtcclen = scale_expansion_zeroelim(4, cc, adxtail, axtcc);
+    temp16blen = scale_expansion_zeroelim(axtcclen, axtcc, bdy, temp16b);
+
+    axtbblen = scale_expansion_zeroelim(4, bb, adxtail, axtbb);
+    temp16clen = scale_expansion_zeroelim(axtbblen, axtbb, -cdy, temp16c);
+
+    temp32alen = fast_expansion_sum_zeroelim(temp16alen, temp16a,
+                                            temp16blen, temp16b, temp32a);
+    temp48len = fast_expansion_sum_zeroelim(temp16clen, temp16c,
+                                            temp32alen, temp32a, temp48);
+    finlength = fast_expansion_sum_zeroelim(finlength, finnow, temp48len,
+                                            temp48, finother);
+    finswap = finnow; finnow = finother; finother = finswap;
+  }
+  if (adytail != 0.0) {
+    aytbclen = scale_expansion_zeroelim(4, bc, adytail, aytbc);
+    temp16alen = scale_expansion_zeroelim(aytbclen, aytbc, 2.0 * ady,
+                                          temp16a);
+
+    aytbblen = scale_expansion_zeroelim(4, bb, adytail, aytbb);
+    temp16blen = scale_expansion_zeroelim(aytbblen, aytbb, cdx, temp16b);
+
+    aytcclen = scale_expansion_zeroelim(4, cc, adytail, aytcc);
+    temp16clen = scale_expansion_zeroelim(aytcclen, aytcc, -bdx, temp16c);
+
+    temp32alen = fast_expansion_sum_zeroelim(temp16alen, temp16a,
+                                            temp16blen, temp16b, temp32a);
+    temp48len = fast_expansion_sum_zeroelim(temp16clen, temp16c,
+                                            temp32alen, temp32a, temp48);
+    finlength = fast_expansion_sum_zeroelim(finlength, finnow, temp48len,
+                                            temp48, finother);
+    finswap = finnow; finnow = finother; finother = finswap;
+  }
+  if (bdxtail != 0.0) {
+    bxtcalen = scale_expansion_zeroelim(4, ca, bdxtail, bxtca);
+    temp16alen = scale_expansion_zeroelim(bxtcalen, bxtca, 2.0 * bdx,
+                                          temp16a);
+
+    bxtaalen = scale_expansion_zeroelim(4, aa, bdxtail, bxtaa);
+    temp16blen = scale_expansion_zeroelim(bxtaalen, bxtaa, cdy, temp16b);
+
+    bxtcclen = scale_expansion_zeroelim(4, cc, bdxtail, bxtcc);
+    temp16clen = scale_expansion_zeroelim(bxtcclen, bxtcc, -ady, temp16c);
+
+    temp32alen = fast_expansion_sum_zeroelim(temp16alen, temp16a,
+                                            temp16blen, temp16b, temp32a);
+    temp48len = fast_expansion_sum_zeroelim(temp16clen, temp16c,
+                                            temp32alen, temp32a, temp48);
+    finlength = fast_expansion_sum_zeroelim(finlength, finnow, temp48len,
+                                            temp48, finother);
+    finswap = finnow; finnow = finother; finother = finswap;
+  }
+  if (bdytail != 0.0) {
+    bytcalen = scale_expansion_zeroelim(4, ca, bdytail, bytca);
+    temp16alen = scale_expansion_zeroelim(bytcalen, bytca, 2.0 * bdy,
+                                          temp16a);
+
+    bytcclen = scale_expansion_zeroelim(4, cc, bdytail, bytcc);
+    temp16blen = scale_expansion_zeroelim(bytcclen, bytcc, adx, temp16b);
+
+    bytaalen = scale_expansion_zeroelim(4, aa, bdytail, bytaa);
+    temp16clen = scale_expansion_zeroelim(bytaalen, bytaa, -cdx, temp16c);
+
+    temp32alen = fast_expansion_sum_zeroelim(temp16alen, temp16a,
+                                            temp16blen, temp16b, temp32a);
+    temp48len = fast_expansion_sum_zeroelim(temp16clen, temp16c,
+                                            temp32alen, temp32a, temp48);
+    finlength = fast_expansion_sum_zeroelim(finlength, finnow, temp48len,
+                                            temp48, finother);
+    finswap = finnow; finnow = finother; finother = finswap;
+  }
+  if (cdxtail != 0.0) {
+    cxtablen = scale_expansion_zeroelim(4, ab, cdxtail, cxtab);
+    temp16alen = scale_expansion_zeroelim(cxtablen, cxtab, 2.0 * cdx,
+                                          temp16a);
+
+    cxtbblen = scale_expansion_zeroelim(4, bb, cdxtail, cxtbb);
+    temp16blen = scale_expansion_zeroelim(cxtbblen, cxtbb, ady, temp16b);
+
+    cxtaalen = scale_expansion_zeroelim(4, aa, cdxtail, cxtaa);
+    temp16clen = scale_expansion_zeroelim(cxtaalen, cxtaa, -bdy, temp16c);
+
+    temp32alen = fast_expansion_sum_zeroelim(temp16alen, temp16a,
+                                            temp16blen, temp16b, temp32a);
+    temp48len = fast_expansion_sum_zeroelim(temp16clen, temp16c,
+                                            temp32alen, temp32a, temp48);
+    finlength = fast_expansion_sum_zeroelim(finlength, finnow, temp48len,
+                                            temp48, finother);
+    finswap = finnow; finnow = finother; finother = finswap;
+  }
+  if (cdytail != 0.0) {
+    cytablen = scale_expansion_zeroelim(4, ab, cdytail, cytab);
+    temp16alen = scale_expansion_zeroelim(cytablen, cytab, 2.0 * cdy,
+                                          temp16a);
+
+    cytaalen = scale_expansion_zeroelim(4, aa, cdytail, cytaa);
+    temp16blen = scale_expansion_zeroelim(cytaalen, cytaa, bdx, temp16b);
+
+    cytbblen = scale_expansion_zeroelim(4, bb, cdytail, cytbb);
+    temp16clen = scale_expansion_zeroelim(cytbblen, cytbb, -adx, temp16c);
+
+    temp32alen = fast_expansion_sum_zeroelim(temp16alen, temp16a,
+                                            temp16blen, temp16b, temp32a);
+    temp48len = fast_expansion_sum_zeroelim(temp16clen, temp16c,
+                                            temp32alen, temp32a, temp48);
+    finlength = fast_expansion_sum_zeroelim(finlength, finnow, temp48len,
+                                            temp48, finother);
+    finswap = finnow; finnow = finother; finother = finswap;
+  }
+
+  if ((adxtail != 0.0) || (adytail != 0.0)) {
+    if ((bdxtail != 0.0) || (bdytail != 0.0)
+        || (cdxtail != 0.0) || (cdytail != 0.0)) {
+      Two_Product(bdxtail, cdy, ti1, ti0);
+      Two_Product(bdx, cdytail, tj1, tj0);
+      Two_Two_Sum(ti1, ti0, tj1, tj0, u3, u[2], u[1], u[0]);
+      u[3] = u3;
+      negate = -bdy;
+      Two_Product(cdxtail, negate, ti1, ti0);
+      negate = -bdytail;
+      Two_Product(cdx, negate, tj1, tj0);
+      Two_Two_Sum(ti1, ti0, tj1, tj0, v3, v[2], v[1], v[0]);
+      v[3] = v3;
+      bctlen = fast_expansion_sum_zeroelim(4, u, 4, v, bct);
+
+      Two_Product(bdxtail, cdytail, ti1, ti0);
+      Two_Product(cdxtail, bdytail, tj1, tj0);
+      Two_Two_Diff(ti1, ti0, tj1, tj0, bctt3, bctt[2], bctt[1], bctt[0]);
+      bctt[3] = bctt3;
+      bcttlen = 4;
+    } else {
+      bct[0] = 0.0;
+      bctlen = 1;
+      bctt[0] = 0.0;
+      bcttlen = 1;
+    }
+
+    if (adxtail != 0.0) {
+      temp16alen = scale_expansion_zeroelim(axtbclen, axtbc, adxtail, temp16a);
+      axtbctlen = scale_expansion_zeroelim(bctlen, bct, adxtail, axtbct);
+      temp32alen = scale_expansion_zeroelim(axtbctlen, axtbct, 2.0 * adx,
+                                            temp32a);
+      temp48len = fast_expansion_sum_zeroelim(temp16alen, temp16a,
+                                              temp32alen, temp32a, temp48);
+      finlength = fast_expansion_sum_zeroelim(finlength, finnow, temp48len,
+                                              temp48, finother);
+      finswap = finnow; finnow = finother; finother = finswap;
+      if (bdytail != 0.0) {
+        temp8len = scale_expansion_zeroelim(4, cc, adxtail, temp8);
+        temp16alen = scale_expansion_zeroelim(temp8len, temp8, bdytail,
+                                              temp16a);
+        finlength = fast_expansion_sum_zeroelim(finlength, finnow, temp16alen,
+                                                temp16a, finother);
+        finswap = finnow; finnow = finother; finother = finswap;
+      }
+      if (cdytail != 0.0) {
+        temp8len = scale_expansion_zeroelim(4, bb, -adxtail, temp8);
+        temp16alen = scale_expansion_zeroelim(temp8len, temp8, cdytail,
+                                              temp16a);
+        finlength = fast_expansion_sum_zeroelim(finlength, finnow, temp16alen,
+                                                temp16a, finother);
+        finswap = finnow; finnow = finother; finother = finswap;
+      }
+
+      temp32alen = scale_expansion_zeroelim(axtbctlen, axtbct, adxtail,
+                                            temp32a);
+      axtbcttlen = scale_expansion_zeroelim(bcttlen, bctt, adxtail, axtbctt);
+      temp16alen = scale_expansion_zeroelim(axtbcttlen, axtbctt, 2.0 * adx,
+                                            temp16a);
+      temp16blen = scale_expansion_zeroelim(axtbcttlen, axtbctt, adxtail,
+                                            temp16b);
+      temp32blen = fast_expansion_sum_zeroelim(temp16alen, temp16a,
+                                              temp16blen, temp16b, temp32b);
+      temp64len = fast_expansion_sum_zeroelim(temp32alen, temp32a,
+                                              temp32blen, temp32b, temp64);
+      finlength = fast_expansion_sum_zeroelim(finlength, finnow, temp64len,
+                                              temp64, finother);
+      finswap = finnow; finnow = finother; finother = finswap;
+    }
+    if (adytail != 0.0) {
+      temp16alen = scale_expansion_zeroelim(aytbclen, aytbc, adytail, temp16a);
+      aytbctlen = scale_expansion_zeroelim(bctlen, bct, adytail, aytbct);
+      temp32alen = scale_expansion_zeroelim(aytbctlen, aytbct, 2.0 * ady,
+                                            temp32a);
+      temp48len = fast_expansion_sum_zeroelim(temp16alen, temp16a,
+                                              temp32alen, temp32a, temp48);
+      finlength = fast_expansion_sum_zeroelim(finlength, finnow, temp48len,
+                                              temp48, finother);
+      finswap = finnow; finnow = finother; finother = finswap;
+
+
+      temp32alen = scale_expansion_zeroelim(aytbctlen, aytbct, adytail,
+                                            temp32a);
+      aytbcttlen = scale_expansion_zeroelim(bcttlen, bctt, adytail, aytbctt);
+      temp16alen = scale_expansion_zeroelim(aytbcttlen, aytbctt, 2.0 * ady,
+                                            temp16a);
+      temp16blen = scale_expansion_zeroelim(aytbcttlen, aytbctt, adytail,
+                                            temp16b);
+      temp32blen = fast_expansion_sum_zeroelim(temp16alen, temp16a,
+                                              temp16blen, temp16b, temp32b);
+      temp64len = fast_expansion_sum_zeroelim(temp32alen, temp32a,
+                                              temp32blen, temp32b, temp64);
+      finlength = fast_expansion_sum_zeroelim(finlength, finnow, temp64len,
+                                              temp64, finother);
+      finswap = finnow; finnow = finother; finother = finswap;
+    }
+  }
+  if ((bdxtail != 0.0) || (bdytail != 0.0)) {
+    if ((cdxtail != 0.0) || (cdytail != 0.0)
+        || (adxtail != 0.0) || (adytail != 0.0)) {
+      Two_Product(cdxtail, ady, ti1, ti0);
+      Two_Product(cdx, adytail, tj1, tj0);
+      Two_Two_Sum(ti1, ti0, tj1, tj0, u3, u[2], u[1], u[0]);
+      u[3] = u3;
+      negate = -cdy;
+      Two_Product(adxtail, negate, ti1, ti0);
+      negate = -cdytail;
+      Two_Product(adx, negate, tj1, tj0);
+      Two_Two_Sum(ti1, ti0, tj1, tj0, v3, v[2], v[1], v[0]);
+      v[3] = v3;
+      catlen = fast_expansion_sum_zeroelim(4, u, 4, v, cat);
+
+      Two_Product(cdxtail, adytail, ti1, ti0);
+      Two_Product(adxtail, cdytail, tj1, tj0);
+      Two_Two_Diff(ti1, ti0, tj1, tj0, catt3, catt[2], catt[1], catt[0]);
+      catt[3] = catt3;
+      cattlen = 4;
+    } else {
+      cat[0] = 0.0;
+      catlen = 1;
+      catt[0] = 0.0;
+      cattlen = 1;
+    }
+
+    if (bdxtail != 0.0) {
+      temp16alen = scale_expansion_zeroelim(bxtcalen, bxtca, bdxtail, temp16a);
+      bxtcatlen = scale_expansion_zeroelim(catlen, cat, bdxtail, bxtcat);
+      temp32alen = scale_expansion_zeroelim(bxtcatlen, bxtcat, 2.0 * bdx,
+                                            temp32a);
+      temp48len = fast_expansion_sum_zeroelim(temp16alen, temp16a,
+                                              temp32alen, temp32a, temp48);
+      finlength = fast_expansion_sum_zeroelim(finlength, finnow, temp48len,
+                                              temp48, finother);
+      finswap = finnow; finnow = finother; finother = finswap;
+      if (cdytail != 0.0) {
+        temp8len = scale_expansion_zeroelim(4, aa, bdxtail, temp8);
+        temp16alen = scale_expansion_zeroelim(temp8len, temp8, cdytail,
+                                              temp16a);
+        finlength = fast_expansion_sum_zeroelim(finlength, finnow, temp16alen,
+                                                temp16a, finother);
+        finswap = finnow; finnow = finother; finother = finswap;
+      }
+      if (adytail != 0.0) {
+        temp8len = scale_expansion_zeroelim(4, cc, -bdxtail, temp8);
+        temp16alen = scale_expansion_zeroelim(temp8len, temp8, adytail,
+                                              temp16a);
+        finlength = fast_expansion_sum_zeroelim(finlength, finnow, temp16alen,
+                                                temp16a, finother);
+        finswap = finnow; finnow = finother; finother = finswap;
+      }
+
+      temp32alen = scale_expansion_zeroelim(bxtcatlen, bxtcat, bdxtail,
+                                            temp32a);
+      bxtcattlen = scale_expansion_zeroelim(cattlen, catt, bdxtail, bxtcatt);
+      temp16alen = scale_expansion_zeroelim(bxtcattlen, bxtcatt, 2.0 * bdx,
+                                            temp16a);
+      temp16blen = scale_expansion_zeroelim(bxtcattlen, bxtcatt, bdxtail,
+                                            temp16b);
+      temp32blen = fast_expansion_sum_zeroelim(temp16alen, temp16a,
+                                              temp16blen, temp16b, temp32b);
+      temp64len = fast_expansion_sum_zeroelim(temp32alen, temp32a,
+                                              temp32blen, temp32b, temp64);
+      finlength = fast_expansion_sum_zeroelim(finlength, finnow, temp64len,
+                                              temp64, finother);
+      finswap = finnow; finnow = finother; finother = finswap;
+    }
+    if (bdytail != 0.0) {
+      temp16alen = scale_expansion_zeroelim(bytcalen, bytca, bdytail, temp16a);
+      bytcatlen = scale_expansion_zeroelim(catlen, cat, bdytail, bytcat);
+      temp32alen = scale_expansion_zeroelim(bytcatlen, bytcat, 2.0 * bdy,
+                                            temp32a);
+      temp48len = fast_expansion_sum_zeroelim(temp16alen, temp16a,
+                                              temp32alen, temp32a, temp48);
+      finlength = fast_expansion_sum_zeroelim(finlength, finnow, temp48len,
+                                              temp48, finother);
+      finswap = finnow; finnow = finother; finother = finswap;
+
+
+      temp32alen = scale_expansion_zeroelim(bytcatlen, bytcat, bdytail,
+                                            temp32a);
+      bytcattlen = scale_expansion_zeroelim(cattlen, catt, bdytail, bytcatt);
+      temp16alen = scale_expansion_zeroelim(bytcattlen, bytcatt, 2.0 * bdy,
+                                            temp16a);
+      temp16blen = scale_expansion_zeroelim(bytcattlen, bytcatt, bdytail,
+                                            temp16b);
+      temp32blen = fast_expansion_sum_zeroelim(temp16alen, temp16a,
+                                              temp16blen, temp16b, temp32b);
+      temp64len = fast_expansion_sum_zeroelim(temp32alen, temp32a,
+                                              temp32blen, temp32b, temp64);
+      finlength = fast_expansion_sum_zeroelim(finlength, finnow, temp64len,
+                                              temp64, finother);
+      finswap = finnow; finnow = finother; finother = finswap;
+    }
+  }
+  if ((cdxtail != 0.0) || (cdytail != 0.0)) {
+    if ((adxtail != 0.0) || (adytail != 0.0)
+        || (bdxtail != 0.0) || (bdytail != 0.0)) {
+      Two_Product(adxtail, bdy, ti1, ti0);
+      Two_Product(adx, bdytail, tj1, tj0);
+      Two_Two_Sum(ti1, ti0, tj1, tj0, u3, u[2], u[1], u[0]);
+      u[3] = u3;
+      negate = -ady;
+      Two_Product(bdxtail, negate, ti1, ti0);
+      negate = -adytail;
+      Two_Product(bdx, negate, tj1, tj0);
+      Two_Two_Sum(ti1, ti0, tj1, tj0, v3, v[2], v[1], v[0]);
+      v[3] = v3;
+      abtlen = fast_expansion_sum_zeroelim(4, u, 4, v, abt);
+
+      Two_Product(adxtail, bdytail, ti1, ti0);
+      Two_Product(bdxtail, adytail, tj1, tj0);
+      Two_Two_Diff(ti1, ti0, tj1, tj0, abtt3, abtt[2], abtt[1], abtt[0]);
+      abtt[3] = abtt3;
+      abttlen = 4;
+    } else {
+      abt[0] = 0.0;
+      abtlen = 1;
+      abtt[0] = 0.0;
+      abttlen = 1;
+    }
+
+    if (cdxtail != 0.0) {
+      temp16alen = scale_expansion_zeroelim(cxtablen, cxtab, cdxtail, temp16a);
+      cxtabtlen = scale_expansion_zeroelim(abtlen, abt, cdxtail, cxtabt);
+      temp32alen = scale_expansion_zeroelim(cxtabtlen, cxtabt, 2.0 * cdx,
+                                            temp32a);
+      temp48len = fast_expansion_sum_zeroelim(temp16alen, temp16a,
+                                              temp32alen, temp32a, temp48);
+      finlength = fast_expansion_sum_zeroelim(finlength, finnow, temp48len,
+                                              temp48, finother);
+      finswap = finnow; finnow = finother; finother = finswap;
+      if (adytail != 0.0) {
+        temp8len = scale_expansion_zeroelim(4, bb, cdxtail, temp8);
+        temp16alen = scale_expansion_zeroelim(temp8len, temp8, adytail,
+                                              temp16a);
+        finlength = fast_expansion_sum_zeroelim(finlength, finnow, temp16alen,
+                                                temp16a, finother);
+        finswap = finnow; finnow = finother; finother = finswap;
+      }
+      if (bdytail != 0.0) {
+        temp8len = scale_expansion_zeroelim(4, aa, -cdxtail, temp8);
+        temp16alen = scale_expansion_zeroelim(temp8len, temp8, bdytail,
+                                              temp16a);
+        finlength = fast_expansion_sum_zeroelim(finlength, finnow, temp16alen,
+                                                temp16a, finother);
+        finswap = finnow; finnow = finother; finother = finswap;
+      }
+
+      temp32alen = scale_expansion_zeroelim(cxtabtlen, cxtabt, cdxtail,
+                                            temp32a);
+      cxtabttlen = scale_expansion_zeroelim(abttlen, abtt, cdxtail, cxtabtt);
+      temp16alen = scale_expansion_zeroelim(cxtabttlen, cxtabtt, 2.0 * cdx,
+                                            temp16a);
+      temp16blen = scale_expansion_zeroelim(cxtabttlen, cxtabtt, cdxtail,
+                                            temp16b);
+      temp32blen = fast_expansion_sum_zeroelim(temp16alen, temp16a,
+                                              temp16blen, temp16b, temp32b);
+      temp64len = fast_expansion_sum_zeroelim(temp32alen, temp32a,
+                                              temp32blen, temp32b, temp64);
+      finlength = fast_expansion_sum_zeroelim(finlength, finnow, temp64len,
+                                              temp64, finother);
+      finswap = finnow; finnow = finother; finother = finswap;
+    }
+    if (cdytail != 0.0) {
+      temp16alen = scale_expansion_zeroelim(cytablen, cytab, cdytail, temp16a);
+      cytabtlen = scale_expansion_zeroelim(abtlen, abt, cdytail, cytabt);
+      temp32alen = scale_expansion_zeroelim(cytabtlen, cytabt, 2.0 * cdy,
+                                            temp32a);
+      temp48len = fast_expansion_sum_zeroelim(temp16alen, temp16a,
+                                              temp32alen, temp32a, temp48);
+      finlength = fast_expansion_sum_zeroelim(finlength, finnow, temp48len,
+                                              temp48, finother);
+      finswap = finnow; finnow = finother; finother = finswap;
+
+
+      temp32alen = scale_expansion_zeroelim(cytabtlen, cytabt, cdytail,
+                                            temp32a);
+      cytabttlen = scale_expansion_zeroelim(abttlen, abtt, cdytail, cytabtt);
+      temp16alen = scale_expansion_zeroelim(cytabttlen, cytabtt, 2.0 * cdy,
+                                            temp16a);
+      temp16blen = scale_expansion_zeroelim(cytabttlen, cytabtt, cdytail,
+                                            temp16b);
+      temp32blen = fast_expansion_sum_zeroelim(temp16alen, temp16a,
+                                              temp16blen, temp16b, temp32b);
+      temp64len = fast_expansion_sum_zeroelim(temp32alen, temp32a,
+                                              temp32blen, temp32b, temp64);
+      finlength = fast_expansion_sum_zeroelim(finlength, finnow, temp64len,
+                                              temp64, finother);
+      finswap = finnow; finnow = finother; finother = finswap;
+    }
+  }
+
+  return finnow[finlength - 1];
+}
+
+REAL incircle(pa, pb, pc, pd)
+point pa;
+point pb;
+point pc;
+point pd;
+{
+  REAL adx, bdx, cdx, ady, bdy, cdy;
+  REAL bdxcdy, cdxbdy, cdxady, adxcdy, adxbdy, bdxady;
+  REAL alift, blift, clift;
+  REAL det;
+  REAL permanent, errbound;
+
+  incirclecount++;
+
+  adx = pa[0] - pd[0];
+  bdx = pb[0] - pd[0];
+  cdx = pc[0] - pd[0];
+  ady = pa[1] - pd[1];
+  bdy = pb[1] - pd[1];
+  cdy = pc[1] - pd[1];
+
+  bdxcdy = bdx * cdy;
+  cdxbdy = cdx * bdy;
+  alift = adx * adx + ady * ady;
+
+  cdxady = cdx * ady;
+  adxcdy = adx * cdy;
+  blift = bdx * bdx + bdy * bdy;
+
+  adxbdy = adx * bdy;
+  bdxady = bdx * ady;
+  clift = cdx * cdx + cdy * cdy;
+
+  det = alift * (bdxcdy - cdxbdy)
+      + blift * (cdxady - adxcdy)
+      + clift * (adxbdy - bdxady);
+
+  if (noexact) {
+    return det;
+  }
+
+  permanent = (Absolute(bdxcdy) + Absolute(cdxbdy)) * alift
+            + (Absolute(cdxady) + Absolute(adxcdy)) * blift
+            + (Absolute(adxbdy) + Absolute(bdxady)) * clift;
+  errbound = iccerrboundA * permanent;
+  if ((det > errbound) || (-det > errbound)) {
+    return det;
+  }
+
+  return incircleadapt(pa, pb, pc, pd, permanent);
+}
+
+/**                                                                         **/
+/**                                                                         **/
+/********* Determinant evaluation routines end here                  *********/
+
+/*****************************************************************************/
+/*                                                                           */
+/*  triangleinit()   Initialize some variables.                              */
+/*                                                                           */
+/*****************************************************************************/
+
+void triangleinit()
+{
+  points.maxitems = triangles.maxitems = shelles.maxitems = viri.maxitems =
+    badsegments.maxitems = badtriangles.maxitems = splaynodes.maxitems = 0l;
+  points.itembytes = triangles.itembytes = shelles.itembytes = viri.itembytes =
+    badsegments.itembytes = badtriangles.itembytes = splaynodes.itembytes = 0;
+  recenttri.tri = (triangle *) NULL;    /* No triangle has been visited yet. */
+  samples = 1;            /* Point location should take at least one sample. */
+  checksegments = 0;      /* There are no segments in the triangulation yet. */
+  incirclecount = counterclockcount = hyperbolacount = 0;
+  circumcentercount = circletopcount = 0;
+  randomseed = 1;
+
+  exactinit();                     /* Initialize exact arithmetic constants. */
+}
+
+/*****************************************************************************/
+/*                                                                           */
+/*  randomnation()   Generate a random number between 0 and `choices' - 1.   */
+/*                                                                           */
+/*  This is a simple linear congruential random number generator.  Hence, it */
+/*  is a bad random number generator, but good enough for most randomized    */
+/*  geometric algorithms.                                                    */
+/*                                                                           */
+/*****************************************************************************/
+
+unsigned long randomnation(choices)
+unsigned int choices;
+{
+  randomseed = (randomseed * 1366l + 150889l) % 714025l;
+  return randomseed / (714025l / choices + 1);
+}
+
+/********* Mesh quality testing routines begin here                  *********/
+/**                                                                         **/
+/**                                                                         **/
+
+/*****************************************************************************/
+/*                                                                           */
+/*  checkmesh()   Test the mesh for topological consistency.                 */
+/*                                                                           */
+/*****************************************************************************/
+
+#ifndef REDUCED
+
+void checkmesh()
+{
+  struct triedge triangleloop;
+  struct triedge oppotri, oppooppotri;
+  point triorg, tridest, triapex;
+  point oppoorg, oppodest;
+  int horrors;
+  int saveexact;
+  triangle ptr;                         /* Temporary variable used by sym(). */
+
+  /* Temporarily turn on exact arithmetic if it's off. */
+  saveexact = noexact;
+  noexact = 0;
+  if (!quiet) {
+    printf("  Checking consistency of mesh...\n");
+  }
+  horrors = 0;
+  /* Run through the list of triangles, checking each one. */
+  traversalinit(&triangles);
+  triangleloop.tri = triangletraverse();
+  while (triangleloop.tri != (triangle *) NULL) {
+    /* Check all three edges of the triangle. */
+    for (triangleloop.orient = 0; triangleloop.orient < 3;
+         triangleloop.orient++) {
+      org(triangleloop, triorg);
+      dest(triangleloop, tridest);
+      if (triangleloop.orient == 0) {       /* Only test for inversion once. */
+        /* Test if the triangle is flat or inverted. */
+        apex(triangleloop, triapex);
+        if (counterclockwise(triorg, tridest, triapex) <= 0.0) {
+          printf("  !! !! Inverted ");
+          printtriangle(&triangleloop);
+          horrors++;
+        }
+      }
+      /* Find the neighboring triangle on this edge. */
+      sym(triangleloop, oppotri);
+      if (oppotri.tri != dummytri) {
+        /* Check that the triangle's neighbor knows it's a neighbor. */
+        sym(oppotri, oppooppotri);
+        if ((triangleloop.tri != oppooppotri.tri)
+            || (triangleloop.orient != oppooppotri.orient)) {
+          printf("  !! !! Asymmetric triangle-triangle bond:\n");
+          if (triangleloop.tri == oppooppotri.tri) {
+            printf("   (Right triangle, wrong orientation)\n");
+          }
+          printf("    First ");
+          printtriangle(&triangleloop);
+          printf("    Second (nonreciprocating) ");
+          printtriangle(&oppotri);
+          horrors++;
+        }
+        /* Check that both triangles agree on the identities */
+        /*   of their shared vertices.                       */
+        org(oppotri, oppoorg);
+        dest(oppotri, oppodest);
+        if ((triorg != oppodest) || (tridest != oppoorg)) {
+          printf("  !! !! Mismatched edge coordinates between two triangles:\n"
+                 );
+          printf("    First mismatched ");
+          printtriangle(&triangleloop);
+          printf("    Second mismatched ");
+          printtriangle(&oppotri);
+          horrors++;
+        }
+      }
+    }
+    triangleloop.tri = triangletraverse();
+  }
+  if (horrors == 0) {
+    if (!quiet) {
+      printf("  In my studied opinion, the mesh appears to be consistent.\n");
+    }
+  } else if (horrors == 1) {
+    printf("  !! !! !! !! Precisely one festering wound discovered.\n");
+  } else {
+    printf("  !! !! !! !! %d abominations witnessed.\n", horrors);
+  }
+  /* Restore the status of exact arithmetic. */
+  noexact = saveexact;
+}
+
+#endif /* not REDUCED */
+
+/*****************************************************************************/
+/*                                                                           */
+/*  checkdelaunay()   Ensure that the mesh is (constrained) Delaunay.        */
+/*                                                                           */
+/*****************************************************************************/
+
+#ifndef REDUCED
+
+void checkdelaunay()
+{
+  struct triedge triangleloop;
+  struct triedge oppotri;
+  struct edge opposhelle;
+  point triorg, tridest, triapex;
+  point oppoapex;
+  int shouldbedelaunay;
+  int horrors;
+  int saveexact;
+  triangle ptr;                         /* Temporary variable used by sym(). */
+  shelle sptr;                      /* Temporary variable used by tspivot(). */
+
+  /* Temporarily turn on exact arithmetic if it's off. */
+  saveexact = noexact;
+  noexact = 0;
+  if (!quiet) {
+    printf("  Checking Delaunay property of mesh...\n");
+  }
+  horrors = 0;
+  /* Run through the list of triangles, checking each one. */
+  traversalinit(&triangles);
+  triangleloop.tri = triangletraverse();
+  while (triangleloop.tri != (triangle *) NULL) {
+    /* Check all three edges of the triangle. */
+    for (triangleloop.orient = 0; triangleloop.orient < 3;
+         triangleloop.orient++) {
+      org(triangleloop, triorg);
+      dest(triangleloop, tridest);
+      apex(triangleloop, triapex);
+      sym(triangleloop, oppotri);
+      apex(oppotri, oppoapex);
+      /* Only test that the edge is locally Delaunay if there is an   */
+      /*   adjoining triangle whose pointer is larger (to ensure that */
+      /*   each pair isn't tested twice).                             */
+      shouldbedelaunay = (oppotri.tri != dummytri)
+            && (triapex != (point) NULL) && (oppoapex != (point) NULL)
+            && (triangleloop.tri < oppotri.tri);
+      if (checksegments && shouldbedelaunay) {
+        /* If a shell edge separates the triangles, then the edge is */
+        /*   constrained, so no local Delaunay test should be done.  */
+        tspivot(triangleloop, opposhelle);
+        if (opposhelle.sh != dummysh){
+          shouldbedelaunay = 0;
+        }
+      }
+      if (shouldbedelaunay) {
+        if (incircle(triorg, tridest, triapex, oppoapex) > 0.0) {
+          printf("  !! !! Non-Delaunay pair of triangles:\n");
+          printf("    First non-Delaunay ");
+          printtriangle(&triangleloop);
+          printf("    Second non-Delaunay ");
+          printtriangle(&oppotri);
+          horrors++;
+        }
+      }
+    }
+    triangleloop.tri = triangletraverse();
+  }
+  if (horrors == 0) {
+    if (!quiet) {
+      printf(
+  "  By virtue of my perceptive intelligence, I declare the mesh Delaunay.\n");
+    }
+  } else if (horrors == 1) {
+    printf(
+         "  !! !! !! !! Precisely one terrifying transgression identified.\n");
+  } else {
+    printf("  !! !! !! !! %d obscenities viewed with horror.\n", horrors);
+  }
+  /* Restore the status of exact arithmetic. */
+  noexact = saveexact;
+}
+
+#endif /* not REDUCED */
+
+/*****************************************************************************/
+/*                                                                           */
+/*  enqueuebadtri()   Add a bad triangle to the end of a queue.              */
+/*                                                                           */
+/*  The queue is actually a set of 64 queues.  I use multiple queues to give */
+/*  priority to smaller angles.  I originally implemented a heap, but the    */
+/*  queues are (to my surprise) much faster.                                 */
+/*                                                                           */
+/*****************************************************************************/
+
+#ifndef CDT_ONLY
+
+void enqueuebadtri(instri, angle, insapex, insorg, insdest)
+struct triedge *instri;
+REAL angle;
+point insapex;
+point insorg;
+point insdest;
+{
+  struct badface *newface;
+  int queuenumber;
+
+  if (verbose > 2) {
+    printf("  Queueing bad triangle:\n");
+    printf("    (%.12g, %.12g) (%.12g, %.12g) (%.12g, %.12g)\n", insorg[0],
+           insorg[1], insdest[0], insdest[1], insapex[0], insapex[1]);
+  }
+  /* Allocate space for the bad triangle. */
+  newface = (struct badface *) poolalloc(&badtriangles);
+  triedgecopy(*instri, newface->badfacetri);
+  newface->key = angle;
+  newface->faceapex = insapex;
+  newface->faceorg = insorg;
+  newface->facedest = insdest;
+  newface->nextface = (struct badface *) NULL;
+  /* Determine the appropriate queue to put the bad triangle into. */
+  if (angle > 0.6) {
+    queuenumber = (int) (160.0 * (angle - 0.6));
+    if (queuenumber > 63) {
+      queuenumber = 63;
+    }
+  } else {
+    /* It's not a bad angle; put the triangle in the lowest-priority queue. */
+    queuenumber = 0;
+  }
+  /* Add the triangle to the end of a queue. */
+  *queuetail[queuenumber] = newface;
+  /* Maintain a pointer to the NULL pointer at the end of the queue. */
+  queuetail[queuenumber] = &newface->nextface;
+}
+
+#endif /* not CDT_ONLY */
+
+/*****************************************************************************/
+/*                                                                           */
+/*  dequeuebadtri()   Remove a triangle from the front of the queue.         */
+/*                                                                           */
+/*****************************************************************************/
+
+#ifndef CDT_ONLY
+
+struct badface *dequeuebadtri()
+{
+  struct badface *result;
+  int queuenumber;
+
+  /* Look for a nonempty queue. */
+  for (queuenumber = 63; queuenumber >= 0; queuenumber--) {
+    result = queuefront[queuenumber];
+    if (result != (struct badface *) NULL) {
+      /* Remove the triangle from the queue. */
+      queuefront[queuenumber] = result->nextface;
+      /* Maintain a pointer to the NULL pointer at the end of the queue. */
+      if (queuefront[queuenumber] == (struct badface *) NULL) {
+        queuetail[queuenumber] = &queuefront[queuenumber];
+      }
+      return result;
+    }
+  }
+  return (struct badface *) NULL;
+}
+
+#endif /* not CDT_ONLY */
+
+/*****************************************************************************/
+/*                                                                           */
+/*  checkedge4encroach()   Check a segment to see if it is encroached; add   */
+/*                         it to the list if it is.                          */
+/*                                                                           */
+/*  An encroached segment is an unflippable edge that has a point in its     */
+/*  diametral circle (that is, it faces an angle greater than 90 degrees).   */
+/*  This definition is due to Ruppert.                                       */
+/*                                                                           */
+/*  Returns a nonzero value if the edge is encroached.                       */
+/*                                                                           */
+/*****************************************************************************/
+
+#ifndef CDT_ONLY
+
+int checkedge4encroach(testedge)
+struct edge *testedge;
+{
+  struct triedge neighbortri;
+  struct edge testsym;
+  struct edge *badedge;
+  int addtolist;
+  int sides;
+  point eorg, edest, eapex;
+  triangle ptr;                     /* Temporary variable used by stpivot(). */
+
+  addtolist = 0;
+  sides = 0;
+
+  sorg(*testedge, eorg);
+  sdest(*testedge, edest);
+  /* Check one neighbor of the shell edge. */
+  stpivot(*testedge, neighbortri);
+  /* Does the neighbor exist, or is this a boundary edge? */
+  if (neighbortri.tri != dummytri) {
+    sides++;
+    /* Find a vertex opposite this edge. */
+    apex(neighbortri, eapex);
+    /* Check whether the vertex is inside the diametral circle of the  */
+    /*   shell edge.  Pythagoras' Theorem is used to check whether the */
+    /*   angle at the vertex is greater than 90 degrees.               */
+    if (eapex[0] * (eorg[0] + edest[0]) + eapex[1] * (eorg[1] + edest[1]) >
+        eapex[0] * eapex[0] + eorg[0] * edest[0] +
+        eapex[1] * eapex[1] + eorg[1] * edest[1]) {
+      addtolist = 1;
+    }
+  }
+  /* Check the other neighbor of the shell edge. */
+  ssym(*testedge, testsym);
+  stpivot(testsym, neighbortri);
+  /* Does the neighbor exist, or is this a boundary edge? */
+  if (neighbortri.tri != dummytri) {
+    sides++;
+    /* Find the other vertex opposite this edge. */
+    apex(neighbortri, eapex);
+    /* Check whether the vertex is inside the diametral circle of the  */
+    /*   shell edge.  Pythagoras' Theorem is used to check whether the */
+    /*   angle at the vertex is greater than 90 degrees.               */
+    if (eapex[0] * (eorg[0] + edest[0]) +
+        eapex[1] * (eorg[1] + edest[1]) >
+        eapex[0] * eapex[0] + eorg[0] * edest[0] +
+        eapex[1] * eapex[1] + eorg[1] * edest[1]) {
+      addtolist += 2;
+    }
+  }
+
+  if (addtolist && (!nobisect || ((nobisect == 1) && (sides == 2)))) {
+    if (verbose > 2) {
+      printf("  Queueing encroached segment (%.12g, %.12g) (%.12g, %.12g).\n",
+             eorg[0], eorg[1], edest[0], edest[1]);
+    }
+    /* Add the shell edge to the list of encroached segments. */
+    /*   Be sure to get the orientation right.                */
+    badedge = (struct edge *) poolalloc(&badsegments);
+    if (addtolist == 1) {
+      shellecopy(*testedge, *badedge);
+    } else {
+      shellecopy(testsym, *badedge);
+    }
+  }
+  return addtolist;
+}
+
+#endif /* not CDT_ONLY */
+
+/*****************************************************************************/
+/*                                                                           */
+/*  testtriangle()   Test a face for quality measures.                       */
+/*                                                                           */
+/*  Tests a triangle to see if it satisfies the minimum angle condition and  */
+/*  the maximum area condition.  Triangles that aren't up to spec are added  */
+/*  to the bad triangle queue.                                               */
+/*                                                                           */
+/*****************************************************************************/
+
+#ifndef CDT_ONLY
+
+void testtriangle(testtri)
+struct triedge *testtri;
+{
+  struct triedge sametesttri;
+  struct edge edge1, edge2;
+  point torg, tdest, tapex;
+  point anglevertex;
+  REAL dxod, dyod, dxda, dyda, dxao, dyao;
+  REAL dxod2, dyod2, dxda2, dyda2, dxao2, dyao2;
+  REAL apexlen, orglen, destlen;
+  REAL angle;
+  REAL area;
+  shelle sptr;                      /* Temporary variable used by tspivot(). */
+
+  org(*testtri, torg);
+  dest(*testtri, tdest);
+  apex(*testtri, tapex);
+  dxod = torg[0] - tdest[0];
+  dyod = torg[1] - tdest[1];
+  dxda = tdest[0] - tapex[0];
+  dyda = tdest[1] - tapex[1];
+  dxao = tapex[0] - torg[0];
+  dyao = tapex[1] - torg[1];
+  dxod2 = dxod * dxod;
+  dyod2 = dyod * dyod;
+  dxda2 = dxda * dxda;
+  dyda2 = dyda * dyda;
+  dxao2 = dxao * dxao;
+  dyao2 = dyao * dyao;
+  /* Find the lengths of the triangle's three edges. */
+  apexlen = dxod2 + dyod2;
+  orglen = dxda2 + dyda2;
+  destlen = dxao2 + dyao2;
+  if ((apexlen < orglen) && (apexlen < destlen)) {
+    /* The edge opposite the apex is shortest. */
+    /* Find the square of the cosine of the angle at the apex. */
+    angle = dxda * dxao + dyda * dyao;
+    angle = angle * angle / (orglen * destlen);
+    anglevertex = tapex;
+    lnext(*testtri, sametesttri);
+    tspivot(sametesttri, edge1);
+    lnextself(sametesttri);
+    tspivot(sametesttri, edge2);
+  } else if (orglen < destlen) {
+    /* The edge opposite the origin is shortest. */
+    /* Find the square of the cosine of the angle at the origin. */
+    angle = dxod * dxao + dyod * dyao;
+    angle = angle * angle / (apexlen * destlen);
+    anglevertex = torg;
+    tspivot(*testtri, edge1);
+    lprev(*testtri, sametesttri);
+    tspivot(sametesttri, edge2);
+  } else {
+    /* The edge opposite the destination is shortest. */
+    /* Find the square of the cosine of the angle at the destination. */
+    angle = dxod * dxda + dyod * dyda;
+    angle = angle * angle / (apexlen * orglen);
+    anglevertex = tdest;
+    tspivot(*testtri, edge1);
+    lnext(*testtri, sametesttri);
+    tspivot(sametesttri, edge2);
+  }
+  /* Check if both edges that form the angle are segments. */
+  if ((edge1.sh != dummysh) && (edge2.sh != dummysh)) {
+    /* The angle is a segment intersection. */
+    if ((angle > 0.9924) && !quiet) {                  /* Roughly 5 degrees. */
+      if (angle > 1.0) {
+        /* Beware of a floating exception in acos(). */
+        angle = 1.0;
+      }
+      /* Find the actual angle in degrees, for printing. */
+      angle = acos(sqrt(angle)) * (180.0 / PI);
+      printf(
+      "Warning:  Small angle (%.4g degrees) between segments at point\n",
+             angle);
+      printf("  (%.12g, %.12g)\n", anglevertex[0], anglevertex[1]);
+    }
+    /* Don't add this bad triangle to the list; there's nothing that */
+    /*   can be done about a small angle between two segments.       */
+    angle = 0.0;
+  }
+  /* Check whether the angle is smaller than permitted. */
+  if (angle > goodangle) {
+    /* Add this triangle to the list of bad triangles. */
+    enqueuebadtri(testtri, angle, tapex, torg, tdest);
+    return;
+  }
+  if (vararea || fixedarea) {
+    /* Check whether the area is larger than permitted. */
+    area = 0.5 * (dxod * dyda - dyod * dxda);
+    if (fixedarea && (area > maxarea)) {
+      /* Add this triangle to the list of bad triangles. */
+      enqueuebadtri(testtri, angle, tapex, torg, tdest);
+    } else if (vararea) {
+      /* Nonpositive area constraints are treated as unconstrained. */
+      if ((area > areabound(*testtri)) && (areabound(*testtri) > 0.0)) {
+        /* Add this triangle to the list of bad triangles. */
+        enqueuebadtri(testtri, angle, tapex, torg, tdest);
+      }
+    }
+  }
+}
+
+#endif /* not CDT_ONLY */
+
+/**                                                                         **/
+/**                                                                         **/
+/********* Mesh quality testing routines end here                    *********/
+
+/********* Point location routines begin here                        *********/
+/**                                                                         **/
+/**                                                                         **/
+
+/*****************************************************************************/
+/*                                                                           */
+/*  makepointmap()   Construct a mapping from points to triangles to improve  */
+/*                  the speed of point location for segment insertion.       */
+/*                                                                           */
+/*  Traverses all the triangles, and provides each corner of each triangle   */
+/*  with a pointer to that triangle.  Of course, pointers will be            */
+/*  overwritten by other pointers because (almost) each point is a corner    */
+/*  of several triangles, but in the end every point will point to some      */
+/*  triangle that contains it.                                               */
+/*                                                                           */
+/*****************************************************************************/
+
+void makepointmap()
+{
+  struct triedge triangleloop;
+  point triorg;
+
+  if (verbose) {
+    printf("    Constructing mapping from points to triangles.\n");
+  }
+  traversalinit(&triangles);
+  triangleloop.tri = triangletraverse();
+  while (triangleloop.tri != (triangle *) NULL) {
+    /* Check all three points of the triangle. */
+    for (triangleloop.orient = 0; triangleloop.orient < 3;
+         triangleloop.orient++) {
+      org(triangleloop, triorg);
+      setpoint2tri(triorg, encode(triangleloop));
+    }
+    triangleloop.tri = triangletraverse();
+  }
+}
+
+/*****************************************************************************/
+/*                                                                           */
+/*  preciselocate()   Find a triangle or edge containing a given point.      */
+/*                                                                           */
+/*  Begins its search from `searchtri'.  It is important that `searchtri'    */
+/*  be a handle with the property that `searchpoint' is strictly to the left */
+/*  of the edge denoted by `searchtri', or is collinear with that edge and   */
+/*  does not intersect that edge.  (In particular, `searchpoint' should not  */
+/*  be the origin or destination of that edge.)                              */
+/*                                                                           */
+/*  These conditions are imposed because preciselocate() is normally used in */
+/*  one of two situations:                                                   */
+/*                                                                           */
+/*  (1)  To try to find the location to insert a new point.  Normally, we    */
+/*       know an edge that the point is strictly to the left of.  In the     */
+/*       incremental Delaunay algorithm, that edge is a bounding box edge.   */
+/*       In Ruppert's Delaunay refinement algorithm for quality meshing,     */
+/*       that edge is the shortest edge of the triangle whose circumcenter   */
+/*       is being inserted.                                                  */
+/*                                                                           */
+/*  (2)  To try to find an existing point.  In this case, any edge on the    */
+/*       convex hull is a good starting edge.  The possibility that the      */
+/*       vertex one seeks is an endpoint of the starting edge must be        */
+/*       screened out before preciselocate() is called.                      */
+/*                                                                           */
+/*  On completion, `searchtri' is a triangle that contains `searchpoint'.    */
+/*                                                                           */
+/*  This implementation differs from that given by Guibas and Stolfi.  It    */
+/*  walks from triangle to triangle, crossing an edge only if `searchpoint'  */
+/*  is on the other side of the line containing that edge.  After entering   */
+/*  a triangle, there are two edges by which one can leave that triangle.    */
+/*  If both edges are valid (`searchpoint' is on the other side of both      */
+/*  edges), one of the two is chosen by drawing a line perpendicular to      */
+/*  the entry edge (whose endpoints are `forg' and `fdest') passing through  */
+/*  `fapex'.  Depending on which side of this perpendicular `searchpoint'    */
+/*  falls on, an exit edge is chosen.                                        */
+/*                                                                           */
+/*  This implementation is empirically faster than the Guibas and Stolfi     */
+/*  point location routine (which I originally used), which tends to spiral  */
+/*  in toward its target.                                                    */
+/*                                                                           */
+/*  Returns ONVERTEX if the point lies on an existing vertex.  `searchtri'   */
+/*  is a handle whose origin is the existing vertex.                         */
+/*                                                                           */
+/*  Returns ONEDGE if the point lies on a mesh edge.  `searchtri' is a       */
+/*  handle whose primary edge is the edge on which the point lies.           */
+/*                                                                           */
+/*  Returns INTRIANGLE if the point lies strictly within a triangle.         */
+/*  `searchtri' is a handle on the triangle that contains the point.         */
+/*                                                                           */
+/*  Returns OUTSIDE if the point lies outside the mesh.  `searchtri' is a    */
+/*  handle whose primary edge the point is to the right of.  This might      */
+/*  occur when the circumcenter of a triangle falls just slightly outside    */
+/*  the mesh due to floating-point roundoff error.  It also occurs when      */
+/*  seeking a hole or region point that a foolish user has placed outside    */
+/*  the mesh.                                                                */
+/*                                                                           */
+/*  WARNING:  This routine is designed for convex triangulations, and will   */
+/*  not generally work after the holes and concavities have been carved.     */
+/*  However, it can still be used to find the circumcenter of a triangle, as */
+/*  long as the search is begun from the triangle in question.               */
+/*                                                                           */
+/*****************************************************************************/
+
+enum locateresult preciselocate(searchpoint, searchtri)
+point searchpoint;
+struct triedge *searchtri;
+{
+  struct triedge backtracktri;
+  point forg, fdest, fapex;
+  point swappoint;
+  REAL orgorient, destorient;
+  int moveleft;
+  triangle ptr;                         /* Temporary variable used by sym(). */
+
+  if (verbose > 2) {
+    printf("  Searching for point (%.12g, %.12g).\n",
+           searchpoint[0], searchpoint[1]);
+  }
+  /* Where are we? */
+  org(*searchtri, forg);
+  dest(*searchtri, fdest);
+  apex(*searchtri, fapex);
+  while (1) {
+    if (verbose > 2) {
+      printf("    At (%.12g, %.12g) (%.12g, %.12g) (%.12g, %.12g)\n",
+             forg[0], forg[1], fdest[0], fdest[1], fapex[0], fapex[1]);
+    }
+    /* Check whether the apex is the point we seek. */
+    if ((fapex[0] == searchpoint[0]) && (fapex[1] == searchpoint[1])) {
+      lprevself(*searchtri);
+      return ONVERTEX;
+    }
+    /* Does the point lie on the other side of the line defined by the */
+    /*   triangle edge opposite the triangle's destination?            */
+    destorient = counterclockwise(forg, fapex, searchpoint);
+    /* Does the point lie on the other side of the line defined by the */
+    /*   triangle edge opposite the triangle's origin?                 */
+    orgorient = counterclockwise(fapex, fdest, searchpoint);
+    if (destorient > 0.0) {
+      if (orgorient > 0.0) {
+        /* Move left if the inner product of (fapex - searchpoint) and  */
+        /*   (fdest - forg) is positive.  This is equivalent to drawing */
+        /*   a line perpendicular to the line (forg, fdest) passing     */
+        /*   through `fapex', and determining which side of this line   */
+        /*   `searchpoint' falls on.                                    */
+        moveleft = (fapex[0] - searchpoint[0]) * (fdest[0] - forg[0]) +
+                   (fapex[1] - searchpoint[1]) * (fdest[1] - forg[1]) > 0.0;
+      } else {
+        moveleft = 1;
+      }
+    } else {
+      if (orgorient > 0.0) {
+        moveleft = 0;
+      } else {
+        /* The point we seek must be on the boundary of or inside this */
+        /*   triangle.                                                 */
+        if (destorient == 0.0) {
+          lprevself(*searchtri);
+          return ONEDGE;
+        }
+        if (orgorient == 0.0) {
+          lnextself(*searchtri);
+          return ONEDGE;
+        }
+        return INTRIANGLE;
+      }
+    }
+
+    /* Move to another triangle.  Leave a trace `backtracktri' in case */
+    /*   floating-point roundoff or some such bogey causes us to walk  */
+    /*   off a boundary of the triangulation.  We can just bounce off  */
+    /*   the boundary as if it were an elastic band.                   */
+    if (moveleft) {
+      lprev(*searchtri, backtracktri);
+      fdest = fapex;
+    } else {
+      lnext(*searchtri, backtracktri);
+      forg = fapex;
+    }
+    sym(backtracktri, *searchtri);
+
+    /* Check for walking off the edge. */
+    if (searchtri->tri == dummytri) {
+      /* Turn around. */
+      triedgecopy(backtracktri, *searchtri);
+      swappoint = forg;
+      forg = fdest;
+      fdest = swappoint;
+      apex(*searchtri, fapex);
+      /* Check if the point really is beyond the triangulation boundary. */
+      destorient = counterclockwise(forg, fapex, searchpoint);
+      orgorient = counterclockwise(fapex, fdest, searchpoint);
+      if ((orgorient < 0.0) && (destorient < 0.0)) {
+        return OUTSIDE;
+      }
+    } else {
+      apex(*searchtri, fapex);
+    }
+  }
+}
+
+/*****************************************************************************/
+/*                                                                           */
+/*  locate()   Find a triangle or edge containing a given point.             */
+/*                                                                           */
+/*  Searching begins from one of:  the input `searchtri', a recently         */
+/*  encountered triangle `recenttri', or from a triangle chosen from a       */
+/*  random sample.  The choice is made by determining which triangle's       */
+/*  origin is closest to the point we are searcing for.  Normally,           */
+/*  `searchtri' should be a handle on the convex hull of the triangulation.  */
+/*                                                                           */
+/*  Details on the random sampling method can be found in the Mucke, Saias,  */
+/*  and Zhu paper cited in the header of this code.                          */
+/*                                                                           */
+/*  On completion, `searchtri' is a triangle that contains `searchpoint'.    */
+/*                                                                           */
+/*  Returns ONVERTEX if the point lies on an existing vertex.  `searchtri'   */
+/*  is a handle whose origin is the existing vertex.                         */
+/*                                                                           */
+/*  Returns ONEDGE if the point lies on a mesh edge.  `searchtri' is a       */
+/*  handle whose primary edge is the edge on which the point lies.           */
+/*                                                                           */
+/*  Returns INTRIANGLE if the point lies strictly within a triangle.         */
+/*  `searchtri' is a handle on the triangle that contains the point.         */
+/*                                                                           */
+/*  Returns OUTSIDE if the point lies outside the mesh.  `searchtri' is a    */
+/*  handle whose primary edge the point is to the right of.  This might      */
+/*  occur when the circumcenter of a triangle falls just slightly outside    */
+/*  the mesh due to floating-point roundoff error.  It also occurs when      */
+/*  seeking a hole or region point that a foolish user has placed outside    */
+/*  the mesh.                                                                */
+/*                                                                           */
+/*  WARNING:  This routine is designed for convex triangulations, and will   */
+/*  not generally work after the holes and concavities have been carved.     */
+/*                                                                           */
+/*****************************************************************************/
+
+enum locateresult locate(searchpoint, searchtri)
+point searchpoint;
+struct triedge *searchtri;
+{
+  VOID **sampleblock;
+  triangle *firsttri;
+  struct triedge sampletri;
+  point torg, tdest;
+  unsigned long alignptr;
+  REAL searchdist, dist;
+  REAL ahead;
+  long sampleblocks, samplesperblock, samplenum;
+  long triblocks;
+  long i, j;
+  triangle ptr;                         /* Temporary variable used by sym(). */
+
+  if (verbose > 2) {
+    printf("  Randomly sampling for a triangle near point (%.12g, %.12g).\n",
+           searchpoint[0], searchpoint[1]);
+  }
+  /* Record the distance from the suggested starting triangle to the */
+  /*   point we seek.                                                */
+  org(*searchtri, torg);
+  searchdist = (searchpoint[0] - torg[0]) * (searchpoint[0] - torg[0])
+             + (searchpoint[1] - torg[1]) * (searchpoint[1] - torg[1]);
+  if (verbose > 2) {
+    printf("    Boundary triangle has origin (%.12g, %.12g).\n",
+           torg[0], torg[1]);
+  }
+
+  /* If a recently encountered triangle has been recorded and has not been */
+  /*   deallocated, test it as a good starting point.                      */
+  if (recenttri.tri != (triangle *) NULL) {
+    if (recenttri.tri[3] != (triangle) NULL) {
+      org(recenttri, torg);
+      if ((torg[0] == searchpoint[0]) && (torg[1] == searchpoint[1])) {
+        triedgecopy(recenttri, *searchtri);
+        return ONVERTEX;
+      }
+      dist = (searchpoint[0] - torg[0]) * (searchpoint[0] - torg[0])
+           + (searchpoint[1] - torg[1]) * (searchpoint[1] - torg[1]);
+      if (dist < searchdist) {
+        triedgecopy(recenttri, *searchtri);
+        searchdist = dist;
+        if (verbose > 2) {
+          printf("    Choosing recent triangle with origin (%.12g, %.12g).\n",
+                 torg[0], torg[1]);
+        }
+      }
+    }
+  }
+
+  /* The number of random samples taken is proportional to the cube root of */
+  /*   the number of triangles in the mesh.  The next bit of code assumes   */
+  /*   that the number of triangles increases monotonically.                */
+  while (SAMPLEFACTOR * samples * samples * samples < triangles.items) {
+    samples++;
+  }
+  triblocks = (triangles.maxitems + TRIPERBLOCK - 1) / TRIPERBLOCK;
+  samplesperblock = 1 + (samples / triblocks);
+  sampleblocks = samples / samplesperblock;
+  sampleblock = triangles.firstblock;
+  sampletri.orient = 0;
+  for (i = 0; i < sampleblocks; i++) {
+    alignptr = (unsigned long) (sampleblock + 1);
+    firsttri = (triangle *) (alignptr + (unsigned long) triangles.alignbytes
+                          - (alignptr % (unsigned long) triangles.alignbytes));
+    for (j = 0; j < samplesperblock; j++) {
+      if (i == triblocks - 1) {
+        samplenum = randomnation((int)
+                                 (triangles.maxitems - (i * TRIPERBLOCK)));
+      } else {
+        samplenum = randomnation(TRIPERBLOCK);
+      }
+      sampletri.tri = (triangle *)
+                      (firsttri + (samplenum * triangles.itemwords));
+      if (sampletri.tri[3] != (triangle) NULL) {
+        org(sampletri, torg);
+        dist = (searchpoint[0] - torg[0]) * (searchpoint[0] - torg[0])
+             + (searchpoint[1] - torg[1]) * (searchpoint[1] - torg[1]);
+        if (dist < searchdist) {
+          triedgecopy(sampletri, *searchtri);
+          searchdist = dist;
+          if (verbose > 2) {
+            printf("    Choosing triangle with origin (%.12g, %.12g).\n",
+                   torg[0], torg[1]);
+          }
+        }
+      }
+    }
+    sampleblock = (VOID **) *sampleblock;
+  }
+  /* Where are we? */
+  org(*searchtri, torg);
+  dest(*searchtri, tdest);
+  /* Check the starting triangle's vertices. */
+  if ((torg[0] == searchpoint[0]) && (torg[1] == searchpoint[1])) {
+    return ONVERTEX;
+  }
+  if ((tdest[0] == searchpoint[0]) && (tdest[1] == searchpoint[1])) {
+    lnextself(*searchtri);
+    return ONVERTEX;
+  }
+  /* Orient `searchtri' to fit the preconditions of calling preciselocate(). */
+  ahead = counterclockwise(torg, tdest, searchpoint);
+  if (ahead < 0.0) {
+    /* Turn around so that `searchpoint' is to the left of the */
+    /*   edge specified by `searchtri'.                        */
+    symself(*searchtri);
+  } else if (ahead == 0.0) {
+    /* Check if `searchpoint' is between `torg' and `tdest'. */
+    if (((torg[0] < searchpoint[0]) == (searchpoint[0] < tdest[0]))
+        && ((torg[1] < searchpoint[1]) == (searchpoint[1] < tdest[1]))) {
+      return ONEDGE;
+    }
+  }
+  return preciselocate(searchpoint, searchtri);
+}
+
+/**                                                                         **/
+/**                                                                         **/
+/********* Point location routines end here                          *********/
+
+/********* Mesh transformation routines begin here                   *********/
+/**                                                                         **/
+/**                                                                         **/
+
+/*****************************************************************************/
+/*                                                                           */
+/*  insertshelle()   Create a new shell edge and insert it between two       */
+/*                   triangles.                                              */
+/*                                                                           */
+/*  The new shell edge is inserted at the edge described by the handle       */
+/*  `tri'.  Its vertices are properly initialized.  The marker `shellemark'  */
+/*  is applied to the shell edge and, if appropriate, its vertices.          */
+/*                                                                           */
+/*****************************************************************************/
+
+void insertshelle(tri, shellemark)
+struct triedge *tri;          /* Edge at which to insert the new shell edge. */
+int shellemark;                            /* Marker for the new shell edge. */
+{
+  struct triedge oppotri;
+  struct edge newshelle;
+  point triorg, tridest;
+  triangle ptr;                         /* Temporary variable used by sym(). */
+  shelle sptr;                      /* Temporary variable used by tspivot(). */
+
+  /* Mark points if possible. */
+  org(*tri, triorg);
+  dest(*tri, tridest);
+  if (pointmark(triorg) == 0) {
+    setpointmark(triorg, shellemark);
+  }
+  if (pointmark(tridest) == 0) {
+    setpointmark(tridest, shellemark);
+  }
+  /* Check if there's already a shell edge here. */
+  tspivot(*tri, newshelle);
+  if (newshelle.sh == dummysh) {
+    /* Make new shell edge and initialize its vertices. */
+    makeshelle(&newshelle);
+    setsorg(newshelle, tridest);
+    setsdest(newshelle, triorg);
+    /* Bond new shell edge to the two triangles it is sandwiched between. */
+    /*   Note that the facing triangle `oppotri' might be equal to        */
+    /*   `dummytri' (outer space), but the new shell edge is bonded to it */
+    /*   all the same.                                                    */
+    tsbond(*tri, newshelle);
+    sym(*tri, oppotri);
+    ssymself(newshelle);
+    tsbond(oppotri, newshelle);
+    setmark(newshelle, shellemark);
+    if (verbose > 2) {
+      printf("  Inserting new ");
+      printshelle(&newshelle);
+    }
+  } else {
+    if (mark(newshelle) == 0) {
+      setmark(newshelle, shellemark);
+    }
+  }
+}
+
+/*****************************************************************************/
+/*                                                                           */
+/*  Terminology                                                              */
+/*                                                                           */
+/*  A "local transformation" replaces a small set of triangles with another  */
+/*  set of triangles.  This may or may not involve inserting or deleting a   */
+/*  point.                                                                   */
+/*                                                                           */
+/*  The term "casing" is used to describe the set of triangles that are      */
+/*  attached to the triangles being transformed, but are not transformed     */
+/*  themselves.  Think of the casing as a fixed hollow structure inside      */
+/*  which all the action happens.  A "casing" is only defined relative to    */
+/*  a single transformation; each occurrence of a transformation will        */
+/*  involve a different casing.                                              */
+/*                                                                           */
+/*  A "shell" is similar to a "casing".  The term "shell" describes the set  */
+/*  of shell edges (if any) that are attached to the triangles being         */
+/*  transformed.  However, I sometimes use "shell" to refer to a single      */
+/*  shell edge, so don't get confused.                                       */
+/*                                                                           */
+/*****************************************************************************/
+
+/*****************************************************************************/
+/*                                                                           */
+/*  flip()   Transform two triangles to two different triangles by flipping  */
+/*           an edge within a quadrilateral.                                 */
+/*                                                                           */
+/*  Imagine the original triangles, abc and bad, oriented so that the        */
+/*  shared edge ab lies in a horizontal plane, with the point b on the left  */
+/*  and the point a on the right.  The point c lies below the edge, and the  */
+/*  point d lies above the edge.  The `flipedge' handle holds the edge ab    */
+/*  of triangle abc, and is directed left, from vertex a to vertex b.        */
+/*                                                                           */
+/*  The triangles abc and bad are deleted and replaced by the triangles cdb  */
+/*  and dca.  The triangles that represent abc and bad are NOT deallocated;  */
+/*  they are reused for dca and cdb, respectively.  Hence, any handles that  */
+/*  may have held the original triangles are still valid, although not       */
+/*  directed as they were before.                                            */
+/*                                                                           */
+/*  Upon completion of this routine, the `flipedge' handle holds the edge    */
+/*  dc of triangle dca, and is directed down, from vertex d to vertex c.     */
+/*  (Hence, the two triangles have rotated counterclockwise.)                */
+/*                                                                           */
+/*  WARNING:  This transformation is geometrically valid only if the         */
+/*  quadrilateral adbc is convex.  Furthermore, this transformation is       */
+/*  valid only if there is not a shell edge between the triangles abc and    */
+/*  bad.  This routine does not check either of these preconditions, and     */
+/*  it is the responsibility of the calling routine to ensure that they are  */
+/*  met.  If they are not, the streets shall be filled with wailing and      */
+/*  gnashing of teeth.                                                       */
+/*                                                                           */
+/*****************************************************************************/
+
+void flip(flipedge)
+struct triedge *flipedge;                    /* Handle for the triangle abc. */
+{
+  struct triedge botleft, botright;
+  struct triedge topleft, topright;
+  struct triedge top;
+  struct triedge botlcasing, botrcasing;
+  struct triedge toplcasing, toprcasing;
+  struct edge botlshelle, botrshelle;
+  struct edge toplshelle, toprshelle;
+  point leftpoint, rightpoint, botpoint;
+  point farpoint;
+  triangle ptr;                         /* Temporary variable used by sym(). */
+  shelle sptr;                      /* Temporary variable used by tspivot(). */
+
+  /* Identify the vertices of the quadrilateral. */
+  org(*flipedge, rightpoint);
+  dest(*flipedge, leftpoint);
+  apex(*flipedge, botpoint);
+  sym(*flipedge, top);
+#ifdef SELF_CHECK
+  if (top.tri == dummytri) {
+    printf("Internal error in flip():  Attempt to flip on boundary.\n");
+    lnextself(*flipedge);
+    return;
+  }
+  if (checksegments) {
+    tspivot(*flipedge, toplshelle);
+    if (toplshelle.sh != dummysh) {
+      printf("Internal error in flip():  Attempt to flip a segment.\n");
+      lnextself(*flipedge);
+      return;
+    }
+  }
+#endif /* SELF_CHECK */
+  apex(top, farpoint);
+
+  /* Identify the casing of the quadrilateral. */
+  lprev(top, topleft);
+  sym(topleft, toplcasing);
+  lnext(top, topright);
+  sym(topright, toprcasing);
+  lnext(*flipedge, botleft);
+  sym(botleft, botlcasing);
+  lprev(*flipedge, botright);
+  sym(botright, botrcasing);
+  /* Rotate the quadrilateral one-quarter turn counterclockwise. */
+  bond(topleft, botlcasing);
+  bond(botleft, botrcasing);
+  bond(botright, toprcasing);
+  bond(topright, toplcasing);
+
+  if (checksegments) {
+    /* Check for shell edges and rebond them to the quadrilateral. */
+    tspivot(topleft, toplshelle);
+    tspivot(botleft, botlshelle);
+    tspivot(botright, botrshelle);
+    tspivot(topright, toprshelle);
+    if (toplshelle.sh == dummysh) {
+      tsdissolve(topright);
+    } else {
+      tsbond(topright, toplshelle);
+    }
+    if (botlshelle.sh == dummysh) {
+      tsdissolve(topleft);
+    } else {
+      tsbond(topleft, botlshelle);
+    }
+    if (botrshelle.sh == dummysh) {
+      tsdissolve(botleft);
+    } else {
+      tsbond(botleft, botrshelle);
+    }
+    if (toprshelle.sh == dummysh) {
+      tsdissolve(botright);
+    } else {
+      tsbond(botright, toprshelle);
+    }
+  }
+
+  /* New point assignments for the rotated quadrilateral. */
+  setorg(*flipedge, farpoint);
+  setdest(*flipedge, botpoint);
+  setapex(*flipedge, rightpoint);
+  setorg(top, botpoint);
+  setdest(top, farpoint);
+  setapex(top, leftpoint);
+  if (verbose > 2) {
+    printf("  Edge flip results in left ");
+    lnextself(topleft);
+    printtriangle(&topleft);
+    printf("  and right ");
+    printtriangle(flipedge);
+  }
+}
+
+/*****************************************************************************/
+/*                                                                           */
+/*  insertsite()   Insert a vertex into a Delaunay triangulation,            */
+/*                 performing flips as necessary to maintain the Delaunay    */
+/*                 property.                                                 */
+/*                                                                           */
+/*  The point `insertpoint' is located.  If `searchtri.tri' is not NULL,     */
+/*  the search for the containing triangle begins from `searchtri'.  If      */
+/*  `searchtri.tri' is NULL, a full point location procedure is called.      */
+/*  If `insertpoint' is found inside a triangle, the triangle is split into  */
+/*  three; if `insertpoint' lies on an edge, the edge is split in two,       */
+/*  thereby splitting the two adjacent triangles into four.  Edge flips are  */
+/*  used to restore the Delaunay property.  If `insertpoint' lies on an      */
+/*  existing vertex, no action is taken, and the value DUPLICATEPOINT is     */
+/*  returned.  On return, `searchtri' is set to a handle whose origin is the */
+/*  existing vertex.                                                         */
+/*                                                                           */
+/*  Normally, the parameter `splitedge' is set to NULL, implying that no     */
+/*  segment should be split.  In this case, if `insertpoint' is found to     */
+/*  lie on a segment, no action is taken, and the value VIOLATINGPOINT is    */
+/*  returned.  On return, `searchtri' is set to a handle whose primary edge  */
+/*  is the violated segment.                                                 */
+/*                                                                           */
+/*  If the calling routine wishes to split a segment by inserting a point in */
+/*  it, the parameter `splitedge' should be that segment.  In this case,     */
+/*  `searchtri' MUST be the triangle handle reached by pivoting from that    */
+/*  segment; no point location is done.                                      */
+/*                                                                           */
+/*  `segmentflaws' and `triflaws' are flags that indicate whether or not     */
+/*  there should be checks for the creation of encroached segments or bad    */
+/*  quality faces.  If a newly inserted point encroaches upon segments,      */
+/*  these segments are added to the list of segments to be split if          */
+/*  `segmentflaws' is set.  If bad triangles are created, these are added    */
+/*  to the queue if `triflaws' is set.                                       */
+/*                                                                           */
+/*  If a duplicate point or violated segment does not prevent the point      */
+/*  from being inserted, the return value will be ENCROACHINGPOINT if the    */
+/*  point encroaches upon a segment (and checking is enabled), or            */
+/*  SUCCESSFULPOINT otherwise.  In either case, `searchtri' is set to a      */
+/*  handle whose origin is the newly inserted vertex.                        */
+/*                                                                           */
+/*  insertsite() does not use flip() for reasons of speed; some              */
+/*  information can be reused from edge flip to edge flip, like the          */
+/*  locations of shell edges.                                                */
+/*                                                                           */
+/*****************************************************************************/
+
+enum insertsiteresult insertsite(insertpoint, searchtri, splitedge,
+                                 segmentflaws, triflaws)
+point insertpoint;
+struct triedge *searchtri;
+struct edge *splitedge;
+int segmentflaws;
+int triflaws;
+{
+  struct triedge horiz;
+  struct triedge top;
+  struct triedge botleft, botright;
+  struct triedge topleft, topright;
+  struct triedge newbotleft, newbotright;
+  struct triedge newtopright;
+  struct triedge botlcasing, botrcasing;
+  struct triedge toplcasing, toprcasing;
+  struct triedge testtri;
+  struct edge botlshelle, botrshelle;
+  struct edge toplshelle, toprshelle;
+  struct edge brokenshelle;
+  struct edge checkshelle;
+  struct edge rightedge;
+  struct edge newedge;
+  struct edge *encroached;
+  point first;
+  point leftpoint, rightpoint, botpoint, toppoint, farpoint;
+  REAL attrib;
+  REAL area;
+  enum insertsiteresult success;
+  enum locateresult intersect;
+  int doflip;
+  int mirrorflag;
+  int i;
+  triangle ptr;                         /* Temporary variable used by sym(). */
+  shelle sptr;         /* Temporary variable used by spivot() and tspivot(). */
+
+  if (verbose > 1) {
+    printf("  Inserting (%.12g, %.12g).\n", insertpoint[0], insertpoint[1]);
+  }
+  if (splitedge == (struct edge *) NULL) {
+    /* Find the location of the point to be inserted.  Check if a good */
+    /*   starting triangle has already been provided by the caller.    */
+    if (searchtri->tri == (triangle *) NULL) {
+      /* Find a boundary triangle. */
+      horiz.tri = dummytri;
+      horiz.orient = 0;
+      symself(horiz);
+      /* Search for a triangle containing `insertpoint'. */
+      intersect = locate(insertpoint, &horiz);
+    } else {
+      /* Start searching from the triangle provided by the caller. */
+      triedgecopy(*searchtri, horiz);
+      intersect = preciselocate(insertpoint, &horiz);
+    }
+  } else {
+    /* The calling routine provides the edge in which the point is inserted. */
+    triedgecopy(*searchtri, horiz);
+    intersect = ONEDGE;
+  }
+  if (intersect == ONVERTEX) {
+    /* There's already a vertex there.  Return in `searchtri' a triangle */
+    /*   whose origin is the existing vertex.                            */
+    triedgecopy(horiz, *searchtri);
+    triedgecopy(horiz, recenttri);
+    return DUPLICATEPOINT;
+  }
+  if ((intersect == ONEDGE) || (intersect == OUTSIDE)) {
+    /* The vertex falls on an edge or boundary. */
+    if (checksegments && (splitedge == (struct edge *) NULL)) {
+      /* Check whether the vertex falls on a shell edge. */
+      tspivot(horiz, brokenshelle);
+      if (brokenshelle.sh != dummysh) {
+        /* The vertex falls on a shell edge. */
+        if (segmentflaws) {
+          if (nobisect == 0) {
+            /* Add the shell edge to the list of encroached segments. */
+            encroached = (struct edge *) poolalloc(&badsegments);
+            shellecopy(brokenshelle, *encroached);
+          } else if ((nobisect == 1) && (intersect == ONEDGE)) {
+            /* This segment may be split only if it is an internal boundary. */
+            sym(horiz, testtri);
+            if (testtri.tri != dummytri) {
+              /* Add the shell edge to the list of encroached segments. */
+              encroached = (struct edge *) poolalloc(&badsegments);
+              shellecopy(brokenshelle, *encroached);
+            }
+          }
+        }
+        /* Return a handle whose primary edge contains the point, */
+        /*   which has not been inserted.                         */
+        triedgecopy(horiz, *searchtri);
+        triedgecopy(horiz, recenttri);
+        return VIOLATINGPOINT;
+      }
+    }
+    /* Insert the point on an edge, dividing one triangle into two (if */
+    /*   the edge lies on a boundary) or two triangles into four.      */
+    lprev(horiz, botright);
+    sym(botright, botrcasing);
+    sym(horiz, topright);
+    /* Is there a second triangle?  (Or does this edge lie on a boundary?) */
+    mirrorflag = topright.tri != dummytri;
+    if (mirrorflag) {
+      lnextself(topright);
+      sym(topright, toprcasing);
+      maketriangle(&newtopright);
+    } else {
+      /* Splitting the boundary edge increases the number of boundary edges. */
+      hullsize++;
+    }
+    maketriangle(&newbotright);
+
+    /* Set the vertices of changed and new triangles. */
+    org(horiz, rightpoint);
+    dest(horiz, leftpoint);
+    apex(horiz, botpoint);
+    setorg(newbotright, botpoint);
+    setdest(newbotright, rightpoint);
+    setapex(newbotright, insertpoint);
+    setorg(horiz, insertpoint);
+    for (i = 0; i < eextras; i++) {
+      /* Set the element attributes of a new triangle. */
+      setelemattribute(newbotright, i, elemattribute(botright, i));
+    }
+    if (vararea) {
+      /* Set the area constraint of a new triangle. */
+      setareabound(newbotright, areabound(botright));
+    }
+    if (mirrorflag) {
+      dest(topright, toppoint);
+      setorg(newtopright, rightpoint);
+      setdest(newtopright, toppoint);
+      setapex(newtopright, insertpoint);
+      setorg(topright, insertpoint);
+      for (i = 0; i < eextras; i++) {
+        /* Set the element attributes of another new triangle. */
+        setelemattribute(newtopright, i, elemattribute(topright, i));
+      }
+      if (vararea) {
+        /* Set the area constraint of another new triangle. */
+        setareabound(newtopright, areabound(topright));
+      }
+    }
+
+    /* There may be shell edges that need to be bonded */
+    /*   to the new triangle(s).                       */
+    if (checksegments) {
+      tspivot(botright, botrshelle);
+      if (botrshelle.sh != dummysh) {
+        tsdissolve(botright);
+        tsbond(newbotright, botrshelle);
+      }
+      if (mirrorflag) {
+        tspivot(topright, toprshelle);
+        if (toprshelle.sh != dummysh) {
+          tsdissolve(topright);
+          tsbond(newtopright, toprshelle);
+        }
+      }
+    }
+
+    /* Bond the new triangle(s) to the surrounding triangles. */
+    bond(newbotright, botrcasing);
+    lprevself(newbotright);
+    bond(newbotright, botright);
+    lprevself(newbotright);
+    if (mirrorflag) {
+      bond(newtopright, toprcasing);
+      lnextself(newtopright);
+      bond(newtopright, topright);
+      lnextself(newtopright);
+      bond(newtopright, newbotright);
+    }
+
+    if (splitedge != (struct edge *) NULL) {
+      /* Split the shell edge into two. */
+      setsdest(*splitedge, insertpoint);
+      ssymself(*splitedge);
+      spivot(*splitedge, rightedge);
+      insertshelle(&newbotright, mark(*splitedge));
+      tspivot(newbotright, newedge);
+      sbond(*splitedge, newedge);
+      ssymself(newedge);
+      sbond(newedge, rightedge);
+      ssymself(*splitedge);
+    }
+
+#ifdef SELF_CHECK
+    if (counterclockwise(rightpoint, leftpoint, botpoint) < 0.0) {
+      printf("Internal error in insertsite():\n");
+      printf("  Clockwise triangle prior to edge point insertion (bottom).\n");
+    }
+    if (mirrorflag) {
+      if (counterclockwise(leftpoint, rightpoint, toppoint) < 0.0) {
+        printf("Internal error in insertsite():\n");
+        printf("  Clockwise triangle prior to edge point insertion (top).\n");
+      }
+      if (counterclockwise(rightpoint, toppoint, insertpoint) < 0.0) {
+        printf("Internal error in insertsite():\n");
+        printf("  Clockwise triangle after edge point insertion (top right).\n"
+               );
+      }
+      if (counterclockwise(toppoint, leftpoint, insertpoint) < 0.0) {
+        printf("Internal error in insertsite():\n");
+        printf("  Clockwise triangle after edge point insertion (top left).\n"
+               );
+      }
+    }
+    if (counterclockwise(leftpoint, botpoint, insertpoint) < 0.0) {
+      printf("Internal error in insertsite():\n");
+      printf("  Clockwise triangle after edge point insertion (bottom left).\n"
+             );
+    }
+    if (counterclockwise(botpoint, rightpoint, insertpoint) < 0.0) {
+      printf("Internal error in insertsite():\n");
+      printf(
+        "  Clockwise triangle after edge point insertion (bottom right).\n");
+    }
+#endif /* SELF_CHECK */
+    if (verbose > 2) {
+      printf("  Updating bottom left ");
+      printtriangle(&botright);
+      if (mirrorflag) {
+        printf("  Updating top left ");
+        printtriangle(&topright);
+        printf("  Creating top right ");
+        printtriangle(&newtopright);
+      }
+      printf("  Creating bottom right ");
+      printtriangle(&newbotright);
+    }
+
+    /* Position `horiz' on the first edge to check for */
+    /*   the Delaunay property.                        */
+    lnextself(horiz);
+  } else {
+    /* Insert the point in a triangle, splitting it into three. */
+    lnext(horiz, botleft);
+    lprev(horiz, botright);
+    sym(botleft, botlcasing);
+    sym(botright, botrcasing);
+    maketriangle(&newbotleft);
+    maketriangle(&newbotright);
+
+    /* Set the vertices of changed and new triangles. */
+    org(horiz, rightpoint);
+    dest(horiz, leftpoint);
+    apex(horiz, botpoint);
+    setorg(newbotleft, leftpoint);
+    setdest(newbotleft, botpoint);
+    setapex(newbotleft, insertpoint);
+    setorg(newbotright, botpoint);
+    setdest(newbotright, rightpoint);
+    setapex(newbotright, insertpoint);
+    setapex(horiz, insertpoint);
+    for (i = 0; i < eextras; i++) {
+      /* Set the element attributes of the new triangles. */
+      attrib = elemattribute(horiz, i);
+      setelemattribute(newbotleft, i, attrib);
+      setelemattribute(newbotright, i, attrib);
+    }
+    if (vararea) {
+      /* Set the area constraint of the new triangles. */
+      area = areabound(horiz);
+      setareabound(newbotleft, area);
+      setareabound(newbotright, area);
+    }
+
+    /* There may be shell edges that need to be bonded */
+    /*   to the new triangles.                         */
+    if (checksegments) {
+      tspivot(botleft, botlshelle);
+      if (botlshelle.sh != dummysh) {
+        tsdissolve(botleft);
+        tsbond(newbotleft, botlshelle);
+      }
+      tspivot(botright, botrshelle);
+      if (botrshelle.sh != dummysh) {
+        tsdissolve(botright);
+        tsbond(newbotright, botrshelle);
+      }
+    }
+
+    /* Bond the new triangles to the surrounding triangles. */
+    bond(newbotleft, botlcasing);
+    bond(newbotright, botrcasing);
+    lnextself(newbotleft);
+    lprevself(newbotright);
+    bond(newbotleft, newbotright);
+    lnextself(newbotleft);
+    bond(botleft, newbotleft);
+    lprevself(newbotright);
+    bond(botright, newbotright);
+
+#ifdef SELF_CHECK
+    if (counterclockwise(rightpoint, leftpoint, botpoint) < 0.0) {
+      printf("Internal error in insertsite():\n");
+      printf("  Clockwise triangle prior to point insertion.\n");
+    }
+    if (counterclockwise(rightpoint, leftpoint, insertpoint) < 0.0) {
+      printf("Internal error in insertsite():\n");
+      printf("  Clockwise triangle after point insertion (top).\n");
+    }
+    if (counterclockwise(leftpoint, botpoint, insertpoint) < 0.0) {
+      printf("Internal error in insertsite():\n");
+      printf("  Clockwise triangle after point insertion (left).\n");
+    }
+    if (counterclockwise(botpoint, rightpoint, insertpoint) < 0.0) {
+      printf("Internal error in insertsite():\n");
+      printf("  Clockwise triangle after point insertion (right).\n");
+    }
+#endif /* SELF_CHECK */
+    if (verbose > 2) {
+      printf("  Updating top ");
+      printtriangle(&horiz);
+      printf("  Creating left ");
+      printtriangle(&newbotleft);
+      printf("  Creating right ");
+      printtriangle(&newbotright);
+    }
+  }
+
+  /* The insertion is successful by default, unless an encroached */
+  /*   edge is found.                                             */
+  success = SUCCESSFULPOINT;
+  /* Circle around the newly inserted vertex, checking each edge opposite */
+  /*   it for the Delaunay property.  Non-Delaunay edges are flipped.     */
+  /*   `horiz' is always the edge being checked.  `first' marks where to  */
+  /*   stop circling.                                                     */
+  org(horiz, first);
+  rightpoint = first;
+  dest(horiz, leftpoint);
+  /* Circle until finished. */
+  while (1) {
+    /* By default, the edge will be flipped. */
+    doflip = 1;
+    if (checksegments) {
+      /* Check for a segment, which cannot be flipped. */
+      tspivot(horiz, checkshelle);
+      if (checkshelle.sh != dummysh) {
+        /* The edge is a segment and cannot be flipped. */
+        doflip = 0;
+#ifndef CDT_ONLY
+        if (segmentflaws) {
+          /* Does the new point encroach upon this segment? */
+          if (checkedge4encroach(&checkshelle)) {
+            success = ENCROACHINGPOINT;
+          }
+        }
+#endif /* not CDT_ONLY */
+      }
+    }
+    if (doflip) {
+      /* Check if the edge is a boundary edge. */
+      sym(horiz, top);
+      if (top.tri == dummytri) {
+        /* The edge is a boundary edge and cannot be flipped. */
+        doflip = 0;
+      } else {
+        /* Find the point on the other side of the edge. */
+        apex(top, farpoint);
+        /* In the incremental Delaunay triangulation algorithm, any of    */
+        /*   `leftpoint', `rightpoint', and `farpoint' could be vertices  */
+        /*   of the triangular bounding box.  These vertices must be      */
+        /*   treated as if they are infinitely distant, even though their */
+        /*   "coordinates" are not.                                       */
+        if ((leftpoint == infpoint1) || (leftpoint == infpoint2)
+                   || (leftpoint == infpoint3)) {
+          /* `leftpoint' is infinitely distant.  Check the convexity of */
+          /*   the boundary of the triangulation.  'farpoint' might be  */
+          /*   infinite as well, but trust me, this same condition      */
+          /*   should be applied.                                       */
+          doflip = counterclockwise(insertpoint, rightpoint, farpoint) > 0.0;
+        } else if ((rightpoint == infpoint1) || (rightpoint == infpoint2)
+                   || (rightpoint == infpoint3)) {
+          /* `rightpoint' is infinitely distant.  Check the convexity of */
+          /*   the boundary of the triangulation.  'farpoint' might be  */
+          /*   infinite as well, but trust me, this same condition      */
+          /*   should be applied.                                       */
+          doflip = counterclockwise(farpoint, leftpoint, insertpoint) > 0.0;
+        } else if ((farpoint == infpoint1) || (farpoint == infpoint2)
+            || (farpoint == infpoint3)) {
+          /* `farpoint' is infinitely distant and cannot be inside */
+          /*   the circumcircle of the triangle `horiz'.           */
+          doflip = 0;
+        } else {
+          /* Test whether the edge is locally Delaunay. */
+          doflip = incircle(leftpoint, insertpoint, rightpoint, farpoint)
+                   > 0.0;
+        }
+        if (doflip) {
+          /* We made it!  Flip the edge `horiz' by rotating its containing */
+          /*   quadrilateral (the two triangles adjacent to `horiz').      */
+          /* Identify the casing of the quadrilateral. */
+          lprev(top, topleft);
+          sym(topleft, toplcasing);
+          lnext(top, topright);
+          sym(topright, toprcasing);
+          lnext(horiz, botleft);
+          sym(botleft, botlcasing);
+          lprev(horiz, botright);
+          sym(botright, botrcasing);
+          /* Rotate the quadrilateral one-quarter turn counterclockwise. */
+          bond(topleft, botlcasing);
+          bond(botleft, botrcasing);
+          bond(botright, toprcasing);
+          bond(topright, toplcasing);
+          if (checksegments) {
+            /* Check for shell edges and rebond them to the quadrilateral. */
+            tspivot(topleft, toplshelle);
+            tspivot(botleft, botlshelle);
+            tspivot(botright, botrshelle);
+            tspivot(topright, toprshelle);
+            if (toplshelle.sh == dummysh) {
+              tsdissolve(topright);
+            } else {
+              tsbond(topright, toplshelle);
+            }
+            if (botlshelle.sh == dummysh) {
+              tsdissolve(topleft);
+            } else {
+              tsbond(topleft, botlshelle);
+            }
+            if (botrshelle.sh == dummysh) {
+              tsdissolve(botleft);
+            } else {
+              tsbond(botleft, botrshelle);
+            }
+            if (toprshelle.sh == dummysh) {
+              tsdissolve(botright);
+            } else {
+              tsbond(botright, toprshelle);
+            }
+          }
+          /* New point assignments for the rotated quadrilateral. */
+          setorg(horiz, farpoint);
+          setdest(horiz, insertpoint);
+          setapex(horiz, rightpoint);
+          setorg(top, insertpoint);
+          setdest(top, farpoint);
+          setapex(top, leftpoint);
+          for (i = 0; i < eextras; i++) {
+            /* Take the average of the two triangles' attributes. */
+            attrib = 0.5 * (elemattribute(top, i) + elemattribute(horiz, i));
+            setelemattribute(top, i, attrib);
+            setelemattribute(horiz, i, attrib);
+          }
+          if (vararea) {
+            if ((areabound(top) <= 0.0) || (areabound(horiz) <= 0.0)) {
+              area = -1.0;
+            } else {
+              /* Take the average of the two triangles' area constraints.    */
+              /*   This prevents small area constraints from migrating a     */
+              /*   long, long way from their original location due to flips. */
+              area = 0.5 * (areabound(top) + areabound(horiz));
+            }
+            setareabound(top, area);
+            setareabound(horiz, area);
+          }
+#ifdef SELF_CHECK
+          if (insertpoint != (point) NULL) {
+            if (counterclockwise(leftpoint, insertpoint, rightpoint) < 0.0) {
+              printf("Internal error in insertsite():\n");
+              printf("  Clockwise triangle prior to edge flip (bottom).\n");
+            }
+            /* The following test has been removed because constrainededge() */
+            /*   sometimes generates inverted triangles that insertsite()    */
+            /*   removes.                                                    */
+/*
+            if (counterclockwise(rightpoint, farpoint, leftpoint) < 0.0) {
+              printf("Internal error in insertsite():\n");
+              printf("  Clockwise triangle prior to edge flip (top).\n");
+            }
+*/
+            if (counterclockwise(farpoint, leftpoint, insertpoint) < 0.0) {
+              printf("Internal error in insertsite():\n");
+              printf("  Clockwise triangle after edge flip (left).\n");
+            }
+            if (counterclockwise(insertpoint, rightpoint, farpoint) < 0.0) {
+              printf("Internal error in insertsite():\n");
+              printf("  Clockwise triangle after edge flip (right).\n");
+            }
+          }
+#endif /* SELF_CHECK */
+          if (verbose > 2) {
+            printf("  Edge flip results in left ");
+            lnextself(topleft);
+            printtriangle(&topleft);
+            printf("  and right ");
+            printtriangle(&horiz);
+          }
+          /* On the next iterations, consider the two edges that were  */
+          /*   exposed (this is, are now visible to the newly inserted */
+          /*   point) by the edge flip.                                */
+          lprevself(horiz);
+          leftpoint = farpoint;
+        }
+      }
+    }
+    if (!doflip) {
+      /* The handle `horiz' is accepted as locally Delaunay. */
+#ifndef CDT_ONLY
+      if (triflaws) {
+        /* Check the triangle `horiz' for quality. */
+        testtriangle(&horiz);
+      }
+#endif /* not CDT_ONLY */
+      /* Look for the next edge around the newly inserted point. */
+      lnextself(horiz);
+      sym(horiz, testtri);
+      /* Check for finishing a complete revolution about the new point, or */
+      /*   falling off the edge of the triangulation.  The latter will     */
+      /*   happen when a point is inserted at a boundary.                  */
+      if ((leftpoint == first) || (testtri.tri == dummytri)) {
+        /* We're done.  Return a triangle whose origin is the new point. */
+        lnext(horiz, *searchtri);
+        lnext(horiz, recenttri);
+        return success;
+      }
+      /* Finish finding the next edge around the newly inserted point. */
+      lnext(testtri, horiz);
+      rightpoint = leftpoint;
+      dest(horiz, leftpoint);
+    }
+  }
+}
+
+/*****************************************************************************/
+/*                                                                           */
+/*  triangulatepolygon()   Find the Delaunay triangulation of a polygon that */
+/*                         has a certain "nice" shape.  This includes the    */
+/*                         polygons that result from deletion of a point or  */
+/*                         insertion of a segment.                           */
+/*                                                                           */
+/*  This is a conceptually difficult routine.  The starting assumption is    */
+/*  that we have a polygon with n sides.  n - 1 of these sides are currently */
+/*  represented as edges in the mesh.  One side, called the "base", need not */
+/*  be.                                                                      */
+/*                                                                           */
+/*  Inside the polygon is a structure I call a "fan", consisting of n - 1    */
+/*  triangles that share a common origin.  For each of these triangles, the  */
+/*  edge opposite the origin is one of the sides of the polygon.  The        */
+/*  primary edge of each triangle is the edge directed from the origin to    */
+/*  the destination; note that this is not the same edge that is a side of   */
+/*  the polygon.  `firstedge' is the primary edge of the first triangle.     */
+/*  From there, the triangles follow in counterclockwise order about the     */
+/*  polygon, until `lastedge', the primary edge of the last triangle.        */
+/*  `firstedge' and `lastedge' are probably connected to other triangles     */
+/*  beyond the extremes of the fan, but their identity is not important, as  */
+/*  long as the fan remains connected to them.                               */
+/*                                                                           */
+/*  Imagine the polygon oriented so that its base is at the bottom.  This    */
+/*  puts `firstedge' on the far right, and `lastedge' on the far left.       */
+/*  The right vertex of the base is the destination of `firstedge', and the  */
+/*  left vertex of the base is the apex of `lastedge'.                       */
+/*                                                                           */
+/*  The challenge now is to find the right sequence of edge flips to         */
+/*  transform the fan into a Delaunay triangulation of the polygon.  Each    */
+/*  edge flip effectively removes one triangle from the fan, committing it   */
+/*  to the polygon.  The resulting polygon has one fewer edge.  If `doflip'  */
+/*  is set, the final flip will be performed, resulting in a fan of one      */
+/*  (useless?) triangle.  If `doflip' is not set, the final flip is not      */
+/*  performed, resulting in a fan of two triangles, and an unfinished        */
+/*  triangular polygon that is not yet filled out with a single triangle.    */
+/*  On completion of the routine, `lastedge' is the last remaining triangle, */
+/*  or the leftmost of the last two.                                         */
+/*                                                                           */
+/*  Although the flips are performed in the order described above, the       */
+/*  decisions about what flips to perform are made in precisely the reverse  */
+/*  order.  The recursive triangulatepolygon() procedure makes a decision,   */
+/*  uses up to two recursive calls to triangulate the "subproblems"          */
+/*  (polygons with fewer edges), and then performs an edge flip.             */
+/*                                                                           */
+/*  The "decision" it makes is which vertex of the polygon should be         */
+/*  connected to the base.  This decision is made by testing every possible  */
+/*  vertex.  Once the best vertex is found, the two edges that connect this  */
+/*  vertex to the base become the bases for two smaller polygons.  These     */
+/*  are triangulated recursively.  Unfortunately, this approach can take     */
+/*  O(n^2) time not only in the worst case, but in many common cases.  It's  */
+/*  rarely a big deal for point deletion, where n is rarely larger than ten, */
+/*  but it could be a big deal for segment insertion, especially if there's  */
+/*  a lot of long segments that each cut many triangles.  I ought to code    */
+/*  a faster algorithm some time.                                            */
+/*                                                                           */
+/*  The `edgecount' parameter is the number of sides of the polygon,         */
+/*  including its base.  `triflaws' is a flag that determines whether the    */
+/*  new triangles should be tested for quality, and enqueued if they are     */
+/*  bad.                                                                     */
+/*                                                                           */
+/*****************************************************************************/
+
+void triangulatepolygon(firstedge, lastedge, edgecount, doflip, triflaws)
+struct triedge *firstedge;
+struct triedge *lastedge;
+int edgecount;
+int doflip;
+int triflaws;
+{
+  struct triedge testtri;
+  struct triedge besttri;
+  struct triedge tempedge;
+  point leftbasepoint, rightbasepoint;
+  point testpoint;
+  point bestpoint;
+  int bestnumber;
+  int i;
+  triangle ptr;   /* Temporary variable used by sym(), onext(), and oprev(). */
+
+  /* Identify the base vertices. */
+  apex(*lastedge, leftbasepoint);
+  dest(*firstedge, rightbasepoint);
+  if (verbose > 2) {
+    printf("  Triangulating interior polygon at edge\n");
+    printf("    (%.12g, %.12g) (%.12g, %.12g)\n", leftbasepoint[0],
+           leftbasepoint[1], rightbasepoint[0], rightbasepoint[1]);
+  }
+  /* Find the best vertex to connect the base to. */
+  onext(*firstedge, besttri);
+  dest(besttri, bestpoint);
+  triedgecopy(besttri, testtri);
+  bestnumber = 1;
+  for (i = 2; i <= edgecount - 2; i++) {
+    onextself(testtri);
+    dest(testtri, testpoint);
+    /* Is this a better vertex? */
+    if (incircle(leftbasepoint, rightbasepoint, bestpoint, testpoint) > 0.0) {
+      triedgecopy(testtri, besttri);
+      bestpoint = testpoint;
+      bestnumber = i;
+    }
+  }
+  if (verbose > 2) {
+    printf("    Connecting edge to (%.12g, %.12g)\n", bestpoint[0],
+           bestpoint[1]);
+  }
+  if (bestnumber > 1) {
+    /* Recursively triangulate the smaller polygon on the right. */
+    oprev(besttri, tempedge);
+    triangulatepolygon(firstedge, &tempedge, bestnumber + 1, 1, triflaws);
+  }
+  if (bestnumber < edgecount - 2) {
+    /* Recursively triangulate the smaller polygon on the left. */
+    sym(besttri, tempedge);
+    triangulatepolygon(&besttri, lastedge, edgecount - bestnumber, 1,
+                       triflaws);
+    /* Find `besttri' again; it may have been lost to edge flips. */
+    sym(tempedge, besttri);
+  }
+  if (doflip) {
+    /* Do one final edge flip. */
+    flip(&besttri);
+#ifndef CDT_ONLY
+    if (triflaws) {
+      /* Check the quality of the newly committed triangle. */
+      sym(besttri, testtri);
+      testtriangle(&testtri);
+    }
+#endif /* not CDT_ONLY */
+  }
+  /* Return the base triangle. */
+  triedgecopy(besttri, *lastedge);
+}
+
+/*****************************************************************************/
+/*                                                                           */
+/*  deletesite()   Delete a vertex from a Delaunay triangulation, ensuring   */
+/*                 that the triangulation remains Delaunay.                  */
+/*                                                                           */
+/*  The origin of `deltri' is deleted.  The union of the triangles adjacent  */
+/*  to this point is a polygon, for which the Delaunay triangulation is      */
+/*  found.  Two triangles are removed from the mesh.                         */
+/*                                                                           */
+/*  Only interior points that do not lie on segments (shell edges) or        */
+/*  boundaries may be deleted.                                               */
+/*                                                                           */
+/*****************************************************************************/
+
+#ifndef CDT_ONLY
+
+void deletesite(deltri)
+struct triedge *deltri;
+{
+  struct triedge countingtri;
+  struct triedge firstedge, lastedge;
+  struct triedge deltriright;
+  struct triedge lefttri, righttri;
+  struct triedge leftcasing, rightcasing;
+  struct edge leftshelle, rightshelle;
+  point delpoint;
+  point neworg;
+  int edgecount;
+  triangle ptr;   /* Temporary variable used by sym(), onext(), and oprev(). */
+  shelle sptr;                      /* Temporary variable used by tspivot(). */
+
+  org(*deltri, delpoint);
+  if (verbose > 1) {
+    printf("  Deleting (%.12g, %.12g).\n", delpoint[0], delpoint[1]);
+  }
+  pointdealloc(delpoint);
+
+  /* Count the degree of the point being deleted. */
+  onext(*deltri, countingtri);
+  edgecount = 1;
+  while (!triedgeequal(*deltri, countingtri)) {
+#ifdef SELF_CHECK
+    if (countingtri.tri == dummytri) {
+      printf("Internal error in deletesite():\n");
+      printf("  Attempt to delete boundary point.\n");
+      internalerror();
+    }
+#endif /* SELF_CHECK */
+    edgecount++;
+    onextself(countingtri);
+  }
+
+#ifdef SELF_CHECK
+  if (edgecount < 3) {
+    printf("Internal error in deletesite():\n  Point has degree %d.\n",
+           edgecount);
+    internalerror();
+  }
+#endif /* SELF_CHECK */
+  if (edgecount > 3) {
+    /* Triangulate the polygon defined by the union of all triangles */
+    /*   adjacent to the point being deleted.  Check the quality of  */
+    /*   the resulting triangles.                                    */
+    onext(*deltri, firstedge);
+    oprev(*deltri, lastedge);
+    triangulatepolygon(&firstedge, &lastedge, edgecount, 0, !nobisect);
+  }
+  /* Splice out two triangles. */
+  lprev(*deltri, deltriright);
+  dnext(*deltri, lefttri);
+  sym(lefttri, leftcasing);
+  oprev(deltriright, righttri);
+  sym(righttri, rightcasing);
+  bond(*deltri, leftcasing);
+  bond(deltriright, rightcasing);
+  tspivot(lefttri, leftshelle);
+  if (leftshelle.sh != dummysh) {
+    tsbond(*deltri, leftshelle);
+  }
+  tspivot(righttri, rightshelle);
+  if (rightshelle.sh != dummysh) {
+    tsbond(deltriright, rightshelle);
+  }
+
+  /* Set the new origin of `deltri' and check its quality. */
+  org(lefttri, neworg);
+  setorg(*deltri, neworg);
+  if (!nobisect) {
+    testtriangle(deltri);
+  }
+
+  /* Delete the two spliced-out triangles. */
+  triangledealloc(lefttri.tri);
+  triangledealloc(righttri.tri);
+}
+
+#endif /* not CDT_ONLY */
+
+/**                                                                         **/
+/**                                                                         **/
+/********* Mesh transformation routines end here                     *********/
+
+/********* Divide-and-conquer Delaunay triangulation begins here     *********/
+/**                                                                         **/
+/**                                                                         **/
+
+/*****************************************************************************/
+/*                                                                           */
+/*  The divide-and-conquer bounding box                                      */
+/*                                                                           */
+/*  I originally implemented the divide-and-conquer and incremental Delaunay */
+/*  triangulations using the edge-based data structure presented by Guibas   */
+/*  and Stolfi.  Switching to a triangle-based data structure doubled the    */
+/*  speed.  However, I had to think of a few extra tricks to maintain the    */
+/*  elegance of the original algorithms.                                     */
+/*                                                                           */
+/*  The "bounding box" used by my variant of the divide-and-conquer          */
+/*  algorithm uses one triangle for each edge of the convex hull of the      */
+/*  triangulation.  These bounding triangles all share a common apical       */
+/*  vertex, which is represented by NULL and which represents nothing.       */
+/*  The bounding triangles are linked in a circular fan about this NULL      */
+/*  vertex, and the edges on the convex hull of the triangulation appear     */
+/*  opposite the NULL vertex.  You might find it easiest to imagine that     */
+/*  the NULL vertex is a point in 3D space behind the center of the          */
+/*  triangulation, and that the bounding triangles form a sort of cone.      */
+/*                                                                           */
+/*  This bounding box makes it easy to represent degenerate cases.  For      */
+/*  instance, the triangulation of two vertices is a single edge.  This edge */
+/*  is represented by two bounding box triangles, one on each "side" of the  */
+/*  edge.  These triangles are also linked together in a fan about the NULL  */
+/*  vertex.                                                                  */
+/*                                                                           */
+/*  The bounding box also makes it easy to traverse the convex hull, as the  */
+/*  divide-and-conquer algorithm needs to do.                                */
+/*                                                                           */
+/*****************************************************************************/
+
+/*****************************************************************************/
+/*                                                                           */
+/*  pointsort()   Sort an array of points by x-coordinate, using the         */
+/*                y-coordinate as a secondary key.                           */
+/*                                                                           */
+/*  Uses quicksort.  Randomized O(n log n) time.  No, I did not make any of  */
+/*  the usual quicksort mistakes.                                            */
+/*                                                                           */
+/*****************************************************************************/
+
+void pointsort(sortarray, arraysize)
+point *sortarray;
+int arraysize;
+{
+  int left, right;
+  int pivot;
+  REAL pivotx, pivoty;
+  point temp;
+
+  if (arraysize == 2) {
+    /* Recursive base case. */
+    if ((sortarray[0][0] > sortarray[1][0]) ||
+        ((sortarray[0][0] == sortarray[1][0]) &&
+         (sortarray[0][1] > sortarray[1][1]))) {
+      temp = sortarray[1];
+      sortarray[1] = sortarray[0];
+      sortarray[0] = temp;
+    }
+    return;
+  }
+  /* Choose a random pivot to split the array. */
+  pivot = (int) randomnation(arraysize);
+  pivotx = sortarray[pivot][0];
+  pivoty = sortarray[pivot][1];
+  /* Split the array. */
+  left = -1;
+  right = arraysize;
+  while (left < right) {
+    /* Search for a point whose x-coordinate is too large for the left. */
+    do {
+      left++;
+    } while ((left <= right) && ((sortarray[left][0] < pivotx) ||
+                                 ((sortarray[left][0] == pivotx) &&
+                                  (sortarray[left][1] < pivoty))));
+    /* Search for a point whose x-coordinate is too small for the right. */
+    do {
+      right--;
+    } while ((left <= right) && ((sortarray[right][0] > pivotx) ||
+                                 ((sortarray[right][0] == pivotx) &&
+                                  (sortarray[right][1] > pivoty))));
+    if (left < right) {
+      /* Swap the left and right points. */
+      temp = sortarray[left];
+      sortarray[left] = sortarray[right];
+      sortarray[right] = temp;
+    }
+  }
+  if (left > 1) {
+    /* Recursively sort the left subset. */
+    pointsort(sortarray, left);
+  }
+  if (right < arraysize - 2) {
+    /* Recursively sort the right subset. */
+    pointsort(&sortarray[right + 1], arraysize - right - 1);
+  }
+}
+
+/*****************************************************************************/
+/*                                                                           */
+/*  pointmedian()   An order statistic algorithm, almost.  Shuffles an array */
+/*                  of points so that the first `median' points occur        */
+/*                  lexicographically before the remaining points.           */
+/*                                                                           */
+/*  Uses the x-coordinate as the primary key if axis == 0; the y-coordinate  */
+/*  if axis == 1.  Very similar to the pointsort() procedure, but runs in    */
+/*  randomized linear time.                                                  */
+/*                                                                           */
+/*****************************************************************************/
+
+void pointmedian(sortarray, arraysize, median, axis)
+point *sortarray;
+int arraysize;
+int median;
+int axis;
+{
+  int left, right;
+  int pivot;
+  REAL pivot1, pivot2;
+  point temp;
+
+  if (arraysize == 2) {
+    /* Recursive base case. */
+    if ((sortarray[0][axis] > sortarray[1][axis]) ||
+        ((sortarray[0][axis] == sortarray[1][axis]) &&
+         (sortarray[0][1 - axis] > sortarray[1][1 - axis]))) {
+      temp = sortarray[1];
+      sortarray[1] = sortarray[0];
+      sortarray[0] = temp;
+    }
+    return;
+  }
+  /* Choose a random pivot to split the array. */
+  pivot = (int) randomnation(arraysize);
+  pivot1 = sortarray[pivot][axis];
+  pivot2 = sortarray[pivot][1 - axis];
+  /* Split the array. */
+  left = -1;
+  right = arraysize;
+  while (left < right) {
+    /* Search for a point whose x-coordinate is too large for the left. */
+    do {
+      left++;
+    } while ((left <= right) && ((sortarray[left][axis] < pivot1) ||
+                                 ((sortarray[left][axis] == pivot1) &&
+                                  (sortarray[left][1 - axis] < pivot2))));
+    /* Search for a point whose x-coordinate is too small for the right. */
+    do {
+      right--;
+    } while ((left <= right) && ((sortarray[right][axis] > pivot1) ||
+                                 ((sortarray[right][axis] == pivot1) &&
+                                  (sortarray[right][1 - axis] > pivot2))));
+    if (left < right) {
+      /* Swap the left and right points. */
+      temp = sortarray[left];
+      sortarray[left] = sortarray[right];
+      sortarray[right] = temp;
+    }
+  }
+  /* Unlike in pointsort(), at most one of the following */
+  /*   conditionals is true.                             */
+  if (left > median) {
+    /* Recursively shuffle the left subset. */
+    pointmedian(sortarray, left, median, axis);
+  }
+  if (right < median - 1) {
+    /* Recursively shuffle the right subset. */
+    pointmedian(&sortarray[right + 1], arraysize - right - 1,
+                median - right - 1, axis);
+  }
+}
+
+/*****************************************************************************/
+/*                                                                           */
+/*  alternateaxes()   Sorts the points as appropriate for the divide-and-    */
+/*                    conquer algorithm with alternating cuts.               */
+/*                                                                           */
+/*  Partitions by x-coordinate if axis == 0; by y-coordinate if axis == 1.   */
+/*  For the base case, subsets containing only two or three points are       */
+/*  always sorted by x-coordinate.                                           */
+/*                                                                           */
+/*****************************************************************************/
+
+void alternateaxes(sortarray, arraysize, axis)
+point *sortarray;
+int arraysize;
+int axis;
+{
+  int divider;
+
+  divider = arraysize >> 1;
+  if (arraysize <= 3) {
+    /* Recursive base case:  subsets of two or three points will be      */
+    /*   handled specially, and should always be sorted by x-coordinate. */
+    axis = 0;
+  }
+  /* Partition with a horizontal or vertical cut. */
+  pointmedian(sortarray, arraysize, divider, axis);
+  /* Recursively partition the subsets with a cross cut. */
+  if (arraysize - divider >= 2) {
+    if (divider >= 2) {
+      alternateaxes(sortarray, divider, 1 - axis);
+    }
+    alternateaxes(&sortarray[divider], arraysize - divider, 1 - axis);
+  }
+}
+
+/*****************************************************************************/
+/*                                                                           */
+/*  mergehulls()   Merge two adjacent Delaunay triangulations into a         */
+/*                 single Delaunay triangulation.                            */
+/*                                                                           */
+/*  This is similar to the algorithm given by Guibas and Stolfi, but uses    */
+/*  a triangle-based, rather than edge-based, data structure.                */
+/*                                                                           */
+/*  The algorithm walks up the gap between the two triangulations, knitting  */
+/*  them together.  As they are merged, some of their bounding triangles     */
+/*  are converted into real triangles of the triangulation.  The procedure   */
+/*  pulls each hull's bounding triangles apart, then knits them together     */
+/*  like the teeth of two gears.  The Delaunay property determines, at each  */
+/*  step, whether the next "tooth" is a bounding triangle of the left hull   */
+/*  or the right.  When a bounding triangle becomes real, its apex is        */
+/*  changed from NULL to a real point.                                       */
+/*                                                                           */
+/*  Only two new triangles need to be allocated.  These become new bounding  */
+/*  triangles at the top and bottom of the seam.  They are used to connect   */
+/*  the remaining bounding triangles (those that have not been converted     */
+/*  into real triangles) into a single fan.                                  */
+/*                                                                           */
+/*  On entry, `farleft' and `innerleft' are bounding triangles of the left   */
+/*  triangulation.  The origin of `farleft' is the leftmost vertex, and      */
+/*  the destination of `innerleft' is the rightmost vertex of the            */
+/*  triangulation.  Similarly, `innerright' and `farright' are bounding      */
+/*  triangles of the right triangulation.  The origin of `innerright' and    */
+/*  destination of `farright' are the leftmost and rightmost vertices.       */
+/*                                                                           */
+/*  On completion, the origin of `farleft' is the leftmost vertex of the     */
+/*  merged triangulation, and the destination of `farright' is the rightmost */
+/*  vertex.                                                                  */
+/*                                                                           */
+/*****************************************************************************/
+
+void mergehulls(farleft, innerleft, innerright, farright, axis)
+struct triedge *farleft;
+struct triedge *innerleft;
+struct triedge *innerright;
+struct triedge *farright;
+int axis;
+{
+  struct triedge leftcand, rightcand;
+  struct triedge baseedge;
+  struct triedge nextedge;
+  struct triedge sidecasing, topcasing, outercasing;
+  struct triedge checkedge;
+  point innerleftdest;
+  point innerrightorg;
+  point innerleftapex, innerrightapex;
+  point farleftpt, farrightpt;
+  point farleftapex, farrightapex;
+  point lowerleft, lowerright;
+  point upperleft, upperright;
+  point nextapex;
+  point checkvertex;
+  int changemade;
+  int badedge;
+  int leftfinished, rightfinished;
+  triangle ptr;                         /* Temporary variable used by sym(). */
+
+  dest(*innerleft, innerleftdest);
+  apex(*innerleft, innerleftapex);
+  org(*innerright, innerrightorg);
+  apex(*innerright, innerrightapex);
+  /* Special treatment for horizontal cuts. */
+  if (dwyer && (axis == 1)) {
+    org(*farleft, farleftpt);
+    apex(*farleft, farleftapex);
+    dest(*farright, farrightpt);
+    apex(*farright, farrightapex);
+    /* The pointers to the extremal points are shifted to point to the */
+    /*   topmost and bottommost point of each hull, rather than the    */
+    /*   leftmost and rightmost points.                                */
+    while (farleftapex[1] < farleftpt[1]) {
+      lnextself(*farleft);
+      symself(*farleft);
+      farleftpt = farleftapex;
+      apex(*farleft, farleftapex);
+    }
+    sym(*innerleft, checkedge);
+    apex(checkedge, checkvertex);
+    while (checkvertex[1] > innerleftdest[1]) {
+      lnext(checkedge, *innerleft);
+      innerleftapex = innerleftdest;
+      innerleftdest = checkvertex;
+      sym(*innerleft, checkedge);
+      apex(checkedge, checkvertex);
+    }
+    while (innerrightapex[1] < innerrightorg[1]) {
+      lnextself(*innerright);
+      symself(*innerright);
+      innerrightorg = innerrightapex;
+      apex(*innerright, innerrightapex);
+    }
+    sym(*farright, checkedge);
+    apex(checkedge, checkvertex);
+    while (checkvertex[1] > farrightpt[1]) {
+      lnext(checkedge, *farright);
+      farrightapex = farrightpt;
+      farrightpt = checkvertex;
+      sym(*farright, checkedge);
+      apex(checkedge, checkvertex);
+    }
+  }
+  /* Find a line tangent to and below both hulls. */
+  do {
+    changemade = 0;
+    /* Make innerleftdest the "bottommost" point of the left hull. */
+    if (counterclockwise(innerleftdest, innerleftapex, innerrightorg) > 0.0) {
+      lprevself(*innerleft);
+      symself(*innerleft);
+      innerleftdest = innerleftapex;
+      apex(*innerleft, innerleftapex);
+      changemade = 1;
+    }
+    /* Make innerrightorg the "bottommost" point of the right hull. */
+    if (counterclockwise(innerrightapex, innerrightorg, innerleftdest) > 0.0) {
+      lnextself(*innerright);
+      symself(*innerright);
+      innerrightorg = innerrightapex;
+      apex(*innerright, innerrightapex);
+      changemade = 1;
+    }
+  } while (changemade);
+  /* Find the two candidates to be the next "gear tooth". */
+  sym(*innerleft, leftcand);
+  sym(*innerright, rightcand);
+  /* Create the bottom new bounding triangle. */
+  maketriangle(&baseedge);
+  /* Connect it to the bounding boxes of the left and right triangulations. */
+  bond(baseedge, *innerleft);
+  lnextself(baseedge);
+  bond(baseedge, *innerright);
+  lnextself(baseedge);
+  setorg(baseedge, innerrightorg);
+  setdest(baseedge, innerleftdest);
+  /* Apex is intentionally left NULL. */
+  if (verbose > 2) {
+    printf("  Creating base bounding ");
+    printtriangle(&baseedge);
+  }
+  /* Fix the extreme triangles if necessary. */
+  org(*farleft, farleftpt);
+  if (innerleftdest == farleftpt) {
+    lnext(baseedge, *farleft);
+  }
+  dest(*farright, farrightpt);
+  if (innerrightorg == farrightpt) {
+    lprev(baseedge, *farright);
+  }
+  /* The vertices of the current knitting edge. */
+  lowerleft = innerleftdest;
+  lowerright = innerrightorg;
+  /* The candidate vertices for knitting. */
+  apex(leftcand, upperleft);
+  apex(rightcand, upperright);
+  /* Walk up the gap between the two triangulations, knitting them together. */
+  while (1) {
+    /* Have we reached the top?  (This isn't quite the right question,       */
+    /*   because even though the left triangulation might seem finished now, */
+    /*   moving up on the right triangulation might reveal a new point of    */
+    /*   the left triangulation.  And vice-versa.)                           */
+    leftfinished = counterclockwise(upperleft, lowerleft, lowerright) <= 0.0;
+    rightfinished = counterclockwise(upperright, lowerleft, lowerright) <= 0.0;
+    if (leftfinished && rightfinished) {
+      /* Create the top new bounding triangle. */
+      maketriangle(&nextedge);
+      setorg(nextedge, lowerleft);
+      setdest(nextedge, lowerright);
+      /* Apex is intentionally left NULL. */
+      /* Connect it to the bounding boxes of the two triangulations. */
+      bond(nextedge, baseedge);
+      lnextself(nextedge);
+      bond(nextedge, rightcand);
+      lnextself(nextedge);
+      bond(nextedge, leftcand);
+      if (verbose > 2) {
+        printf("  Creating top bounding ");
+        printtriangle(&baseedge);
+      }
+      /* Special treatment for horizontal cuts. */
+      if (dwyer && (axis == 1)) {
+        org(*farleft, farleftpt);
+        apex(*farleft, farleftapex);
+        dest(*farright, farrightpt);
+        apex(*farright, farrightapex);
+        sym(*farleft, checkedge);
+        apex(checkedge, checkvertex);
+        /* The pointers to the extremal points are restored to the leftmost */
+        /*   and rightmost points (rather than topmost and bottommost).     */
+        while (checkvertex[0] < farleftpt[0]) {
+          lprev(checkedge, *farleft);
+          farleftapex = farleftpt;
+          farleftpt = checkvertex;
+          sym(*farleft, checkedge);
+          apex(checkedge, checkvertex);
+        }
+        while (farrightapex[0] > farrightpt[0]) {
+          lprevself(*farright);
+          symself(*farright);
+          farrightpt = farrightapex;
+          apex(*farright, farrightapex);
+        }
+      }
+      return;
+    }
+    /* Consider eliminating edges from the left triangulation. */
+    if (!leftfinished) {
+      /* What vertex would be exposed if an edge were deleted? */
+      lprev(leftcand, nextedge);
+      symself(nextedge);
+      apex(nextedge, nextapex);
+      /* If nextapex is NULL, then no vertex would be exposed; the */
+      /*   triangulation would have been eaten right through.      */
+      if (nextapex != (point) NULL) {
+        /* Check whether the edge is Delaunay. */
+        badedge = incircle(lowerleft, lowerright, upperleft, nextapex) > 0.0;
+        while (badedge) {
+          /* Eliminate the edge with an edge flip.  As a result, the    */
+          /*   left triangulation will have one more boundary triangle. */
+          lnextself(nextedge);
+          sym(nextedge, topcasing);
+          lnextself(nextedge);
+          sym(nextedge, sidecasing);
+          bond(nextedge, topcasing);
+          bond(leftcand, sidecasing);
+          lnextself(leftcand);
+          sym(leftcand, outercasing);
+          lprevself(nextedge);
+          bond(nextedge, outercasing);
+          /* Correct the vertices to reflect the edge flip. */
+          setorg(leftcand, lowerleft);
+          setdest(leftcand, NULL);
+          setapex(leftcand, nextapex);
+          setorg(nextedge, NULL);
+          setdest(nextedge, upperleft);
+          setapex(nextedge, nextapex);
+          /* Consider the newly exposed vertex. */
+          upperleft = nextapex;
+          /* What vertex would be exposed if another edge were deleted? */
+          triedgecopy(sidecasing, nextedge);
+          apex(nextedge, nextapex);
+          if (nextapex != (point) NULL) {
+            /* Check whether the edge is Delaunay. */
+            badedge = incircle(lowerleft, lowerright, upperleft, nextapex)
+                      > 0.0;
+          } else {
+            /* Avoid eating right through the triangulation. */
+            badedge = 0;
+          }
+        }
+      }
+    }
+    /* Consider eliminating edges from the right triangulation. */
+    if (!rightfinished) {
+      /* What vertex would be exposed if an edge were deleted? */
+      lnext(rightcand, nextedge);
+      symself(nextedge);
+      apex(nextedge, nextapex);
+      /* If nextapex is NULL, then no vertex would be exposed; the */
+      /*   triangulation would have been eaten right through.      */
+      if (nextapex != (point) NULL) {
+        /* Check whether the edge is Delaunay. */
+        badedge = incircle(lowerleft, lowerright, upperright, nextapex) > 0.0;
+        while (badedge) {
+          /* Eliminate the edge with an edge flip.  As a result, the     */
+          /*   right triangulation will have one more boundary triangle. */
+          lprevself(nextedge);
+          sym(nextedge, topcasing);
+          lprevself(nextedge);
+          sym(nextedge, sidecasing);
+          bond(nextedge, topcasing);
+          bond(rightcand, sidecasing);
+          lprevself(rightcand);
+          sym(rightcand, outercasing);
+          lnextself(nextedge);
+          bond(nextedge, outercasing);
+          /* Correct the vertices to reflect the edge flip. */
+          setorg(rightcand, NULL);
+          setdest(rightcand, lowerright);
+          setapex(rightcand, nextapex);
+          setorg(nextedge, upperright);
+          setdest(nextedge, NULL);
+          setapex(nextedge, nextapex);
+          /* Consider the newly exposed vertex. */
+          upperright = nextapex;
+          /* What vertex would be exposed if another edge were deleted? */
+          triedgecopy(sidecasing, nextedge);
+          apex(nextedge, nextapex);
+          if (nextapex != (point) NULL) {
+            /* Check whether the edge is Delaunay. */
+            badedge = incircle(lowerleft, lowerright, upperright, nextapex)
+                      > 0.0;
+          } else {
+            /* Avoid eating right through the triangulation. */
+            badedge = 0;
+          }
+        }
+      }
+    }
+    if (leftfinished || (!rightfinished &&
+           (incircle(upperleft, lowerleft, lowerright, upperright) > 0.0))) {
+      /* Knit the triangulations, adding an edge from `lowerleft' */
+      /*   to `upperright'.                                       */
+      bond(baseedge, rightcand);
+      lprev(rightcand, baseedge);
+      setdest(baseedge, lowerleft);
+      lowerright = upperright;
+      sym(baseedge, rightcand);
+      apex(rightcand, upperright);
+    } else {
+      /* Knit the triangulations, adding an edge from `upperleft' */
+      /*   to `lowerright'.                                       */
+      bond(baseedge, leftcand);
+      lnext(leftcand, baseedge);
+      setorg(baseedge, lowerright);
+      lowerleft = upperleft;
+      sym(baseedge, leftcand);
+      apex(leftcand, upperleft);
+    }
+    if (verbose > 2) {
+      printf("  Connecting ");
+      printtriangle(&baseedge);
+    }
+  }
+}
+
+/*****************************************************************************/
+/*                                                                           */
+/*  divconqrecurse()   Recursively form a Delaunay triangulation by the      */
+/*                     divide-and-conquer method.                            */
+/*                                                                           */
+/*  Recursively breaks down the problem into smaller pieces, which are       */
+/*  knitted together by mergehulls().  The base cases (problems of two or    */
+/*  three points) are handled specially here.                                */
+/*                                                                           */
+/*  On completion, `farleft' and `farright' are bounding triangles such that */
+/*  the origin of `farleft' is the leftmost vertex (breaking ties by         */
+/*  choosing the highest leftmost vertex), and the destination of            */
+/*  `farright' is the rightmost vertex (breaking ties by choosing the        */
+/*  lowest rightmost vertex).                                                */
+/*                                                                           */
+/*****************************************************************************/
+
+void divconqrecurse(sortarray, vertices, axis, farleft, farright)
+point *sortarray;
+int vertices;
+int axis;
+struct triedge *farleft;
+struct triedge *farright;
+{
+  struct triedge midtri, tri1, tri2, tri3;
+  struct triedge innerleft, innerright;
+  REAL area;
+  int divider;
+
+  if (verbose > 2) {
+    printf("  Triangulating %d points.\n", vertices);
+  }
+  if (vertices == 2) {
+    /* The triangulation of two vertices is an edge.  An edge is */
+    /*   represented by two bounding triangles.                  */
+    maketriangle(farleft);
+    setorg(*farleft, sortarray[0]);
+    setdest(*farleft, sortarray[1]);
+    /* The apex is intentionally left NULL. */
+    maketriangle(farright);
+    setorg(*farright, sortarray[1]);
+    setdest(*farright, sortarray[0]);
+    /* The apex is intentionally left NULL. */
+    bond(*farleft, *farright);
+    lprevself(*farleft);
+    lnextself(*farright);
+    bond(*farleft, *farright);
+    lprevself(*farleft);
+    lnextself(*farright);
+    bond(*farleft, *farright);
+    if (verbose > 2) {
+      printf("  Creating ");
+      printtriangle(farleft);
+      printf("  Creating ");
+      printtriangle(farright);
+    }
+    /* Ensure that the origin of `farleft' is sortarray[0]. */
+    lprev(*farright, *farleft);
+    return;
+  } else if (vertices == 3) {
+    /* The triangulation of three vertices is either a triangle (with */
+    /*   three bounding triangles) or two edges (with four bounding   */
+    /*   triangles).  In either case, four triangles are created.     */
+    maketriangle(&midtri);
+    maketriangle(&tri1);
+    maketriangle(&tri2);
+    maketriangle(&tri3);
+    area = counterclockwise(sortarray[0], sortarray[1], sortarray[2]);
+    if (area == 0.0) {
+      /* Three collinear points; the triangulation is two edges. */
+      setorg(midtri, sortarray[0]);
+      setdest(midtri, sortarray[1]);
+      setorg(tri1, sortarray[1]);
+      setdest(tri1, sortarray[0]);
+      setorg(tri2, sortarray[2]);
+      setdest(tri2, sortarray[1]);
+      setorg(tri3, sortarray[1]);
+      setdest(tri3, sortarray[2]);
+      /* All apices are intentionally left NULL. */
+      bond(midtri, tri1);
+      bond(tri2, tri3);
+      lnextself(midtri);
+      lprevself(tri1);
+      lnextself(tri2);
+      lprevself(tri3);
+      bond(midtri, tri3);
+      bond(tri1, tri2);
+      lnextself(midtri);
+      lprevself(tri1);
+      lnextself(tri2);
+      lprevself(tri3);
+      bond(midtri, tri1);
+      bond(tri2, tri3);
+      /* Ensure that the origin of `farleft' is sortarray[0]. */
+      triedgecopy(tri1, *farleft);
+      /* Ensure that the destination of `farright' is sortarray[2]. */
+      triedgecopy(tri2, *farright);
+    } else {
+      /* The three points are not collinear; the triangulation is one */
+      /*   triangle, namely `midtri'.                                 */
+      setorg(midtri, sortarray[0]);
+      setdest(tri1, sortarray[0]);
+      setorg(tri3, sortarray[0]);
+      /* Apices of tri1, tri2, and tri3 are left NULL. */
+      if (area > 0.0) {
+        /* The vertices are in counterclockwise order. */
+        setdest(midtri, sortarray[1]);
+        setorg(tri1, sortarray[1]);
+        setdest(tri2, sortarray[1]);
+        setapex(midtri, sortarray[2]);
+        setorg(tri2, sortarray[2]);
+        setdest(tri3, sortarray[2]);
+      } else {
+        /* The vertices are in clockwise order. */
+        setdest(midtri, sortarray[2]);
+        setorg(tri1, sortarray[2]);
+        setdest(tri2, sortarray[2]);
+        setapex(midtri, sortarray[1]);
+        setorg(tri2, sortarray[1]);
+        setdest(tri3, sortarray[1]);
+      }
+      /* The topology does not depend on how the vertices are ordered. */
+      bond(midtri, tri1);
+      lnextself(midtri);
+      bond(midtri, tri2);
+      lnextself(midtri);
+      bond(midtri, tri3);
+      lprevself(tri1);
+      lnextself(tri2);
+      bond(tri1, tri2);
+      lprevself(tri1);
+      lprevself(tri3);
+      bond(tri1, tri3);
+      lnextself(tri2);
+      lprevself(tri3);
+      bond(tri2, tri3);
+      /* Ensure that the origin of `farleft' is sortarray[0]. */
+      triedgecopy(tri1, *farleft);
+      /* Ensure that the destination of `farright' is sortarray[2]. */
+      if (area > 0.0) {
+        triedgecopy(tri2, *farright);
+      } else {
+        lnext(*farleft, *farright);
+      }
+    }
+    if (verbose > 2) {
+      printf("  Creating ");
+      printtriangle(&midtri);
+      printf("  Creating ");
+      printtriangle(&tri1);
+      printf("  Creating ");
+      printtriangle(&tri2);
+      printf("  Creating ");
+      printtriangle(&tri3);
+    }
+    return;
+  } else {
+    /* Split the vertices in half. */
+    divider = vertices >> 1;
+    /* Recursively triangulate each half. */
+    divconqrecurse(sortarray, divider, 1 - axis, farleft, &innerleft);
+    divconqrecurse(&sortarray[divider], vertices - divider, 1 - axis,
+                   &innerright, farright);
+    if (verbose > 1) {
+      printf("  Joining triangulations with %d and %d vertices.\n", divider,
+             vertices - divider);
+    }
+    /* Merge the two triangulations into one. */
+    mergehulls(farleft, &innerleft, &innerright, farright, axis);
+  }
+}
+
+long removeghosts(startghost)
+struct triedge *startghost;
+{
+  struct triedge searchedge;
+  struct triedge dissolveedge;
+  struct triedge deadtri;
+  point markorg;
+  long hullsize;
+  triangle ptr;                         /* Temporary variable used by sym(). */
+
+  if (verbose) {
+    printf("  Removing ghost triangles.\n");
+  }
+  /* Find an edge on the convex hull to start point location from. */
+  lprev(*startghost, searchedge);
+  symself(searchedge);
+  dummytri[0] = encode(searchedge);
+  /* Remove the bounding box and count the convex hull edges. */
+  triedgecopy(*startghost, dissolveedge);
+  hullsize = 0;
+  do {
+    hullsize++;
+    lnext(dissolveedge, deadtri);
+    lprevself(dissolveedge);
+    symself(dissolveedge);
+    /* If no PSLG is involved, set the boundary markers of all the points */
+    /*   on the convex hull.  If a PSLG is used, this step is done later. */
+    if (!poly) {
+      /* Watch out for the case where all the input points are collinear. */
+      if (dissolveedge.tri != dummytri) {
+        org(dissolveedge, markorg);
+        if (pointmark(markorg) == 0) {
+          setpointmark(markorg, 1);
+        }
+      }
+    }
+    /* Remove a bounding triangle from a convex hull triangle. */
+    dissolve(dissolveedge);
+    /* Find the next bounding triangle. */
+    sym(deadtri, dissolveedge);
+    /* Delete the bounding triangle. */
+    triangledealloc(deadtri.tri);
+  } while (!triedgeequal(dissolveedge, *startghost));
+  return hullsize;
+}
+
+/*****************************************************************************/
+/*                                                                           */
+/*  divconqdelaunay()   Form a Delaunay triangulation by the divide-and-     */
+/*                      conquer method.                                      */
+/*                                                                           */
+/*  Sorts the points, calls a recursive procedure to triangulate them, and   */
+/*  removes the bounding box, setting boundary markers as appropriate.       */
+/*                                                                           */
+/*****************************************************************************/
+
+long divconqdelaunay()
+{
+  point *sortarray;
+  struct triedge hullleft, hullright;
+  int divider;
+  int i, j;
+
+  /* Allocate an array of pointers to points for sorting. */
+  sortarray = (point *) malloc(inpoints * sizeof(point));
+  if (sortarray == (point *) NULL) {
+    printf("Error:  Out of memory.\n");
+    exit(1);
+  }
+  traversalinit(&points);
+  for (i = 0; i < inpoints; i++) {
+    sortarray[i] = pointtraverse();
+  }
+  if (verbose) {
+    printf("  Sorting points.\n");
+  }
+  /* Sort the points. */
+  pointsort(sortarray, inpoints);
+  /* Discard duplicate points, which can really mess up the algorithm. */
+  i = 0;
+  for (j = 1; j < inpoints; j++) {
+    if ((sortarray[i][0] == sortarray[j][0])
+        && (sortarray[i][1] == sortarray[j][1])) {
+      if (!quiet) {
+        printf(
+"Warning:  A duplicate point at (%.12g, %.12g) appeared and was ignored.\n",
+               sortarray[j][0], sortarray[j][1]);
+      }
+/*  Commented out - would eliminate point from output .node file, but causes
+    a failure if some segment has this point as an endpoint.
+      setpointmark(sortarray[j], DEADPOINT);
+*/
+    } else {
+      i++;
+      sortarray[i] = sortarray[j];
+    }
+  }
+  i++;
+  if (dwyer) {
+    /* Re-sort the array of points to accommodate alternating cuts. */
+    divider = i >> 1;
+    if (i - divider >= 2) {
+      if (divider >= 2) {
+        alternateaxes(sortarray, divider, 1);
+      }
+      alternateaxes(&sortarray[divider], i - divider, 1);
+    }
+  }
+  if (verbose) {
+    printf("  Forming triangulation.\n");
+  }
+  /* Form the Delaunay triangulation. */
+  divconqrecurse(sortarray, i, 0, &hullleft, &hullright);
+  free(sortarray);
+
+  return removeghosts(&hullleft);
+}
+
+/**                                                                         **/
+/**                                                                         **/
+/********* Divide-and-conquer Delaunay triangulation ends here       *********/
+
+/********* Incremental Delaunay triangulation begins here            *********/
+/**                                                                         **/
+/**                                                                         **/
+
+/*****************************************************************************/
+/*                                                                           */
+/*  boundingbox()   Form an "infinite" bounding triangle to insert points    */
+/*                  into.                                                    */
+/*                                                                           */
+/*  The points at "infinity" are assigned finite coordinates, which are used */
+/*  by the point location routines, but (mostly) ignored by the Delaunay     */
+/*  edge flip routines.                                                      */
+/*                                                                           */
+/*****************************************************************************/
+
+#ifndef REDUCED
+
+void boundingbox()
+{
+  struct triedge inftri;          /* Handle for the triangular bounding box. */
+  REAL width;
+
+  if (verbose) {
+    printf("  Creating triangular bounding box.\n");
+  }
+  /* Find the width (or height, whichever is larger) of the triangulation. */
+  width = xmax - xmin;
+  if (ymax - ymin > width) {
+    width = ymax - ymin;
+  }
+  if (width == 0.0) {
+    width = 1.0;
+  }
+  /* Create the vertices of the bounding box. */
+  infpoint1 = (point) malloc(points.itembytes);
+  infpoint2 = (point) malloc(points.itembytes);
+  infpoint3 = (point) malloc(points.itembytes);
+  if ((infpoint1 == (point) NULL) || (infpoint2 == (point) NULL)
+      || (infpoint3 == (point) NULL)) {
+    printf("Error:  Out of memory.\n");
+    exit(1);
+  }
+  infpoint1[0] = xmin - 50.0 * width;
+  infpoint1[1] = ymin - 40.0 * width;
+  infpoint2[0] = xmax + 50.0 * width;
+  infpoint2[1] = ymin - 40.0 * width;
+  infpoint3[0] = 0.5 * (xmin + xmax);
+  infpoint3[1] = ymax + 60.0 * width;
+
+  /* Create the bounding box. */
+  maketriangle(&inftri);
+  setorg(inftri, infpoint1);
+  setdest(inftri, infpoint2);
+  setapex(inftri, infpoint3);
+  /* Link dummytri to the bounding box so we can always find an */
+  /*   edge to begin searching (point location) from.           */
+  dummytri[0] = (triangle) inftri.tri;
+  if (verbose > 2) {
+    printf("  Creating ");
+    printtriangle(&inftri);
+  }
+}
+
+#endif /* not REDUCED */
+
+/*****************************************************************************/
+/*                                                                           */
+/*  removebox()   Remove the "infinite" bounding triangle, setting boundary  */
+/*                markers as appropriate.                                    */
+/*                                                                           */
+/*  The triangular bounding box has three boundary triangles (one for each   */
+/*  side of the bounding box), and a bunch of triangles fanning out from     */
+/*  the three bounding box vertices (one triangle for each edge of the       */
+/*  convex hull of the inner mesh).  This routine removes these triangles.   */
+/*                                                                           */
+/*****************************************************************************/
+
+#ifndef REDUCED
+
+long removebox()
+{
+  struct triedge deadtri;
+  struct triedge searchedge;
+  struct triedge checkedge;
+  struct triedge nextedge, finaledge, dissolveedge;
+  point markorg;
+  long hullsize;
+  triangle ptr;                         /* Temporary variable used by sym(). */
+
+  if (verbose) {
+    printf("  Removing triangular bounding box.\n");
+  }
+  /* Find a boundary triangle. */
+  nextedge.tri = dummytri;
+  nextedge.orient = 0;
+  symself(nextedge);
+  /* Mark a place to stop. */
+  lprev(nextedge, finaledge);
+  lnextself(nextedge);
+  symself(nextedge);
+  /* Find a triangle (on the boundary of the point set) that isn't */
+  /*   a bounding box triangle.                                    */
+  lprev(nextedge, searchedge);
+  symself(searchedge);
+  /* Check whether nextedge is another boundary triangle */
+  /*   adjacent to the first one.                        */
+  lnext(nextedge, checkedge);
+  symself(checkedge);
+  if (checkedge.tri == dummytri) {
+    /* Go on to the next triangle.  There are only three boundary   */
+    /*   triangles, and this next triangle cannot be the third one, */
+    /*   so it's safe to stop here.                                 */
+    lprevself(searchedge);
+    symself(searchedge);
+  }
+  /* Find a new boundary edge to search from, as the current search */
+  /*   edge lies on a bounding box triangle and will be deleted.    */
+  dummytri[0] = encode(searchedge);
+  hullsize = -2l;
+  while (!triedgeequal(nextedge, finaledge)) {
+    hullsize++;
+    lprev(nextedge, dissolveedge);
+    symself(dissolveedge);
+    /* If not using a PSLG, the vertices should be marked now. */
+    /*   (If using a PSLG, markhull() will do the job.)        */
+    if (!poly) {
+      /* Be careful!  One must check for the case where all the input   */
+      /*   points are collinear, and thus all the triangles are part of */
+      /*   the bounding box.  Otherwise, the setpointmark() call below  */
+      /*   will cause a bad pointer reference.                          */
+      if (dissolveedge.tri != dummytri) {
+        org(dissolveedge, markorg);
+        if (pointmark(markorg) == 0) {
+          setpointmark(markorg, 1);
+        }
+      }
+    }
+    /* Disconnect the bounding box triangle from the mesh triangle. */
+    dissolve(dissolveedge);
+    lnext(nextedge, deadtri);
+    sym(deadtri, nextedge);
+    /* Get rid of the bounding box triangle. */
+    triangledealloc(deadtri.tri);
+    /* Do we need to turn the corner? */
+    if (nextedge.tri == dummytri) {
+      /* Turn the corner. */
+      triedgecopy(dissolveedge, nextedge);
+    }
+  }
+  triangledealloc(finaledge.tri);
+
+  free(infpoint1);                  /* Deallocate the bounding box vertices. */
+  free(infpoint2);
+  free(infpoint3);
+
+  return hullsize;
+}
+
+#endif /* not REDUCED */
+
+/*****************************************************************************/
+/*                                                                           */
+/*  incrementaldelaunay()   Form a Delaunay triangulation by incrementally   */
+/*                          adding vertices.                                 */
+/*                                                                           */
+/*****************************************************************************/
+
+#ifndef REDUCED
+
+long incrementaldelaunay()
+{
+  struct triedge starttri;
+  point pointloop;
+  int i;
+
+  /* Create a triangular bounding box. */
+  boundingbox();
+  if (verbose) {
+    printf("  Incrementally inserting points.\n");
+  }
+  traversalinit(&points);
+  pointloop = pointtraverse();
+  i = 1;
+  while (pointloop != (point) NULL) {
+    /* Find a boundary triangle to search from. */
+    starttri.tri = (triangle *) NULL;
+    if (insertsite(pointloop, &starttri, (struct edge *) NULL, 0, 0) ==
+        DUPLICATEPOINT) {
+      if (!quiet) {
+        printf(
+"Warning:  A duplicate point at (%.12g, %.12g) appeared and was ignored.\n",
+               pointloop[0], pointloop[1]);
+      }
+/*  Commented out - would eliminate point from output .node file.
+      setpointmark(pointloop, DEADPOINT);
+*/
+    }
+    pointloop = pointtraverse();
+    i++;
+  }
+  /* Remove the bounding box. */
+  return removebox();
+}
+
+#endif /* not REDUCED */
+
+/**                                                                         **/
+/**                                                                         **/
+/********* Incremental Delaunay triangulation ends here              *********/
+
+/********* Sweepline Delaunay triangulation begins here              *********/
+/**                                                                         **/
+/**                                                                         **/
+
+#ifndef REDUCED
+
+void eventheapinsert(heap, heapsize, newevent)
+struct event **heap;
+int heapsize;
+struct event *newevent;
+{
+  REAL eventx, eventy;
+  int eventnum;
+  int parent;
+  int notdone;
+
+  eventx = newevent->xkey;
+  eventy = newevent->ykey;
+  eventnum = heapsize;
+  notdone = eventnum > 0;
+  while (notdone) {
+    parent = (eventnum - 1) >> 1;
+    if ((heap[parent]->ykey < eventy) ||
+        ((heap[parent]->ykey == eventy)
+         && (heap[parent]->xkey <= eventx))) {
+      notdone = 0;
+    } else {
+      heap[eventnum] = heap[parent];
+      heap[eventnum]->heapposition = eventnum;
+
+      eventnum = parent;
+      notdone = eventnum > 0;
+    }
+  }
+  heap[eventnum] = newevent;
+  newevent->heapposition = eventnum;
+}
+
+#endif /* not REDUCED */
+
+#ifndef REDUCED
+
+void eventheapify(heap, heapsize, eventnum)
+struct event **heap;
+int heapsize;
+int eventnum;
+{
+  struct event *thisevent;
+  REAL eventx, eventy;
+  int leftchild, rightchild;
+  int smallest;
+  int notdone;
+
+  thisevent = heap[eventnum];
+  eventx = thisevent->xkey;
+  eventy = thisevent->ykey;
+  leftchild = 2 * eventnum + 1;
+  notdone = leftchild < heapsize;
+  while (notdone) {
+    if ((heap[leftchild]->ykey < eventy) ||
+        ((heap[leftchild]->ykey == eventy)
+         && (heap[leftchild]->xkey < eventx))) {
+      smallest = leftchild;
+    } else {
+      smallest = eventnum;
+    }
+    rightchild = leftchild + 1;
+    if (rightchild < heapsize) {
+      if ((heap[rightchild]->ykey < heap[smallest]->ykey) ||
+          ((heap[rightchild]->ykey == heap[smallest]->ykey)
+           && (heap[rightchild]->xkey < heap[smallest]->xkey))) {
+        smallest = rightchild;
+      }
+    }
+    if (smallest == eventnum) {
+      notdone = 0;
+    } else {
+      heap[eventnum] = heap[smallest];
+      heap[eventnum]->heapposition = eventnum;
+      heap[smallest] = thisevent;
+      thisevent->heapposition = smallest;
+
+      eventnum = smallest;
+      leftchild = 2 * eventnum + 1;
+      notdone = leftchild < heapsize;
+    }
+  }
+}
+
+#endif /* not REDUCED */
+
+#ifndef REDUCED
+
+void eventheapdelete(heap, heapsize, eventnum)
+struct event **heap;
+int heapsize;
+int eventnum;
+{
+  struct event *moveevent;
+  REAL eventx, eventy;
+  int parent;
+  int notdone;
+
+  moveevent = heap[heapsize - 1];
+  if (eventnum > 0) {
+    eventx = moveevent->xkey;
+    eventy = moveevent->ykey;
+    do {
+      parent = (eventnum - 1) >> 1;
+      if ((heap[parent]->ykey < eventy) ||
+          ((heap[parent]->ykey == eventy)
+           && (heap[parent]->xkey <= eventx))) {
+        notdone = 0;
+      } else {
+        heap[eventnum] = heap[parent];
+        heap[eventnum]->heapposition = eventnum;
+
+        eventnum = parent;
+        notdone = eventnum > 0;
+      }
+    } while (notdone);
+  }
+  heap[eventnum] = moveevent;
+  moveevent->heapposition = eventnum;
+  eventheapify(heap, heapsize - 1, eventnum);
+}
+
+#endif /* not REDUCED */
+
+#ifndef REDUCED
+
+void createeventheap(eventheap, events, freeevents)
+struct event ***eventheap;
+struct event **events;
+struct event **freeevents;
+{
+  point thispoint;
+  int maxevents;
+  int i;
+
+  maxevents = (3 * inpoints) / 2;
+  *eventheap = (struct event **) malloc(maxevents * sizeof(struct event *));
+  if (*eventheap == (struct event **) NULL) {
+    printf("Error:  Out of memory.\n");
+    exit(1);
+  }
+  *events = (struct event *) malloc(maxevents * sizeof(struct event));
+  if (*events == (struct event *) NULL) {
+    printf("Error:  Out of memory.\n");
+    exit(1);
+  }
+  traversalinit(&points);
+  for (i = 0; i < inpoints; i++) {
+    thispoint = pointtraverse();
+    (*events)[i].eventptr = (VOID *) thispoint;
+    (*events)[i].xkey = thispoint[0];
+    (*events)[i].ykey = thispoint[1];
+    eventheapinsert(*eventheap, i, *events + i);
+  }
+  *freeevents = (struct event *) NULL;
+  for (i = maxevents - 1; i >= inpoints; i--) {
+    (*events)[i].eventptr = (VOID *) *freeevents;
+    *freeevents = *events + i;
+  }
+}
+
+#endif /* not REDUCED */
+
+#ifndef REDUCED
+
+int rightofhyperbola(fronttri, newsite)
+struct triedge *fronttri;
+point newsite;
+{
+  point leftpoint, rightpoint;
+  REAL dxa, dya, dxb, dyb;
+
+  hyperbolacount++;
+
+  dest(*fronttri, leftpoint);
+  apex(*fronttri, rightpoint);
+  if ((leftpoint[1] < rightpoint[1])
+      || ((leftpoint[1] == rightpoint[1]) && (leftpoint[0] < rightpoint[0]))) {
+    if (newsite[0] >= rightpoint[0]) {
+      return 1;
+    }
+  } else {
+    if (newsite[0] <= leftpoint[0]) {
+      return 0;
+    }
+  }
+  dxa = leftpoint[0] - newsite[0];
+  dya = leftpoint[1] - newsite[1];
+  dxb = rightpoint[0] - newsite[0];
+  dyb = rightpoint[1] - newsite[1];
+  return dya * (dxb * dxb + dyb * dyb) > dyb * (dxa * dxa + dya * dya);
+}
+
+#endif /* not REDUCED */
+
+#ifndef REDUCED
+
+REAL circletop(pa, pb, pc, ccwabc)
+point pa;
+point pb;
+point pc;
+REAL ccwabc;
+{
+  REAL xac, yac, xbc, ybc, xab, yab;
+  REAL aclen2, bclen2, ablen2;
+
+  circletopcount++;
+
+  xac = pa[0] - pc[0];
+  yac = pa[1] - pc[1];
+  xbc = pb[0] - pc[0];
+  ybc = pb[1] - pc[1];
+  xab = pa[0] - pb[0];
+  yab = pa[1] - pb[1];
+  aclen2 = xac * xac + yac * yac;
+  bclen2 = xbc * xbc + ybc * ybc;
+  ablen2 = xab * xab + yab * yab;
+  return pc[1] + (xac * bclen2 - xbc * aclen2 + sqrt(aclen2 * bclen2 * ablen2))
+               / (2.0 * ccwabc);
+}
+
+#endif /* not REDUCED */
+
+#ifndef REDUCED
+
+void check4deadevent(checktri, freeevents, eventheap, heapsize)
+struct triedge *checktri;
+struct event **freeevents;
+struct event **eventheap;
+int *heapsize;
+{
+  struct event *deadevent;
+  point eventpoint;
+  int eventnum;
+
+  org(*checktri, eventpoint);
+  if (eventpoint != (point) NULL) {
+    deadevent = (struct event *) eventpoint;
+    eventnum = deadevent->heapposition;
+    deadevent->eventptr = (VOID *) *freeevents;
+    *freeevents = deadevent;
+    eventheapdelete(eventheap, *heapsize, eventnum);
+    (*heapsize)--;
+    setorg(*checktri, NULL);
+  }
+}
+
+#endif /* not REDUCED */
+
+#ifndef REDUCED
+
+struct splaynode *splay(splaytree, searchpoint, searchtri)
+struct splaynode *splaytree;
+point searchpoint;
+struct triedge *searchtri;
+{
+  struct splaynode *child, *grandchild;
+  struct splaynode *lefttree, *righttree;
+  struct splaynode *leftright;
+  point checkpoint;
+  int rightofroot, rightofchild;
+
+  if (splaytree == (struct splaynode *) NULL) {
+    return (struct splaynode *) NULL;
+  }
+  dest(splaytree->keyedge, checkpoint);
+  if (checkpoint == splaytree->keydest) {
+    rightofroot = rightofhyperbola(&splaytree->keyedge, searchpoint);
+    if (rightofroot) {
+      triedgecopy(splaytree->keyedge, *searchtri);
+      child = splaytree->rchild;
+    } else {
+      child = splaytree->lchild;
+    }
+    if (child == (struct splaynode *) NULL) {
+      return splaytree;
+    }
+    dest(child->keyedge, checkpoint);
+    if (checkpoint != child->keydest) {
+      child = splay(child, searchpoint, searchtri);
+      if (child == (struct splaynode *) NULL) {
+        if (rightofroot) {
+          splaytree->rchild = (struct splaynode *) NULL;
+        } else {
+          splaytree->lchild = (struct splaynode *) NULL;
+        }
+        return splaytree;
+      }
+    }
+    rightofchild = rightofhyperbola(&child->keyedge, searchpoint);
+    if (rightofchild) {
+      triedgecopy(child->keyedge, *searchtri);
+      grandchild = splay(child->rchild, searchpoint, searchtri);
+      child->rchild = grandchild;
+    } else {
+      grandchild = splay(child->lchild, searchpoint, searchtri);
+      child->lchild = grandchild;
+    }
+    if (grandchild == (struct splaynode *) NULL) {
+      if (rightofroot) {
+        splaytree->rchild = child->lchild;
+        child->lchild = splaytree;
+      } else {
+        splaytree->lchild = child->rchild;
+        child->rchild = splaytree;
+      }
+      return child;
+    }
+    if (rightofchild) {
+      if (rightofroot) {
+        splaytree->rchild = child->lchild;
+        child->lchild = splaytree;
+      } else {
+        splaytree->lchild = grandchild->rchild;
+        grandchild->rchild = splaytree;
+      }
+      child->rchild = grandchild->lchild;
+      grandchild->lchild = child;
+    } else {
+      if (rightofroot) {
+        splaytree->rchild = grandchild->lchild;
+        grandchild->lchild = splaytree;
+      } else {
+        splaytree->lchild = child->rchild;
+        child->rchild = splaytree;
+      }
+      child->lchild = grandchild->rchild;
+      grandchild->rchild = child;
+    }
+    return grandchild;
+  } else {
+    lefttree = splay(splaytree->lchild, searchpoint, searchtri);
+    righttree = splay(splaytree->rchild, searchpoint, searchtri);
+
+    pooldealloc(&splaynodes, (VOID *) splaytree);
+    if (lefttree == (struct splaynode *) NULL) {
+      return righttree;
+    } else if (righttree == (struct splaynode *) NULL) {
+      return lefttree;
+    } else if (lefttree->rchild == (struct splaynode *) NULL) {
+      lefttree->rchild = righttree->lchild;
+      righttree->lchild = lefttree;
+      return righttree;
+    } else if (righttree->lchild == (struct splaynode *) NULL) {
+      righttree->lchild = lefttree->rchild;
+      lefttree->rchild = righttree;
+      return lefttree;
+    } else {
+/*      printf("Holy Toledo!!!\n"); */
+      leftright = lefttree->rchild;
+      while (leftright->rchild != (struct splaynode *) NULL) {
+        leftright = leftright->rchild;
+      }
+      leftright->rchild = righttree;
+      return lefttree;
+    }
+  }
+}
+
+#endif /* not REDUCED */
+
+#ifndef REDUCED
+
+struct splaynode *splayinsert(splayroot, newkey, searchpoint)
+struct splaynode *splayroot;
+struct triedge *newkey;
+point searchpoint;
+{
+  struct splaynode *newsplaynode;
+
+  newsplaynode = (struct splaynode *) poolalloc(&splaynodes);
+  triedgecopy(*newkey, newsplaynode->keyedge);
+  dest(*newkey, newsplaynode->keydest);
+  if (splayroot == (struct splaynode *) NULL) {
+    newsplaynode->lchild = (struct splaynode *) NULL;
+    newsplaynode->rchild = (struct splaynode *) NULL;
+  } else if (rightofhyperbola(&splayroot->keyedge, searchpoint)) {
+    newsplaynode->lchild = splayroot;
+    newsplaynode->rchild = splayroot->rchild;
+    splayroot->rchild = (struct splaynode *) NULL;
+  } else {
+    newsplaynode->lchild = splayroot->lchild;
+    newsplaynode->rchild = splayroot;
+    splayroot->lchild = (struct splaynode *) NULL;
+  }
+  return newsplaynode;
+}
+
+#endif /* not REDUCED */
+
+#ifndef REDUCED
+
+struct splaynode *circletopinsert(splayroot, newkey, pa, pb, pc, topy)
+struct splaynode *splayroot;
+struct triedge *newkey;
+point pa;
+point pb;
+point pc;
+REAL topy;
+{
+  REAL ccwabc;
+  REAL xac, yac, xbc, ybc;
+  REAL aclen2, bclen2;
+  REAL searchpoint[2];
+  struct triedge dummytri;
+
+  ccwabc = counterclockwise(pa, pb, pc);
+  xac = pa[0] - pc[0];
+  yac = pa[1] - pc[1];
+  xbc = pb[0] - pc[0];
+  ybc = pb[1] - pc[1];
+  aclen2 = xac * xac + yac * yac;
+  bclen2 = xbc * xbc + ybc * ybc;
+  searchpoint[0] = pc[0] - (yac * bclen2 - ybc * aclen2) / (2.0 * ccwabc);
+  searchpoint[1] = topy;
+  return splayinsert(splay(splayroot, (point) searchpoint, &dummytri), newkey,
+                     (point) searchpoint);
+}
+
+#endif /* not REDUCED */
+
+#ifndef REDUCED
+
+struct splaynode *frontlocate(splayroot, bottommost, searchpoint, searchtri,
+                              farright)
+struct splaynode *splayroot;
+struct triedge *bottommost;
+point searchpoint;
+struct triedge *searchtri;
+int *farright;
+{
+  int farrightflag;
+  triangle ptr;                       /* Temporary variable used by onext(). */
+
+  triedgecopy(*bottommost, *searchtri);
+  splayroot = splay(splayroot, searchpoint, searchtri);
+
+  farrightflag = 0;
+  while (!farrightflag && rightofhyperbola(searchtri, searchpoint)) {
+    onextself(*searchtri);
+    farrightflag = triedgeequal(*searchtri, *bottommost);
+  }
+  *farright = farrightflag;
+  return splayroot;
+}
+
+#endif /* not REDUCED */
+
+#ifndef REDUCED
+
+long sweeplinedelaunay()
+{
+  struct event **eventheap;
+  struct event *events;
+  struct event *freeevents;
+  struct event *nextevent;
+  struct event *newevent;
+  struct splaynode *splayroot;
+  struct triedge bottommost;
+  struct triedge searchtri;
+  struct triedge fliptri;
+  struct triedge lefttri, righttri, farlefttri, farrighttri;
+  struct triedge inserttri;
+  point firstpoint, secondpoint;
+  point nextpoint, lastpoint;
+  point connectpoint;
+  point leftpoint, midpoint, rightpoint;
+  REAL lefttest, righttest;
+  int heapsize;
+  int check4events, farrightflag;
+  triangle ptr;   /* Temporary variable used by sym(), onext(), and oprev(). */
+
+  poolinit(&splaynodes, sizeof(struct splaynode), SPLAYNODEPERBLOCK, POINTER,
+           0);
+  splayroot = (struct splaynode *) NULL;
+
+  if (verbose) {
+    printf("  Placing points in event heap.\n");
+  }
+  createeventheap(&eventheap, &events, &freeevents);
+  heapsize = inpoints;
+
+  if (verbose) {
+    printf("  Forming triangulation.\n");
+  }
+  maketriangle(&lefttri);
+  maketriangle(&righttri);
+  bond(lefttri, righttri);
+  lnextself(lefttri);
+  lprevself(righttri);
+  bond(lefttri, righttri);
+  lnextself(lefttri);
+  lprevself(righttri);
+  bond(lefttri, righttri);
+  firstpoint = (point) eventheap[0]->eventptr;
+  eventheap[0]->eventptr = (VOID *) freeevents;
+  freeevents = eventheap[0];
+  eventheapdelete(eventheap, heapsize, 0);
+  heapsize--;
+  do {
+    if (heapsize == 0) {
+      printf("Error:  Input points are all identical.\n");
+      exit(1);
+    }
+    secondpoint = (point) eventheap[0]->eventptr;
+    eventheap[0]->eventptr = (VOID *) freeevents;
+    freeevents = eventheap[0];
+    eventheapdelete(eventheap, heapsize, 0);
+    heapsize--;
+    if ((firstpoint[0] == secondpoint[0])
+        && (firstpoint[1] == secondpoint[1])) {
+      printf(
+"Warning:  A duplicate point at (%.12g, %.12g) appeared and was ignored.\n",
+             secondpoint[0], secondpoint[1]);
+/*  Commented out - would eliminate point from output .node file.
+      setpointmark(secondpoint, DEADPOINT);
+*/
+    }
+  } while ((firstpoint[0] == secondpoint[0])
+           && (firstpoint[1] == secondpoint[1]));
+  setorg(lefttri, firstpoint);
+  setdest(lefttri, secondpoint);
+  setorg(righttri, secondpoint);
+  setdest(righttri, firstpoint);
+  lprev(lefttri, bottommost);
+  lastpoint = secondpoint;
+  while (heapsize > 0) {
+    nextevent = eventheap[0];
+    eventheapdelete(eventheap, heapsize, 0);
+    heapsize--;
+    check4events = 1;
+    if (nextevent->xkey < xmin) {
+      decode(nextevent->eventptr, fliptri);
+      oprev(fliptri, farlefttri);
+      check4deadevent(&farlefttri, &freeevents, eventheap, &heapsize);
+      onext(fliptri, farrighttri);
+      check4deadevent(&farrighttri, &freeevents, eventheap, &heapsize);
+
+      if (triedgeequal(farlefttri, bottommost)) {
+        lprev(fliptri, bottommost);
+      }
+      flip(&fliptri);
+      setapex(fliptri, NULL);
+      lprev(fliptri, lefttri);
+      lnext(fliptri, righttri);
+      sym(lefttri, farlefttri);
+
+      if (randomnation(SAMPLERATE) == 0) {
+        symself(fliptri);
+        dest(fliptri, leftpoint);
+        apex(fliptri, midpoint);
+        org(fliptri, rightpoint);
+        splayroot = circletopinsert(splayroot, &lefttri, leftpoint, midpoint,
+                                    rightpoint, nextevent->ykey);
+      }
+    } else {
+      nextpoint = (point) nextevent->eventptr;
+      if ((nextpoint[0] == lastpoint[0]) && (nextpoint[1] == lastpoint[1])) {
+        printf(
+"Warning:  A duplicate point at (%.12g, %.12g) appeared and was ignored.\n",
+               nextpoint[0], nextpoint[1]);
+/*  Commented out - would eliminate point from output .node file.
+        setpointmark(nextpoint, DEADPOINT);
+*/
+        check4events = 0;
+      } else {
+        lastpoint = nextpoint;
+
+        splayroot = frontlocate(splayroot, &bottommost, nextpoint, &searchtri,
+                                &farrightflag);
+/*
+        triedgecopy(bottommost, searchtri);
+        farrightflag = 0;
+        while (!farrightflag && rightofhyperbola(&searchtri, nextpoint)) {
+          onextself(searchtri);
+          farrightflag = triedgeequal(searchtri, bottommost);
+        }
+*/
+
+        check4deadevent(&searchtri, &freeevents, eventheap, &heapsize);
+
+        triedgecopy(searchtri, farrighttri);
+        sym(searchtri, farlefttri);
+        maketriangle(&lefttri);
+        maketriangle(&righttri);
+        dest(farrighttri, connectpoint);
+        setorg(lefttri, connectpoint);
+        setdest(lefttri, nextpoint);
+        setorg(righttri, nextpoint);
+        setdest(righttri, connectpoint);
+        bond(lefttri, righttri);
+        lnextself(lefttri);
+        lprevself(righttri);
+        bond(lefttri, righttri);
+        lnextself(lefttri);
+        lprevself(righttri);
+        bond(lefttri, farlefttri);
+        bond(righttri, farrighttri);
+        if (!farrightflag && triedgeequal(farrighttri, bottommost)) {
+          triedgecopy(lefttri, bottommost);
+        }
+
+        if (randomnation(SAMPLERATE) == 0) {
+          splayroot = splayinsert(splayroot, &lefttri, nextpoint);
+        } else if (randomnation(SAMPLERATE) == 0) {
+          lnext(righttri, inserttri);
+          splayroot = splayinsert(splayroot, &inserttri, nextpoint);
+        }
+      }
+    }
+    nextevent->eventptr = (VOID *) freeevents;
+    freeevents = nextevent;
+
+    if (check4events) {
+      apex(farlefttri, leftpoint);
+      dest(lefttri, midpoint);
+      apex(lefttri, rightpoint);
+      lefttest = counterclockwise(leftpoint, midpoint, rightpoint);
+      if (lefttest > 0.0) {
+        newevent = freeevents;
+        freeevents = (struct event *) freeevents->eventptr;
+        newevent->xkey = xminextreme;
+        newevent->ykey = circletop(leftpoint, midpoint, rightpoint,
+                                   lefttest);
+        newevent->eventptr = (VOID *) encode(lefttri);
+        eventheapinsert(eventheap, heapsize, newevent);
+        heapsize++;
+        setorg(lefttri, newevent);
+      }
+      apex(righttri, leftpoint);
+      org(righttri, midpoint);
+      apex(farrighttri, rightpoint);
+      righttest = counterclockwise(leftpoint, midpoint, rightpoint);
+      if (righttest > 0.0) {
+        newevent = freeevents;
+        freeevents = (struct event *) freeevents->eventptr;
+        newevent->xkey = xminextreme;
+        newevent->ykey = circletop(leftpoint, midpoint, rightpoint,
+                                   righttest);
+        newevent->eventptr = (VOID *) encode(farrighttri);
+        eventheapinsert(eventheap, heapsize, newevent);
+        heapsize++;
+        setorg(farrighttri, newevent);
+      }
+    }
+  }
+
+  pooldeinit(&splaynodes);
+  lprevself(bottommost);
+  return removeghosts(&bottommost);
+}
+
+#endif /* not REDUCED */
+
+/**                                                                         **/
+/**                                                                         **/
+/********* Sweepline Delaunay triangulation ends here                *********/
+
+/********* General mesh construction routines begin here             *********/
+/**                                                                         **/
+/**                                                                         **/
+
+/*****************************************************************************/
+/*                                                                           */
+/*  delaunay()   Form a Delaunay triangulation.                              */
+/*                                                                           */
+/*****************************************************************************/
+
+long delaunay()
+{
+  eextras = 0;
+  initializetrisegpools();
+
+#ifdef REDUCED
+  if (!quiet) {
+    printf(
+      "Constructing Delaunay triangulation by divide-and-conquer method.\n");
+  }
+  return divconqdelaunay();
+#else /* not REDUCED */
+  if (!quiet) {
+    printf("Constructing Delaunay triangulation ");
+    if (incremental) {
+      printf("by incremental method.\n");
+    } else if (sweepline) {
+      printf("by sweepline method.\n");
+    } else {
+      printf("by divide-and-conquer method.\n");
+    }
+  }
+  if (incremental) {
+    return incrementaldelaunay();
+  } else if (sweepline) {
+    return sweeplinedelaunay();
+  } else {
+    return divconqdelaunay();
+  }
+#endif /* not REDUCED */
+}
+
+/*****************************************************************************/
+/*                                                                           */
+/*  reconstruct()   Reconstruct a triangulation from its .ele (and possibly  */
+/*                  .poly) file.  Used when the -r switch is used.           */
+/*                                                                           */
+/*  Reads an .ele file and reconstructs the original mesh.  If the -p switch */
+/*  is used, this procedure will also read a .poly file and reconstruct the  */
+/*  shell edges of the original mesh.  If the -a switch is used, this        */
+/*  procedure will also read an .area file and set a maximum area constraint */
+/*  on each triangle.                                                        */
+/*                                                                           */
+/*  Points that are not corners of triangles, such as nodes on edges of      */
+/*  subparametric elements, are discarded.                                   */
+/*                                                                           */
+/*  This routine finds the adjacencies between triangles (and shell edges)   */
+/*  by forming one stack of triangles for each vertex.  Each triangle is on  */
+/*  three different stacks simultaneously.  Each triangle's shell edge       */
+/*  pointers are used to link the items in each stack.  This memory-saving   */
+/*  feature makes the code harder to read.  The most important thing to keep */
+/*  in mind is that each triangle is removed from a stack precisely when     */
+/*  the corresponding pointer is adjusted to refer to a shell edge rather    */
+/*  than the next triangle of the stack.                                     */
+/*                                                                           */
+/*****************************************************************************/
+
+#ifndef CDT_ONLY
+
+#ifdef TRILIBRARY
+
+int reconstruct(trianglelist, triangleattriblist, trianglearealist, elements,
+                corners, attribs, segmentlist, segmentmarkerlist,
+                numberofsegments)
+int *trianglelist;
+REAL *triangleattriblist;
+REAL *trianglearealist;
+int elements;
+int corners;
+int attribs;
+int *segmentlist;
+int *segmentmarkerlist;
+int numberofsegments;
+
+#else /* not TRILIBRARY */
+
+long reconstruct(elefilename, areafilename, polyfilename, polyfile)
+char *elefilename;
+char *areafilename;
+char *polyfilename;
+FILE *polyfile;
+
+#endif /* not TRILIBRARY */
+
+{
+#ifdef TRILIBRARY
+  int pointindex;
+  int attribindex;
+#else /* not TRILIBRARY */
+  FILE *elefile;
+  FILE *areafile;
+  char inputline[INPUTLINESIZE];
+  char *stringptr;
+  int areaelements;
+#endif /* not TRILIBRARY */
+  struct triedge triangleloop;
+  struct triedge triangleleft;
+  struct triedge checktri;
+  struct triedge checkleft;
+  struct triedge checkneighbor;
+  struct edge shelleloop;
+  triangle *vertexarray;
+  triangle *prevlink;
+  triangle nexttri;
+  point tdest, tapex;
+  point checkdest, checkapex;
+  point shorg;
+  point killpoint;
+  REAL area;
+  int corner[3];
+  int end[2];
+  int killpointindex;
+  int incorners;
+  int segmentmarkers;
+  int boundmarker;
+  int aroundpoint;
+  long hullsize;
+  int notfound;
+  int elementnumber, segmentnumber;
+  int i, j;
+  triangle ptr;                         /* Temporary variable used by sym(). */
+
+#ifdef TRILIBRARY
+  inelements = elements;
+  incorners = corners;
+  if (incorners < 3) {
+    printf("Error:  Triangles must have at least 3 points.\n");
+    exit(1);
+  }
+  eextras = attribs;
+#else /* not TRILIBRARY */
+  /* Read the triangles from an .ele file. */
+  if (!quiet) {
+    printf("Opening %s.\n", elefilename);
+  }
+  elefile = fopen(elefilename, "r");
+  if (elefile == (FILE *) NULL) {
+    printf("  Error:  Cannot access file %s.\n", elefilename);
+    exit(1);
+  }
+  /* Read number of triangles, number of points per triangle, and */
+  /*   number of triangle attributes from .ele file.              */
+  stringptr = readline(inputline, elefile, elefilename);
+  inelements = (int) strtol (stringptr, &stringptr, 0);
+  stringptr = findfield(stringptr);
+  if (*stringptr == '\0') {
+    incorners = 3;
+  } else {
+    incorners = (int) strtol (stringptr, &stringptr, 0);
+    if (incorners < 3) {
+      printf("Error:  Triangles in %s must have at least 3 points.\n",
+             elefilename);
+      exit(1);
+    }
+  }
+  stringptr = findfield(stringptr);
+  if (*stringptr == '\0') {
+    eextras = 0;
+  } else {
+    eextras = (int) strtol (stringptr, &stringptr, 0);
+  }
+#endif /* not TRILIBRARY */
+
+  initializetrisegpools();
+
+  /* Create the triangles. */
+  for (elementnumber = 1; elementnumber <= inelements; elementnumber++) {
+    maketriangle(&triangleloop);
+    /* Mark the triangle as living. */
+    triangleloop.tri[3] = (triangle) triangleloop.tri;
+  }
+
+  if (poly) {
+#ifdef TRILIBRARY
+    insegments = numberofsegments;
+    segmentmarkers = segmentmarkerlist != (int *) NULL;
+#else /* not TRILIBRARY */
+    /* Read number of segments and number of segment */
+    /*   boundary markers from .poly file.           */
+    stringptr = readline(inputline, polyfile, inpolyfilename);
+    insegments = (int) strtol (stringptr, &stringptr, 0);
+    stringptr = findfield(stringptr);
+    if (*stringptr == '\0') {
+      segmentmarkers = 0;
+    } else {
+      segmentmarkers = (int) strtol (stringptr, &stringptr, 0);
+    }
+#endif /* not TRILIBRARY */
+
+    /* Create the shell edges. */
+    for (segmentnumber = 1; segmentnumber <= insegments; segmentnumber++) {
+      makeshelle(&shelleloop);
+      /* Mark the shell edge as living. */
+      shelleloop.sh[2] = (shelle) shelleloop.sh;
+    }
+  }
+
+#ifdef TRILIBRARY
+  pointindex = 0;
+  attribindex = 0;
+#else /* not TRILIBRARY */
+  if (vararea) {
+    /* Open an .area file, check for consistency with the .ele file. */
+    if (!quiet) {
+      printf("Opening %s.\n", areafilename);
+    }
+    areafile = fopen(areafilename, "r");
+    if (areafile == (FILE *) NULL) {
+      printf("  Error:  Cannot access file %s.\n", areafilename);
+      exit(1);
+    }
+    stringptr = readline(inputline, areafile, areafilename);
+    areaelements = (int) strtol (stringptr, &stringptr, 0);
+    if (areaelements != inelements) {
+      printf("Error:  %s and %s disagree on number of triangles.\n",
+             elefilename, areafilename);
+      exit(1);
+    }
+  }
+#endif /* not TRILIBRARY */
+
+  if (!quiet) {
+    printf("Reconstructing mesh.\n");
+  }
+  /* Allocate a temporary array that maps each point to some adjacent  */
+  /*   triangle.  I took care to allocate all the permanent memory for */
+  /*   triangles and shell edges first.                                */
+  vertexarray = (triangle *) malloc(points.items * sizeof(triangle));
+  if (vertexarray == (triangle *) NULL) {
+    printf("Error:  Out of memory.\n");
+    exit(1);
+  }
+  /* Each point is initially unrepresented. */
+  for (i = 0; i < points.items; i++) {
+    vertexarray[i] = (triangle) dummytri;
+  }
+
+  if (verbose) {
+    printf("  Assembling triangles.\n");
+  }
+  /* Read the triangles from the .ele file, and link */
+  /*   together those that share an edge.            */
+  traversalinit(&triangles);
+  triangleloop.tri = triangletraverse();
+  elementnumber = firstnumber;
+  while (triangleloop.tri != (triangle *) NULL) {
+#ifdef TRILIBRARY
+    /* Copy the triangle's three corners. */
+    for (j = 0; j < 3; j++) {
+      corner[j] = trianglelist[pointindex++];
+      if ((corner[j] < firstnumber) || (corner[j] >= firstnumber + inpoints)) {
+        printf("Error:  Triangle %d has an invalid vertex index.\n",
+               elementnumber);
+        exit(1);
+      }
+    }
+#else /* not TRILIBRARY */
+    /* Read triangle number and the triangle's three corners. */
+    stringptr = readline(inputline, elefile, elefilename);
+    for (j = 0; j < 3; j++) {
+      stringptr = findfield(stringptr);
+      if (*stringptr == '\0') {
+        printf("Error:  Triangle %d is missing point %d in %s.\n",
+               elementnumber, j + 1, elefilename);
+        exit(1);
+      } else {
+        corner[j] = (int) strtol (stringptr, &stringptr, 0);
+        if ((corner[j] < firstnumber) ||
+            (corner[j] >= firstnumber + inpoints)) {
+          printf("Error:  Triangle %d has an invalid vertex index.\n",
+                 elementnumber);
+          exit(1);
+        }
+      }
+    }
+#endif /* not TRILIBRARY */
+
+    /* Find out about (and throw away) extra nodes. */
+    for (j = 3; j < incorners; j++) {
+#ifdef TRILIBRARY
+      killpointindex = trianglelist[pointindex++];
+#else /* not TRILIBRARY */
+      stringptr = findfield(stringptr);
+      if (*stringptr != '\0') {
+        killpointindex = (int) strtol (stringptr, &stringptr, 0);
+#endif /* not TRILIBRARY */
+        if ((killpointindex >= firstnumber) &&
+            (killpointindex < firstnumber + inpoints)) {
+          /* Delete the non-corner point if it's not already deleted. */
+          killpoint = getpoint(killpointindex);
+          if (pointmark(killpoint) != DEADPOINT) {
+            pointdealloc(killpoint);
+          }
+        }
+#ifndef TRILIBRARY
+      }
+#endif /* not TRILIBRARY */
+    }
+
+    /* Read the triangle's attributes. */
+    for (j = 0; j < eextras; j++) {
+#ifdef TRILIBRARY
+      setelemattribute(triangleloop, j, triangleattriblist[attribindex++]);
+#else /* not TRILIBRARY */
+      stringptr = findfield(stringptr);
+      if (*stringptr == '\0') {
+        setelemattribute(triangleloop, j, 0);
+      } else {
+        setelemattribute(triangleloop, j,
+                         (REAL) strtod (stringptr, &stringptr));
+      }
+#endif /* not TRILIBRARY */
+    }
+
+    if (vararea) {
+#ifdef TRILIBRARY
+      area = trianglearealist[elementnumber - firstnumber];
+#else /* not TRILIBRARY */
+      /* Read an area constraint from the .area file. */
+      stringptr = readline(inputline, areafile, areafilename);
+      stringptr = findfield(stringptr);
+      if (*stringptr == '\0') {
+        area = -1.0;                      /* No constraint on this triangle. */
+      } else {
+        area = (REAL) strtod(stringptr, &stringptr);
+      }
+#endif /* not TRILIBRARY */
+      setareabound(triangleloop, area);
+    }
+
+    /* Set the triangle's vertices. */
+    triangleloop.orient = 0;
+    setorg(triangleloop, getpoint(corner[0]));
+    setdest(triangleloop, getpoint(corner[1]));
+    setapex(triangleloop, getpoint(corner[2]));
+    /* Try linking the triangle to others that share these vertices. */
+    for (triangleloop.orient = 0; triangleloop.orient < 3;
+         triangleloop.orient++) {
+      /* Take the number for the origin of triangleloop. */
+      aroundpoint = corner[triangleloop.orient];
+      /* Look for other triangles having this vertex. */
+      nexttri = vertexarray[aroundpoint - firstnumber];
+      /* Link the current triangle to the next one in the stack. */
+      triangleloop.tri[6 + triangleloop.orient] = nexttri;
+      /* Push the current triangle onto the stack. */
+      vertexarray[aroundpoint - firstnumber] = encode(triangleloop);
+      decode(nexttri, checktri);
+      if (checktri.tri != dummytri) {
+        dest(triangleloop, tdest);
+        apex(triangleloop, tapex);
+        /* Look for other triangles that share an edge. */
+        do {
+          dest(checktri, checkdest);
+          apex(checktri, checkapex);
+          if (tapex == checkdest) {
+            /* The two triangles share an edge; bond them together. */
+            lprev(triangleloop, triangleleft);
+            bond(triangleleft, checktri);
+          }
+          if (tdest == checkapex) {
+            /* The two triangles share an edge; bond them together. */
+            lprev(checktri, checkleft);
+            bond(triangleloop, checkleft);
+          }
+          /* Find the next triangle in the stack. */
+          nexttri = checktri.tri[6 + checktri.orient];
+          decode(nexttri, checktri);
+        } while (checktri.tri != dummytri);
+      }
+    }
+    triangleloop.tri = triangletraverse();
+    elementnumber++;
+  }
+
+#ifdef TRILIBRARY
+  pointindex = 0;
+#else /* not TRILIBRARY */
+  fclose(elefile);
+  if (vararea) {
+    fclose(areafile);
+  }
+#endif /* not TRILIBRARY */
+
+  hullsize = 0;                      /* Prepare to count the boundary edges. */
+  if (poly) {
+    if (verbose) {
+      printf("  Marking segments in triangulation.\n");
+    }
+    /* Read the segments from the .poly file, and link them */
+    /*   to their neighboring triangles.                    */
+    boundmarker = 0;
+    traversalinit(&shelles);
+    shelleloop.sh = shelletraverse();
+    segmentnumber = firstnumber;
+    while (shelleloop.sh != (shelle *) NULL) {
+#ifdef TRILIBRARY
+      end[0] = segmentlist[pointindex++];
+      end[1] = segmentlist[pointindex++];
+      if (segmentmarkers) {
+        boundmarker = segmentmarkerlist[segmentnumber - firstnumber];
+      }
+#else /* not TRILIBRARY */
+      /* Read the endpoints of each segment, and possibly a boundary marker. */
+      stringptr = readline(inputline, polyfile, inpolyfilename);
+      /* Skip the first (segment number) field. */
+      stringptr = findfield(stringptr);
+      if (*stringptr == '\0') {
+        printf("Error:  Segment %d has no endpoints in %s.\n", segmentnumber,
+               polyfilename);
+        exit(1);
+      } else {
+        end[0] = (int) strtol (stringptr, &stringptr, 0);
+      }
+      stringptr = findfield(stringptr);
+      if (*stringptr == '\0') {
+        printf("Error:  Segment %d is missing its second endpoint in %s.\n",
+               segmentnumber, polyfilename);
+        exit(1);
+      } else {
+        end[1] = (int) strtol (stringptr, &stringptr, 0);
+      }
+      if (segmentmarkers) {
+        stringptr = findfield(stringptr);
+        if (*stringptr == '\0') {
+          boundmarker = 0;
+        } else {
+          boundmarker = (int) strtol (stringptr, &stringptr, 0);
+        }
+      }
+#endif /* not TRILIBRARY */
+      for (j = 0; j < 2; j++) {
+        if ((end[j] < firstnumber) || (end[j] >= firstnumber + inpoints)) {
+          printf("Error:  Segment %d has an invalid vertex index.\n", 
+                 segmentnumber);
+          exit(1);
+        }
+      }
+
+      /* set the shell edge's vertices. */
+      shelleloop.shorient = 0;
+      setsorg(shelleloop, getpoint(end[0]));
+      setsdest(shelleloop, getpoint(end[1]));
+      setmark(shelleloop, boundmarker);
+      /* Try linking the shell edge to triangles that share these vertices. */
+      for (shelleloop.shorient = 0; shelleloop.shorient < 2;
+           shelleloop.shorient++) {
+        /* Take the number for the destination of shelleloop. */
+        aroundpoint = end[1 - shelleloop.shorient];
+        /* Look for triangles having this vertex. */
+        prevlink = &vertexarray[aroundpoint - firstnumber];
+        nexttri = vertexarray[aroundpoint - firstnumber];
+        decode(nexttri, checktri);
+        sorg(shelleloop, shorg);
+        notfound = 1;
+        /* Look for triangles having this edge.  Note that I'm only       */
+        /*   comparing each triangle's destination with the shell edge;   */
+        /*   each triangle's apex is handled through a different vertex.  */
+        /*   Because each triangle appears on three vertices' lists, each */
+        /*   occurrence of a triangle on a list can (and does) represent  */
+        /*   an edge.  In this way, most edges are represented twice, and */
+        /*   every triangle-segment bond is represented once.             */
+        while (notfound && (checktri.tri != dummytri)) {
+          dest(checktri, checkdest);
+          if (shorg == checkdest) {
+            /* We have a match.  Remove this triangle from the list. */
+            *prevlink = checktri.tri[6 + checktri.orient];
+            /* Bond the shell edge to the triangle. */
+            tsbond(checktri, shelleloop);
+            /* Check if this is a boundary edge. */
+            sym(checktri, checkneighbor);
+            if (checkneighbor.tri == dummytri) {
+              /* The next line doesn't insert a shell edge (because there's */
+              /*   already one there), but it sets the boundary markers of  */
+              /*   the existing shell edge and its vertices.                */
+              insertshelle(&checktri, 1);
+              hullsize++;
+            }
+            notfound = 0;
+          }
+          /* Find the next triangle in the stack. */
+          prevlink = &checktri.tri[6 + checktri.orient];
+          nexttri = checktri.tri[6 + checktri.orient];
+          decode(nexttri, checktri);
+        }
+      }
+      shelleloop.sh = shelletraverse();
+      segmentnumber++;
+    }
+  }
+
+  /* Mark the remaining edges as not being attached to any shell edge. */
+  /* Also, count the (yet uncounted) boundary edges.                   */
+  for (i = 0; i < points.items; i++) {
+    /* Search the stack of triangles adjacent to a point. */
+    nexttri = vertexarray[i];
+    decode(nexttri, checktri);
+    while (checktri.tri != dummytri) {
+      /* Find the next triangle in the stack before this */
+      /*   information gets overwritten.                 */
+      nexttri = checktri.tri[6 + checktri.orient];
+      /* No adjacent shell edge.  (This overwrites the stack info.) */
+      tsdissolve(checktri);
+      sym(checktri, checkneighbor);
+      if (checkneighbor.tri == dummytri) {
+        insertshelle(&checktri, 1);
+        hullsize++;
+      }
+      decode(nexttri, checktri);
+    }
+  }
+
+  free(vertexarray);
+  return hullsize;
+}
+
+#endif /* not CDT_ONLY */
+
+/**                                                                         **/
+/**                                                                         **/
+/********* General mesh construction routines end here               *********/
+
+/********* Segment (shell edge) insertion begins here                *********/
+/**                                                                         **/
+/**                                                                         **/
+
+/*****************************************************************************/
+/*                                                                           */
+/*  finddirection()   Find the first triangle on the path from one point     */
+/*                    to another.                                            */
+/*                                                                           */
+/*  Finds the triangle that intersects a line segment drawn from the         */
+/*  origin of `searchtri' to the point `endpoint', and returns the result    */
+/*  in `searchtri'.  The origin of `searchtri' does not change, even though  */
+/*  the triangle returned may differ from the one passed in.  This routine   */
+/*  is used to find the direction to move in to get from one point to        */
+/*  another.                                                                 */
+/*                                                                           */
+/*  The return value notes whether the destination or apex of the found      */
+/*  triangle is collinear with the two points in question.                   */
+/*                                                                           */
+/*****************************************************************************/
+
+enum finddirectionresult finddirection(searchtri, endpoint)
+struct triedge *searchtri;
+point endpoint;
+{
+  struct triedge checktri;
+  point startpoint;
+  point leftpoint, rightpoint;
+  REAL leftccw, rightccw;
+  int leftflag, rightflag;
+  triangle ptr;           /* Temporary variable used by onext() and oprev(). */
+
+  org(*searchtri, startpoint);
+  dest(*searchtri, rightpoint);
+  apex(*searchtri, leftpoint);
+  /* Is `endpoint' to the left? */
+  leftccw = counterclockwise(endpoint, startpoint, leftpoint);
+  leftflag = leftccw > 0.0;
+  /* Is `endpoint' to the right? */
+  rightccw = counterclockwise(startpoint, endpoint, rightpoint);
+  rightflag = rightccw > 0.0;
+  if (leftflag && rightflag) {
+    /* `searchtri' faces directly away from `endpoint'.  We could go */
+    /*   left or right.  Ask whether it's a triangle or a boundary   */
+    /*   on the left.                                                */
+    onext(*searchtri, checktri);
+    if (checktri.tri == dummytri) {
+      leftflag = 0;
+    } else {
+      rightflag = 0;
+    }
+  }
+  while (leftflag) {
+    /* Turn left until satisfied. */
+    onextself(*searchtri);
+    if (searchtri->tri == dummytri) {
+      printf("Internal error in finddirection():  Unable to find a\n");
+      printf("  triangle leading from (%.12g, %.12g) to", startpoint[0],
+             startpoint[1]);
+      printf("  (%.12g, %.12g).\n", endpoint[0], endpoint[1]);
+      internalerror();
+    }
+    apex(*searchtri, leftpoint);
+    rightccw = leftccw;
+    leftccw = counterclockwise(endpoint, startpoint, leftpoint);
+    leftflag = leftccw > 0.0;
+  }
+  while (rightflag) {
+    /* Turn right until satisfied. */
+    oprevself(*searchtri);
+    if (searchtri->tri == dummytri) {
+      printf("Internal error in finddirection():  Unable to find a\n");
+      printf("  triangle leading from (%.12g, %.12g) to", startpoint[0],
+             startpoint[1]);
+      printf("  (%.12g, %.12g).\n", endpoint[0], endpoint[1]);
+      internalerror();
+    }
+    dest(*searchtri, rightpoint);
+    leftccw = rightccw;
+    rightccw = counterclockwise(startpoint, endpoint, rightpoint);
+    rightflag = rightccw > 0.0;
+  }
+  if (leftccw == 0.0) {
+    return LEFTCOLLINEAR;
+  } else if (rightccw == 0.0) {
+    return RIGHTCOLLINEAR;
+  } else {
+    return WITHIN;
+  }
+}
+
+/*****************************************************************************/
+/*                                                                           */
+/*  segmentintersection()   Find the intersection of an existing segment     */
+/*                          and a segment that is being inserted.  Insert    */
+/*                          a point at the intersection, splitting an        */
+/*                          existing shell edge.                             */
+/*                                                                           */
+/*  The segment being inserted connects the apex of splittri to endpoint2.   */
+/*  splitshelle is the shell edge being split, and MUST be opposite          */
+/*  splittri.  Hence, the edge being split connects the origin and           */
+/*  destination of splittri.                                                 */
+/*                                                                           */
+/*  On completion, splittri is a handle having the newly inserted            */
+/*  intersection point as its origin, and endpoint1 as its destination.      */
+/*                                                                           */
+/*****************************************************************************/
+
+void segmentintersection(splittri, splitshelle, endpoint2)
+struct triedge *splittri;
+struct edge *splitshelle;
+point endpoint2;
+{
+  point endpoint1;
+  point torg, tdest;
+  point leftpoint, rightpoint;
+  point newpoint;
+  enum insertsiteresult success;
+  enum finddirectionresult collinear;
+  REAL ex, ey;
+  REAL tx, ty;
+  REAL etx, ety;
+  REAL split, denom;
+  int i;
+  triangle ptr;                       /* Temporary variable used by onext(). */
+
+  /* Find the other three segment endpoints. */
+  apex(*splittri, endpoint1);
+  org(*splittri, torg);
+  dest(*splittri, tdest);
+  /* Segment intersection formulae; see the Antonio reference. */
+  tx = tdest[0] - torg[0];
+  ty = tdest[1] - torg[1];
+  ex = endpoint2[0] - endpoint1[0];
+  ey = endpoint2[1] - endpoint1[1];
+  etx = torg[0] - endpoint2[0];
+  ety = torg[1] - endpoint2[1];
+  denom = ty * ex - tx * ey;
+  if (denom == 0.0) {
+    printf("Internal error in segmentintersection():");
+    printf("  Attempt to find intersection of parallel segments.\n");
+    internalerror();
+  }
+  split = (ey * etx - ex * ety) / denom;
+  /* Create the new point. */
+  newpoint = (point) poolalloc(&points);
+  /* Interpolate its coordinate and attributes. */
+  for (i = 0; i < 2 + nextras; i++) {
+    newpoint[i] = torg[i] + split * (tdest[i] - torg[i]);
+  }
+  setpointmark(newpoint, mark(*splitshelle));
+  if (verbose > 1) {
+    printf(
+    "  Splitting edge (%.12g, %.12g) (%.12g, %.12g) at (%.12g, %.12g).\n",
+           torg[0], torg[1], tdest[0], tdest[1], newpoint[0], newpoint[1]);
+  }
+  /* Insert the intersection point.  This should always succeed. */
+  success = insertsite(newpoint, splittri, splitshelle, 0, 0);
+  if (success != SUCCESSFULPOINT) {
+    printf("Internal error in segmentintersection():\n");
+    printf("  Failure to split a segment.\n");
+    internalerror();
+  }
+  if (steinerleft > 0) {
+    steinerleft--;
+  }
+  /* Inserting the point may have caused edge flips.  We wish to rediscover */
+  /*   the edge connecting endpoint1 to the new intersection point.         */
+  collinear = finddirection(splittri, endpoint1);
+  dest(*splittri, rightpoint);
+  apex(*splittri, leftpoint);
+  if ((leftpoint[0] == endpoint1[0]) && (leftpoint[1] == endpoint1[1])) {
+    onextself(*splittri);
+  } else if ((rightpoint[0] != endpoint1[0]) ||
+             (rightpoint[1] != endpoint1[1])) {
+    printf("Internal error in segmentintersection():\n");
+    printf("  Topological inconsistency after splitting a segment.\n");
+    internalerror();
+  }
+  /* `splittri' should have destination endpoint1. */
+}
+
+/*****************************************************************************/
+/*                                                                           */
+/*  scoutsegment()   Scout the first triangle on the path from one endpoint  */
+/*                   to another, and check for completion (reaching the      */
+/*                   second endpoint), a collinear point, and the            */
+/*                   intersection of two segments.                           */
+/*                                                                           */
+/*  Returns one if the entire segment is successfully inserted, and zero if  */
+/*  the job must be finished by conformingedge() or constrainededge().       */
+/*                                                                           */
+/*  If the first triangle on the path has the second endpoint as its         */
+/*  destination or apex, a shell edge is inserted and the job is done.       */
+/*                                                                           */
+/*  If the first triangle on the path has a destination or apex that lies on */
+/*  the segment, a shell edge is inserted connecting the first endpoint to   */
+/*  the collinear point, and the search is continued from the collinear      */
+/*  point.                                                                   */
+/*                                                                           */
+/*  If the first triangle on the path has a shell edge opposite its origin,  */
+/*  then there is a segment that intersects the segment being inserted.      */
+/*  Their intersection point is inserted, splitting the shell edge.          */
+/*                                                                           */
+/*  Otherwise, return zero.                                                  */
+/*                                                                           */
+/*****************************************************************************/
+
+int scoutsegment(searchtri, endpoint2, newmark)
+struct triedge *searchtri;
+point endpoint2;
+int newmark;
+{
+  struct triedge crosstri;
+  struct edge crossedge;
+  point leftpoint, rightpoint;
+  point endpoint1;
+  enum finddirectionresult collinear;
+  shelle sptr;                      /* Temporary variable used by tspivot(). */
+
+  collinear = finddirection(searchtri, endpoint2);
+  dest(*searchtri, rightpoint);
+  apex(*searchtri, leftpoint);
+  if (((leftpoint[0] == endpoint2[0]) && (leftpoint[1] == endpoint2[1])) ||
+      ((rightpoint[0] == endpoint2[0]) && (rightpoint[1] == endpoint2[1]))) {
+    /* The segment is already an edge in the mesh. */
+    if ((leftpoint[0] == endpoint2[0]) && (leftpoint[1] == endpoint2[1])) {
+      lprevself(*searchtri);
+    }
+    /* Insert a shell edge, if there isn't already one there. */
+    insertshelle(searchtri, newmark);
+    return 1;
+  } else if (collinear == LEFTCOLLINEAR) {
+    /* We've collided with a point between the segment's endpoints. */
+    /* Make the collinear point be the triangle's origin. */
+    lprevself(*searchtri);
+    insertshelle(searchtri, newmark);
+    /* Insert the remainder of the segment. */
+    return scoutsegment(searchtri, endpoint2, newmark);
+  } else if (collinear == RIGHTCOLLINEAR) {
+    /* We've collided with a point between the segment's endpoints. */
+    insertshelle(searchtri, newmark);
+    /* Make the collinear point be the triangle's origin. */
+    lnextself(*searchtri);
+    /* Insert the remainder of the segment. */
+    return scoutsegment(searchtri, endpoint2, newmark);
+  } else {
+    lnext(*searchtri, crosstri);
+    tspivot(crosstri, crossedge);
+    /* Check for a crossing segment. */
+    if (crossedge.sh == dummysh) {
+      return 0;
+    } else {
+      org(*searchtri, endpoint1);
+      /* Insert a point at the intersection. */
+      segmentintersection(&crosstri, &crossedge, endpoint2);
+      triedgecopy(crosstri, *searchtri);
+      insertshelle(searchtri, newmark);
+      /* Insert the remainder of the segment. */
+      return scoutsegment(searchtri, endpoint2, newmark);
+    }
+  }
+}
+
+/*****************************************************************************/
+/*                                                                           */
+/*  conformingedge()   Force a segment into a conforming Delaunay            */
+/*                     triangulation by inserting a point at its midpoint,   */
+/*                     and recursively forcing in the two half-segments if   */
+/*                     necessary.                                            */
+/*                                                                           */
+/*  Generates a sequence of edges connecting `endpoint1' to `endpoint2'.     */
+/*  `newmark' is the boundary marker of the segment, assigned to each new    */
+/*  splitting point and shell edge.                                          */
+/*                                                                           */
+/*  Note that conformingedge() does not always maintain the conforming       */
+/*  Delaunay property.  Once inserted, segments are locked into place;       */
+/*  points inserted later (to force other segments in) may render these      */
+/*  fixed segments non-Delaunay.  The conforming Delaunay property will be   */
+/*  restored by enforcequality() by splitting encroached segments.           */
+/*                                                                           */
+/*****************************************************************************/
+
+#ifndef REDUCED
+#ifndef CDT_ONLY
+
+void conformingedge(endpoint1, endpoint2, newmark)
+point endpoint1;
+point endpoint2;
+int newmark;
+{
+  struct triedge searchtri1, searchtri2;
+  struct edge brokenshelle;
+  point newpoint;
+  point midpoint1, midpoint2;
+  enum insertsiteresult success;
+  int result1, result2;
+  int i;
+  shelle sptr;                      /* Temporary variable used by tspivot(). */
+
+  if (verbose > 2) {
+    printf("Forcing segment into triangulation by recursive splitting:\n");
+    printf("  (%.12g, %.12g) (%.12g, %.12g)\n", endpoint1[0], endpoint1[1],
+           endpoint2[0], endpoint2[1]);
+  }
+  /* Create a new point to insert in the middle of the segment. */
+  newpoint = (point) poolalloc(&points);
+  /* Interpolate coordinates and attributes. */
+  for (i = 0; i < 2 + nextras; i++) {
+    newpoint[i] = 0.5 * (endpoint1[i] + endpoint2[i]);
+  }
+  setpointmark(newpoint, newmark);
+  /* Find a boundary triangle to search from. */
+  searchtri1.tri = (triangle *) NULL;
+  /* Attempt to insert the new point. */
+  success = insertsite(newpoint, &searchtri1, (struct edge *) NULL, 0, 0);
+  if (success == DUPLICATEPOINT) {
+    if (verbose > 2) {
+      printf("  Segment intersects existing point (%.12g, %.12g).\n",
+             newpoint[0], newpoint[1]);
+    }
+    /* Use the point that's already there. */
+    pointdealloc(newpoint);
+    org(searchtri1, newpoint);
+  } else {
+    if (success == VIOLATINGPOINT) {
+      if (verbose > 2) {
+        printf("  Two segments intersect at (%.12g, %.12g).\n",
+               newpoint[0], newpoint[1]);
+      }
+      /* By fluke, we've landed right on another segment.  Split it. */
+      tspivot(searchtri1, brokenshelle);
+      success = insertsite(newpoint, &searchtri1, &brokenshelle, 0, 0);
+      if (success != SUCCESSFULPOINT) {
+        printf("Internal error in conformingedge():\n");
+        printf("  Failure to split a segment.\n");
+        internalerror();
+      }
+    }
+    /* The point has been inserted successfully. */
+    if (steinerleft > 0) {
+      steinerleft--;
+    }
+  }
+  triedgecopy(searchtri1, searchtri2);
+  result1 = scoutsegment(&searchtri1, endpoint1, newmark);
+  result2 = scoutsegment(&searchtri2, endpoint2, newmark);
+  if (!result1) {
+    /* The origin of searchtri1 may have changed if a collision with an */
+    /*   intervening vertex on the segment occurred.                    */
+    org(searchtri1, midpoint1);
+    conformingedge(midpoint1, endpoint1, newmark);
+  }
+  if (!result2) {
+    /* The origin of searchtri2 may have changed if a collision with an */
+    /*   intervening vertex on the segment occurred.                    */
+    org(searchtri2, midpoint2);
+    conformingedge(midpoint2, endpoint2, newmark);
+  }
+}
+
+#endif /* not CDT_ONLY */
+#endif /* not REDUCED */
+
+/*****************************************************************************/
+/*                                                                           */
+/*  delaunayfixup()   Enforce the Delaunay condition at an edge, fanning out */
+/*                    recursively from an existing point.  Pay special       */
+/*                    attention to stacking inverted triangles.              */
+/*                                                                           */
+/*  This is a support routine for inserting segments into a constrained      */
+/*  Delaunay triangulation.                                                  */
+/*                                                                           */
+/*  The origin of fixuptri is treated as if it has just been inserted, and   */
+/*  the local Delaunay condition needs to be enforced.  It is only enforced  */
+/*  in one sector, however, that being the angular range defined by          */
+/*  fixuptri.                                                                */
+/*                                                                           */
+/*  This routine also needs to make decisions regarding the "stacking" of    */
+/*  triangles.  (Read the description of constrainededge() below before      */
+/*  reading on here, so you understand the algorithm.)  If the position of   */
+/*  the new point (the origin of fixuptri) indicates that the vertex before  */
+/*  it on the polygon is a reflex vertex, then "stack" the triangle by       */
+/*  doing nothing.  (fixuptri is an inverted triangle, which is how stacked  */
+/*  triangles are identified.)                                               */
+/*                                                                           */
+/*  Otherwise, check whether the vertex before that was a reflex vertex.     */
+/*  If so, perform an edge flip, thereby eliminating an inverted triangle    */
+/*  (popping it off the stack).  The edge flip may result in the creation    */
+/*  of a new inverted triangle, depending on whether or not the new vertex   */
+/*  is visible to the vertex three edges behind on the polygon.              */
+/*                                                                           */
+/*  If neither of the two vertices behind the new vertex are reflex          */
+/*  vertices, fixuptri and fartri, the triangle opposite it, are not         */
+/*  inverted; hence, ensure that the edge between them is locally Delaunay.  */
+/*                                                                           */
+/*  `leftside' indicates whether or not fixuptri is to the left of the       */
+/*  segment being inserted.  (Imagine that the segment is pointing up from   */
+/*  endpoint1 to endpoint2.)                                                 */
+/*                                                                           */
+/*****************************************************************************/
+
+void delaunayfixup(fixuptri, leftside)
+struct triedge *fixuptri;
+int leftside;
+{
+  struct triedge neartri;
+  struct triedge fartri;
+  struct edge faredge;
+  point nearpoint, leftpoint, rightpoint, farpoint;
+  triangle ptr;                         /* Temporary variable used by sym(). */
+  shelle sptr;                      /* Temporary variable used by tspivot(). */
+
+  lnext(*fixuptri, neartri);
+  sym(neartri, fartri);
+  /* Check if the edge opposite the origin of fixuptri can be flipped. */
+  if (fartri.tri == dummytri) {
+    return;
+  }
+  tspivot(neartri, faredge);
+  if (faredge.sh != dummysh) {
+    return;
+  }
+  /* Find all the relevant vertices. */
+  apex(neartri, nearpoint);
+  org(neartri, leftpoint);
+  dest(neartri, rightpoint);
+  apex(fartri, farpoint);
+  /* Check whether the previous polygon vertex is a reflex vertex. */
+  if (leftside) {
+    if (counterclockwise(nearpoint, leftpoint, farpoint) <= 0.0) {
+      /* leftpoint is a reflex vertex too.  Nothing can */
+      /*   be done until a convex section is found.     */
+      return;
+    }
+  } else {
+    if (counterclockwise(farpoint, rightpoint, nearpoint) <= 0.0) {
+      /* rightpoint is a reflex vertex too.  Nothing can */
+      /*   be done until a convex section is found.      */
+      return;
+    }
+  }
+  if (counterclockwise(rightpoint, leftpoint, farpoint) > 0.0) {
+    /* fartri is not an inverted triangle, and farpoint is not a reflex */
+    /*   vertex.  As there are no reflex vertices, fixuptri isn't an    */
+    /*   inverted triangle, either.  Hence, test the edge between the   */
+    /*   triangles to ensure it is locally Delaunay.                    */
+    if (incircle(leftpoint, farpoint, rightpoint, nearpoint) <= 0.0) {
+      return;
+    }
+    /* Not locally Delaunay; go on to an edge flip. */
+  }        /* else fartri is inverted; remove it from the stack by flipping. */
+  flip(&neartri);
+  lprevself(*fixuptri);    /* Restore the origin of fixuptri after the flip. */
+  /* Recursively process the two triangles that result from the flip. */
+  delaunayfixup(fixuptri, leftside);
+  delaunayfixup(&fartri, leftside);
+}
+
+/*****************************************************************************/
+/*                                                                           */
+/*  constrainededge()   Force a segment into a constrained Delaunay          */
+/*                      triangulation by deleting the triangles it           */
+/*                      intersects, and triangulating the polygons that      */
+/*                      form on each side of it.                             */
+/*                                                                           */
+/*  Generates a single edge connecting `endpoint1' to `endpoint2'.  The      */
+/*  triangle `starttri' has `endpoint1' as its origin.  `newmark' is the     */
+/*  boundary marker of the segment.                                          */
+/*                                                                           */
+/*  To insert a segment, every triangle whose interior intersects the        */
+/*  segment is deleted.  The union of these deleted triangles is a polygon   */
+/*  (which is not necessarily monotone, but is close enough), which is       */
+/*  divided into two polygons by the new segment.  This routine's task is    */
+/*  to generate the Delaunay triangulation of these two polygons.            */
+/*                                                                           */
+/*  You might think of this routine's behavior as a two-step process.  The   */
+/*  first step is to walk from endpoint1 to endpoint2, flipping each edge    */
+/*  encountered.  This step creates a fan of edges connected to endpoint1,   */
+/*  including the desired edge to endpoint2.  The second step enforces the   */
+/*  Delaunay condition on each side of the segment in an incremental manner: */
+/*  proceeding along the polygon from endpoint1 to endpoint2 (this is done   */
+/*  independently on each side of the segment), each vertex is "enforced"    */
+/*  as if it had just been inserted, but affecting only the previous         */
+/*  vertices.  The result is the same as if the vertices had been inserted   */
+/*  in the order they appear on the polygon, so the result is Delaunay.      */
+/*                                                                           */
+/*  In truth, constrainededge() interleaves these two steps.  The procedure  */
+/*  walks from endpoint1 to endpoint2, and each time an edge is encountered  */
+/*  and flipped, the newly exposed vertex (at the far end of the flipped     */
+/*  edge) is "enforced" upon the previously flipped edges, usually affecting */
+/*  only one side of the polygon (depending upon which side of the segment   */
+/*  the vertex falls on).                                                    */
+/*                                                                           */
+/*  The algorithm is complicated by the need to handle polygons that are not */
+/*  convex.  Although the polygon is not necessarily monotone, it can be     */
+/*  triangulated in a manner similar to the stack-based algorithms for       */
+/*  monotone polygons.  For each reflex vertex (local concavity) of the      */
+/*  polygon, there will be an inverted triangle formed by one of the edge    */
+/*  flips.  (An inverted triangle is one with negative area - that is, its   */
+/*  vertices are arranged in clockwise order - and is best thought of as a   */
+/*  wrinkle in the fabric of the mesh.)  Each inverted triangle can be       */
+/*  thought of as a reflex vertex pushed on the stack, waiting to be fixed   */
+/*  later.                                                                   */
+/*                                                                           */
+/*  A reflex vertex is popped from the stack when a vertex is inserted that  */
+/*  is visible to the reflex vertex.  (However, if the vertex behind the     */
+/*  reflex vertex is not visible to the reflex vertex, a new inverted        */
+/*  triangle will take its place on the stack.)  These details are handled   */
+/*  by the delaunayfixup() routine above.                                    */
+/*                                                                           */
+/*****************************************************************************/
+
+void constrainededge(starttri, endpoint2, newmark)
+struct triedge *starttri;
+point endpoint2;
+int newmark;
+{
+  struct triedge fixuptri, fixuptri2;
+  struct edge fixupedge;
+  point endpoint1;
+  point farpoint;
+  REAL area;
+  int collision;
+  int done;
+  triangle ptr;             /* Temporary variable used by sym() and oprev(). */
+  shelle sptr;                      /* Temporary variable used by tspivot(). */
+
+  org(*starttri, endpoint1);
+  lnext(*starttri, fixuptri);
+  flip(&fixuptri);
+  /* `collision' indicates whether we have found a point directly */
+  /*   between endpoint1 and endpoint2.                           */
+  collision = 0;
+  done = 0;
+  do {
+    org(fixuptri, farpoint);
+    /* `farpoint' is the extreme point of the polygon we are "digging" */
+    /*   to get from endpoint1 to endpoint2.                           */
+    if ((farpoint[0] == endpoint2[0]) && (farpoint[1] == endpoint2[1])) {
+      oprev(fixuptri, fixuptri2);
+      /* Enforce the Delaunay condition around endpoint2. */
+      delaunayfixup(&fixuptri, 0);
+      delaunayfixup(&fixuptri2, 1);
+      done = 1;
+    } else {
+      /* Check whether farpoint is to the left or right of the segment */
+      /*   being inserted, to decide which edge of fixuptri to dig     */
+      /*   through next.                                               */
+      area = counterclockwise(endpoint1, endpoint2, farpoint);
+      if (area == 0.0) {
+        /* We've collided with a point between endpoint1 and endpoint2. */
+        collision = 1;
+        oprev(fixuptri, fixuptri2);
+        /* Enforce the Delaunay condition around farpoint. */
+        delaunayfixup(&fixuptri, 0);
+        delaunayfixup(&fixuptri2, 1);
+        done = 1;
+      } else {
+        if (area > 0.0) {         /* farpoint is to the left of the segment. */
+          oprev(fixuptri, fixuptri2);
+          /* Enforce the Delaunay condition around farpoint, on the */
+          /*   left side of the segment only.                       */
+          delaunayfixup(&fixuptri2, 1);
+          /* Flip the edge that crosses the segment.  After the edge is */
+          /*   flipped, one of its endpoints is the fan vertex, and the */
+          /*   destination of fixuptri is the fan vertex.               */
+          lprevself(fixuptri);
+        } else {                 /* farpoint is to the right of the segment. */
+          delaunayfixup(&fixuptri, 0);
+          /* Flip the edge that crosses the segment.  After the edge is */
+          /*   flipped, one of its endpoints is the fan vertex, and the */
+          /*   destination of fixuptri is the fan vertex.               */
+          oprevself(fixuptri);
+        }
+        /* Check for two intersecting segments. */
+        tspivot(fixuptri, fixupedge);
+        if (fixupedge.sh == dummysh) {
+          flip(&fixuptri);   /* May create an inverted triangle on the left. */
+        } else {
+          /* We've collided with a segment between endpoint1 and endpoint2. */
+          collision = 1;
+          /* Insert a point at the intersection. */
+          segmentintersection(&fixuptri, &fixupedge, endpoint2);
+          done = 1;
+        }
+      }
+    }
+  } while (!done);
+  /* Insert a shell edge to make the segment permanent. */
+  insertshelle(&fixuptri, newmark);
+  /* If there was a collision with an interceding vertex, install another */
+  /*   segment connecting that vertex with endpoint2.                     */
+  if (collision) {
+    /* Insert the remainder of the segment. */
+    if (!scoutsegment(&fixuptri, endpoint2, newmark)) {
+      constrainededge(&fixuptri, endpoint2, newmark);
+    }
+  }
+}
+
+/*****************************************************************************/
+/*                                                                           */
+/*  insertsegment()   Insert a PSLG segment into a triangulation.            */
+/*                                                                           */
+/*****************************************************************************/
+
+void insertsegment(endpoint1, endpoint2, newmark)
+point endpoint1;
+point endpoint2;
+int newmark;
+{
+  struct triedge searchtri1, searchtri2;
+  triangle encodedtri;
+  point checkpoint;
+  triangle ptr;                         /* Temporary variable used by sym(). */
+
+  if (verbose > 1) {
+    printf("  Connecting (%.12g, %.12g) to (%.12g, %.12g).\n",
+           endpoint1[0], endpoint1[1], endpoint2[0], endpoint2[1]);
+  }
+
+  /* Find a triangle whose origin is the segment's first endpoint. */
+  checkpoint = (point) NULL;
+  encodedtri = point2tri(endpoint1);
+  if (encodedtri != (triangle) NULL) {
+    decode(encodedtri, searchtri1);
+    org(searchtri1, checkpoint);
+  }
+  if (checkpoint != endpoint1) {
+    /* Find a boundary triangle to search from. */
+    searchtri1.tri = dummytri;
+    searchtri1.orient = 0;
+    symself(searchtri1);
+    /* Search for the segment's first endpoint by point location. */
+    if (locate(endpoint1, &searchtri1) != ONVERTEX) {
+      printf(
+        "Internal error in insertsegment():  Unable to locate PSLG point\n");
+      printf("  (%.12g, %.12g) in triangulation.\n",
+             endpoint1[0], endpoint1[1]);
+      internalerror();
+    }
+  }
+  /* Remember this triangle to improve subsequent point location. */
+  triedgecopy(searchtri1, recenttri);
+  /* Scout the beginnings of a path from the first endpoint */
+  /*   toward the second.                                   */
+  if (scoutsegment(&searchtri1, endpoint2, newmark)) {
+    /* The segment was easily inserted. */
+    return;
+  }
+  /* The first endpoint may have changed if a collision with an intervening */
+  /*   vertex on the segment occurred.                                      */
+  org(searchtri1, endpoint1);
+
+  /* Find a triangle whose origin is the segment's second endpoint. */
+  checkpoint = (point) NULL;
+  encodedtri = point2tri(endpoint2);
+  if (encodedtri != (triangle) NULL) {
+    decode(encodedtri, searchtri2);
+    org(searchtri2, checkpoint);
+  }
+  if (checkpoint != endpoint2) {
+    /* Find a boundary triangle to search from. */
+    searchtri2.tri = dummytri;
+    searchtri2.orient = 0;
+    symself(searchtri2);
+    /* Search for the segment's second endpoint by point location. */
+    if (locate(endpoint2, &searchtri2) != ONVERTEX) {
+      printf(
+        "Internal error in insertsegment():  Unable to locate PSLG point\n");
+      printf("  (%.12g, %.12g) in triangulation.\n",
+             endpoint2[0], endpoint2[1]);
+      internalerror();
+    }
+  }
+  /* Remember this triangle to improve subsequent point location. */
+  triedgecopy(searchtri2, recenttri);
+  /* Scout the beginnings of a path from the second endpoint */
+  /*   toward the first.                                     */
+  if (scoutsegment(&searchtri2, endpoint1, newmark)) {
+    /* The segment was easily inserted. */
+    return;
+  }
+  /* The second endpoint may have changed if a collision with an intervening */
+  /*   vertex on the segment occurred.                                       */
+  org(searchtri2, endpoint2);
+
+#ifndef REDUCED
+#ifndef CDT_ONLY
+  if (splitseg) {
+    /* Insert vertices to force the segment into the triangulation. */
+    conformingedge(endpoint1, endpoint2, newmark);
+  } else {
+#endif /* not CDT_ONLY */
+#endif /* not REDUCED */
+    /* Insert the segment directly into the triangulation. */
+    constrainededge(&searchtri1, endpoint2, newmark);
+#ifndef REDUCED
+#ifndef CDT_ONLY
+  }
+#endif /* not CDT_ONLY */
+#endif /* not REDUCED */
+}
+
+/*****************************************************************************/
+/*                                                                           */
+/*  markhull()   Cover the convex hull of a triangulation with shell edges.  */
+/*                                                                           */
+/*****************************************************************************/
+
+void markhull()
+{
+  struct triedge hulltri;
+  struct triedge nexttri;
+  struct triedge starttri;
+  triangle ptr;             /* Temporary variable used by sym() and oprev(). */
+
+  /* Find a triangle handle on the hull. */
+  hulltri.tri = dummytri;
+  hulltri.orient = 0;
+  symself(hulltri);
+  /* Remember where we started so we know when to stop. */
+  triedgecopy(hulltri, starttri);
+  /* Go once counterclockwise around the convex hull. */
+  do {
+    /* Create a shell edge if there isn't already one here. */
+    insertshelle(&hulltri, 1);
+    /* To find the next hull edge, go clockwise around the next vertex. */
+    lnextself(hulltri);
+    oprev(hulltri, nexttri);
+    while (nexttri.tri != dummytri) {
+      triedgecopy(nexttri, hulltri);
+      oprev(hulltri, nexttri);
+    }
+  } while (!triedgeequal(hulltri, starttri));
+}
+
+/*****************************************************************************/
+/*                                                                           */
+/*  formskeleton()   Create the shell edges of a triangulation, including    */
+/*                   PSLG edges and edges on the convex hull.                */
+/*                                                                           */
+/*  The PSLG edges are read from a .poly file.  The return value is the      */
+/*  number of segments in the file.                                          */
+/*                                                                           */
+/*****************************************************************************/
+
+#ifdef TRILIBRARY
+
+int formskeleton(segmentlist, segmentmarkerlist, numberofsegments)
+int *segmentlist;
+int *segmentmarkerlist;
+int numberofsegments;
+
+#else /* not TRILIBRARY */
+
+int formskeleton(polyfile, polyfilename)
+FILE *polyfile;
+char *polyfilename;
+
+#endif /* not TRILIBRARY */
+
+{
+#ifdef TRILIBRARY
+  char polyfilename[6];
+  int index;
+#else /* not TRILIBRARY */
+  char inputline[INPUTLINESIZE];
+  char *stringptr;
+#endif /* not TRILIBRARY */
+  point endpoint1, endpoint2;
+  int segments;
+  int segmentmarkers;
+  int end1, end2;
+  int boundmarker;
+  int i;
+
+  if (poly) {
+    if (!quiet) {
+      printf("Inserting segments into Delaunay triangulation.\n");
+    }
+#ifdef TRILIBRARY
+    strcpy(polyfilename, "input");
+    segments = numberofsegments;
+    segmentmarkers = segmentmarkerlist != (int *) NULL;
+    index = 0;
+#else /* not TRILIBRARY */
+    /* Read the segments from a .poly file. */
+    /* Read number of segments and number of boundary markers. */
+    stringptr = readline(inputline, polyfile, polyfilename);
+    segments = (int) strtol (stringptr, &stringptr, 0);
+    stringptr = findfield(stringptr);
+    if (*stringptr == '\0') {
+      segmentmarkers = 0;
+    } else {
+      segmentmarkers = (int) strtol (stringptr, &stringptr, 0);
+    }
+#endif /* not TRILIBRARY */
+    /* If segments are to be inserted, compute a mapping */
+    /*   from points to triangles.                       */
+    if (segments > 0) {
+      if (verbose) {
+        printf("  Inserting PSLG segments.\n");
+      }
+      makepointmap();
+    }
+
+    boundmarker = 0;
+    /* Read and insert the segments. */
+    for (i = 1; i <= segments; i++) {
+#ifdef TRILIBRARY
+      end1 = segmentlist[index++];
+      end2 = segmentlist[index++];
+      if (segmentmarkers) {
+        boundmarker = segmentmarkerlist[i - 1];
+      }
+#else /* not TRILIBRARY */
+      stringptr = readline(inputline, polyfile, inpolyfilename);
+      stringptr = findfield(stringptr);
+      if (*stringptr == '\0') {
+        printf("Error:  Segment %d has no endpoints in %s.\n", i,
+               polyfilename);
+        exit(1);
+      } else {
+        end1 = (int) strtol (stringptr, &stringptr, 0);
+      }
+      stringptr = findfield(stringptr);
+      if (*stringptr == '\0') {
+        printf("Error:  Segment %d is missing its second endpoint in %s.\n", i,
+               polyfilename);
+        exit(1);
+      } else {
+        end2 = (int) strtol (stringptr, &stringptr, 0);
+      }
+      if (segmentmarkers) {
+        stringptr = findfield(stringptr);
+        if (*stringptr == '\0') {
+          boundmarker = 0;
+        } else {
+          boundmarker = (int) strtol (stringptr, &stringptr, 0);
+        }
+      }
+#endif /* not TRILIBRARY */
+      if ((end1 < firstnumber) || (end1 >= firstnumber + inpoints)) {
+        if (!quiet) {
+          printf("Warning:  Invalid first endpoint of segment %d in %s.\n", i,
+                 polyfilename);
+        }
+      } else if ((end2 < firstnumber) || (end2 >= firstnumber + inpoints)) {
+        if (!quiet) {
+          printf("Warning:  Invalid second endpoint of segment %d in %s.\n", i,
+                 polyfilename);
+        }
+      } else {
+        endpoint1 = getpoint(end1);
+        endpoint2 = getpoint(end2);
+        if ((endpoint1[0] == endpoint2[0]) && (endpoint1[1] == endpoint2[1])) {
+          if (!quiet) {
+            printf("Warning:  Endpoints of segment %d are coincident in %s.\n",
+                   i, polyfilename);
+          }
+        } else {
+          insertsegment(endpoint1, endpoint2, boundmarker);
+        }
+      }
+    }
+  } else {
+    segments = 0;
+  }
+  if (convex || !poly) {
+    /* Enclose the convex hull with shell edges. */
+    if (verbose) {
+      printf("  Enclosing convex hull with segments.\n");
+    }
+    markhull();
+  }
+  return segments;
+}
+
+/**                                                                         **/
+/**                                                                         **/
+/********* Segment (shell edge) insertion ends here                  *********/
+
+/********* Carving out holes and concavities begins here             *********/
+/**                                                                         **/
+/**                                                                         **/
+
+/*****************************************************************************/
+/*                                                                           */
+/*  infecthull()   Virally infect all of the triangles of the convex hull    */
+/*                 that are not protected by shell edges.  Where there are   */
+/*                 shell edges, set boundary markers as appropriate.         */
+/*                                                                           */
+/*****************************************************************************/
+
+void infecthull()
+{
+  struct triedge hulltri;
+  struct triedge nexttri;
+  struct triedge starttri;
+  struct edge hulledge;
+  triangle **deadtri;
+  point horg, hdest;
+  triangle ptr;                         /* Temporary variable used by sym(). */
+  shelle sptr;                      /* Temporary variable used by tspivot(). */
+
+  if (verbose) {
+    printf("  Marking concavities (external triangles) for elimination.\n");
+  }
+  /* Find a triangle handle on the hull. */
+  hulltri.tri = dummytri;
+  hulltri.orient = 0;
+  symself(hulltri);
+  /* Remember where we started so we know when to stop. */
+  triedgecopy(hulltri, starttri);
+  /* Go once counterclockwise around the convex hull. */
+  do {
+    /* Ignore triangles that are already infected. */
+    if (!infected(hulltri)) {
+      /* Is the triangle protected by a shell edge? */
+      tspivot(hulltri, hulledge);
+      if (hulledge.sh == dummysh) {
+        /* The triangle is not protected; infect it. */
+        infect(hulltri);
+        deadtri = (triangle **) poolalloc(&viri);
+        *deadtri = hulltri.tri;
+      } else {
+        /* The triangle is protected; set boundary markers if appropriate. */
+        if (mark(hulledge) == 0) {
+          setmark(hulledge, 1);
+          org(hulltri, horg);
+          dest(hulltri, hdest);
+          if (pointmark(horg) == 0) {
+            setpointmark(horg, 1);
+          }
+          if (pointmark(hdest) == 0) {
+            setpointmark(hdest, 1);
+          }
+        }
+      }
+    }
+    /* To find the next hull edge, go clockwise around the next vertex. */
+    lnextself(hulltri);
+    oprev(hulltri, nexttri);
+    while (nexttri.tri != dummytri) {
+      triedgecopy(nexttri, hulltri);
+      oprev(hulltri, nexttri);
+    }
+  } while (!triedgeequal(hulltri, starttri));
+}
+
+/*****************************************************************************/
+/*                                                                           */
+/*  plague()   Spread the virus from all infected triangles to any neighbors */
+/*             not protected by shell edges.  Delete all infected triangles. */
+/*                                                                           */
+/*  This is the procedure that actually creates holes and concavities.       */
+/*                                                                           */
+/*  This procedure operates in two phases.  The first phase identifies all   */
+/*  the triangles that will die, and marks them as infected.  They are       */
+/*  marked to ensure that each triangle is added to the virus pool only      */
+/*  once, so the procedure will terminate.                                   */
+/*                                                                           */
+/*  The second phase actually eliminates the infected triangles.  It also    */
+/*  eliminates orphaned points.                                              */
+/*                                                                           */
+/*****************************************************************************/
+
+void plague()
+{
+  struct triedge testtri;
+  struct triedge neighbor;
+  triangle **virusloop;
+  triangle **deadtri;
+  struct edge neighborshelle;
+  point testpoint;
+  point norg, ndest;
+  point deadorg, deaddest, deadapex;
+  int killorg;
+  triangle ptr;             /* Temporary variable used by sym() and onext(). */
+  shelle sptr;                      /* Temporary variable used by tspivot(). */
+
+  if (verbose) {
+    printf("  Marking neighbors of marked triangles.\n");
+  }
+  /* Loop through all the infected triangles, spreading the virus to */
+  /*   their neighbors, then to their neighbors' neighbors.          */
+  traversalinit(&viri);
+  virusloop = (triangle **) traverse(&viri);
+  while (virusloop != (triangle **) NULL) {
+    testtri.tri = *virusloop;
+    /* A triangle is marked as infected by messing with one of its shell */
+    /*   edges, setting it to an illegal value.  Hence, we have to       */
+    /*   temporarily uninfect this triangle so that we can examine its   */
+    /*   adjacent shell edges.                                           */
+    uninfect(testtri);
+    if (verbose > 2) {
+      /* Assign the triangle an orientation for convenience in */
+      /*   checking its points.                                */
+      testtri.orient = 0;
+      org(testtri, deadorg);
+      dest(testtri, deaddest);
+      apex(testtri, deadapex);
+      printf("    Checking (%.12g, %.12g) (%.12g, %.12g) (%.12g, %.12g)\n",
+             deadorg[0], deadorg[1], deaddest[0], deaddest[1],
+             deadapex[0], deadapex[1]);
+    }
+    /* Check each of the triangle's three neighbors. */
+    for (testtri.orient = 0; testtri.orient < 3; testtri.orient++) {
+      /* Find the neighbor. */
+      sym(testtri, neighbor);
+      /* Check for a shell between the triangle and its neighbor. */
+      tspivot(testtri, neighborshelle);
+      /* Check if the neighbor is nonexistent or already infected. */
+      if ((neighbor.tri == dummytri) || infected(neighbor)) {
+        if (neighborshelle.sh != dummysh) {
+          /* There is a shell edge separating the triangle from its */
+          /*   neighbor, but both triangles are dying, so the shell */
+          /*   edge dies too.                                       */
+          shelledealloc(neighborshelle.sh);
+          if (neighbor.tri != dummytri) {
+            /* Make sure the shell edge doesn't get deallocated again */
+            /*   later when the infected neighbor is visited.         */
+            uninfect(neighbor);
+            tsdissolve(neighbor);
+            infect(neighbor);
+          }
+        }
+      } else {                   /* The neighbor exists and is not infected. */
+        if (neighborshelle.sh == dummysh) {
+          /* There is no shell edge protecting the neighbor, so */
+          /*   the neighbor becomes infected.                   */
+          if (verbose > 2) {
+            org(neighbor, deadorg);
+            dest(neighbor, deaddest);
+            apex(neighbor, deadapex);
+            printf(
+              "    Marking (%.12g, %.12g) (%.12g, %.12g) (%.12g, %.12g)\n",
+                   deadorg[0], deadorg[1], deaddest[0], deaddest[1],
+                   deadapex[0], deadapex[1]);
+          }
+          infect(neighbor);
+          /* Ensure that the neighbor's neighbors will be infected. */
+          deadtri = (triangle **) poolalloc(&viri);
+          *deadtri = neighbor.tri;
+        } else {               /* The neighbor is protected by a shell edge. */
+          /* Remove this triangle from the shell edge. */
+          stdissolve(neighborshelle);
+          /* The shell edge becomes a boundary.  Set markers accordingly. */
+          if (mark(neighborshelle) == 0) {
+            setmark(neighborshelle, 1);
+          }
+          org(neighbor, norg);
+          dest(neighbor, ndest);
+          if (pointmark(norg) == 0) {
+            setpointmark(norg, 1);
+          }
+          if (pointmark(ndest) == 0) {
+            setpointmark(ndest, 1);
+          }
+        }
+      }
+    }
+    /* Remark the triangle as infected, so it doesn't get added to the */
+    /*   virus pool again.                                             */
+    infect(testtri);
+    virusloop = (triangle **) traverse(&viri);
+  }
+
+  if (verbose) {
+    printf("  Deleting marked triangles.\n");
+  }
+  traversalinit(&viri);
+  virusloop = (triangle **) traverse(&viri);
+  while (virusloop != (triangle **) NULL) {
+    testtri.tri = *virusloop;
+
+    /* Check each of the three corners of the triangle for elimination. */
+    /*   This is done by walking around each point, checking if it is   */
+    /*   still connected to at least one live triangle.                 */
+    for (testtri.orient = 0; testtri.orient < 3; testtri.orient++) {
+      org(testtri, testpoint);
+      /* Check if the point has already been tested. */
+      if (testpoint != (point) NULL) {
+        killorg = 1;
+        /* Mark the corner of the triangle as having been tested. */
+        setorg(testtri, NULL);
+        /* Walk counterclockwise about the point. */
+        onext(testtri, neighbor);
+        /* Stop upon reaching a boundary or the starting triangle. */
+        while ((neighbor.tri != dummytri)
+               && (!triedgeequal(neighbor, testtri))) {
+          if (infected(neighbor)) {
+            /* Mark the corner of this triangle as having been tested. */
+            setorg(neighbor, NULL);
+          } else {
+            /* A live triangle.  The point survives. */
+            killorg = 0;
+          }
+          /* Walk counterclockwise about the point. */
+          onextself(neighbor);
+        }
+        /* If we reached a boundary, we must walk clockwise as well. */
+        if (neighbor.tri == dummytri) {
+          /* Walk clockwise about the point. */
+          oprev(testtri, neighbor);
+          /* Stop upon reaching a boundary. */
+          while (neighbor.tri != dummytri) {
+            if (infected(neighbor)) {
+            /* Mark the corner of this triangle as having been tested. */
+              setorg(neighbor, NULL);
+            } else {
+              /* A live triangle.  The point survives. */
+              killorg = 0;
+            }
+            /* Walk clockwise about the point. */
+            oprevself(neighbor);
+          }
+        }
+        if (killorg) {
+          if (verbose > 1) {
+            printf("    Deleting point (%.12g, %.12g)\n",
+                   testpoint[0], testpoint[1]);
+          }
+          pointdealloc(testpoint);
+        }
+      }
+    }
+
+    /* Record changes in the number of boundary edges, and disconnect */
+    /*   dead triangles from their neighbors.                         */
+    for (testtri.orient = 0; testtri.orient < 3; testtri.orient++) {
+      sym(testtri, neighbor);
+      if (neighbor.tri == dummytri) {
+        /* There is no neighboring triangle on this edge, so this edge    */
+        /*   is a boundary edge.  This triangle is being deleted, so this */
+        /*   boundary edge is deleted.                                    */
+        hullsize--;
+      } else {
+        /* Disconnect the triangle from its neighbor. */
+        dissolve(neighbor);
+        /* There is a neighboring triangle on this edge, so this edge */
+        /*   becomes a boundary edge when this triangle is deleted.   */
+        hullsize++;
+      }
+    }
+    /* Return the dead triangle to the pool of triangles. */
+    triangledealloc(testtri.tri);
+    virusloop = (triangle **) traverse(&viri);
+  }
+  /* Empty the virus pool. */
+  poolrestart(&viri);
+}
+
+/*****************************************************************************/
+/*                                                                           */
+/*  regionplague()   Spread regional attributes and/or area constraints      */
+/*                   (from a .poly file) throughout the mesh.                */
+/*                                                                           */
+/*  This procedure operates in two phases.  The first phase spreads an       */
+/*  attribute and/or an area constraint through a (segment-bounded) region.  */
+/*  The triangles are marked to ensure that each triangle is added to the    */
+/*  virus pool only once, so the procedure will terminate.                   */
+/*                                                                           */
+/*  The second phase uninfects all infected triangles, returning them to     */
+/*  normal.                                                                  */
+/*                                                                           */
+/*****************************************************************************/
+
+void regionplague(attribute, area)
+REAL attribute;
+REAL area;
+{
+  struct triedge testtri;
+  struct triedge neighbor;
+  triangle **virusloop;
+  triangle **regiontri;
+  struct edge neighborshelle;
+  point regionorg, regiondest, regionapex;
+  triangle ptr;             /* Temporary variable used by sym() and onext(). */
+  shelle sptr;                      /* Temporary variable used by tspivot(). */
+
+  if (verbose > 1) {
+    printf("  Marking neighbors of marked triangles.\n");
+  }
+  /* Loop through all the infected triangles, spreading the attribute      */
+  /*   and/or area constraint to their neighbors, then to their neighbors' */
+  /*   neighbors.                                                          */
+  traversalinit(&viri);
+  virusloop = (triangle **) traverse(&viri);
+  while (virusloop != (triangle **) NULL) {
+    testtri.tri = *virusloop;
+    /* A triangle is marked as infected by messing with one of its shell */
+    /*   edges, setting it to an illegal value.  Hence, we have to       */
+    /*   temporarily uninfect this triangle so that we can examine its   */
+    /*   adjacent shell edges.                                           */
+    uninfect(testtri);
+    if (regionattrib) {
+      /* Set an attribute. */
+      setelemattribute(testtri, eextras, attribute);
+    }
+    if (vararea) {
+      /* Set an area constraint. */
+      setareabound(testtri, area);
+    }
+    if (verbose > 2) {
+      /* Assign the triangle an orientation for convenience in */
+      /*   checking its points.                                */
+      testtri.orient = 0;
+      org(testtri, regionorg);
+      dest(testtri, regiondest);
+      apex(testtri, regionapex);
+      printf("    Checking (%.12g, %.12g) (%.12g, %.12g) (%.12g, %.12g)\n",
+             regionorg[0], regionorg[1], regiondest[0], regiondest[1],
+             regionapex[0], regionapex[1]);
+    }
+    /* Check each of the triangle's three neighbors. */
+    for (testtri.orient = 0; testtri.orient < 3; testtri.orient++) {
+      /* Find the neighbor. */
+      sym(testtri, neighbor);
+      /* Check for a shell between the triangle and its neighbor. */
+      tspivot(testtri, neighborshelle);
+      /* Make sure the neighbor exists, is not already infected, and */
+      /*   isn't protected by a shell edge.                          */
+      if ((neighbor.tri != dummytri) && !infected(neighbor)
+          && (neighborshelle.sh == dummysh)) {
+        if (verbose > 2) {
+          org(neighbor, regionorg);
+          dest(neighbor, regiondest);
+          apex(neighbor, regionapex);
+          printf("    Marking (%.12g, %.12g) (%.12g, %.12g) (%.12g, %.12g)\n",
+                 regionorg[0], regionorg[1], regiondest[0], regiondest[1],
+                 regionapex[0], regionapex[1]);
+        }
+        /* Infect the neighbor. */
+        infect(neighbor);
+        /* Ensure that the neighbor's neighbors will be infected. */
+        regiontri = (triangle **) poolalloc(&viri);
+        *regiontri = neighbor.tri;
+      }
+    }
+    /* Remark the triangle as infected, so it doesn't get added to the */
+    /*   virus pool again.                                             */
+    infect(testtri);
+    virusloop = (triangle **) traverse(&viri);
+  }
+
+  /* Uninfect all triangles. */
+  if (verbose > 1) {
+    printf("  Unmarking marked triangles.\n");
+  }
+  traversalinit(&viri);
+  virusloop = (triangle **) traverse(&viri);
+  while (virusloop != (triangle **) NULL) {
+    testtri.tri = *virusloop;
+    uninfect(testtri);
+    virusloop = (triangle **) traverse(&viri);
+  }
+  /* Empty the virus pool. */
+  poolrestart(&viri);
+}
+
+/*****************************************************************************/
+/*                                                                           */
+/*  carveholes()   Find the holes and infect them.  Find the area            */
+/*                 constraints and infect them.  Infect the convex hull.     */
+/*                 Spread the infection and kill triangles.  Spread the      */
+/*                 area constraints.                                         */
+/*                                                                           */
+/*  This routine mainly calls other routines to carry out all these          */
+/*  functions.                                                               */
+/*                                                                           */
+/*****************************************************************************/
+
+void carveholes(holelist, holes, regionlist, regions)
+REAL *holelist;
+int holes;
+REAL *regionlist;
+int regions;
+{
+  struct triedge searchtri;
+  struct triedge triangleloop;
+  struct triedge *regiontris;
+  triangle **holetri;
+  triangle **regiontri;
+  point searchorg, searchdest;
+  enum locateresult intersect;
+  int i;
+  triangle ptr;                         /* Temporary variable used by sym(). */
+
+  if (!(quiet || (noholes && convex))) {
+    printf("Removing unwanted triangles.\n");
+    if (verbose && (holes > 0)) {
+      printf("  Marking holes for elimination.\n");
+    }
+  }
+
+  if (regions > 0) {
+    /* Allocate storage for the triangles in which region points fall. */
+    regiontris = (struct triedge *) malloc(regions * sizeof(struct triedge));
+    if (regiontris == (struct triedge *) NULL) {
+      printf("Error:  Out of memory.\n");
+      exit(1);
+    }
+  }
+
+  if (((holes > 0) && !noholes) || !convex || (regions > 0)) {
+    /* Initialize a pool of viri to be used for holes, concavities, */
+    /*   regional attributes, and/or regional area constraints.     */
+    poolinit(&viri, sizeof(triangle *), VIRUSPERBLOCK, POINTER, 0);
+  }
+
+  if (!convex) {
+    /* Mark as infected any unprotected triangles on the boundary. */
+    /*   This is one way by which concavities are created.         */
+    infecthull();
+  }
+
+  if ((holes > 0) && !noholes) {
+    /* Infect each triangle in which a hole lies. */
+    for (i = 0; i < 2 * holes; i += 2) {
+      /* Ignore holes that aren't within the bounds of the mesh. */
+      if ((holelist[i] >= xmin) && (holelist[i] <= xmax)
+          && (holelist[i + 1] >= ymin) && (holelist[i + 1] <= ymax)) {
+        /* Start searching from some triangle on the outer boundary. */
+        searchtri.tri = dummytri;
+        searchtri.orient = 0;
+        symself(searchtri);
+        /* Ensure that the hole is to the left of this boundary edge; */
+        /*   otherwise, locate() will falsely report that the hole    */
+        /*   falls within the starting triangle.                      */
+        org(searchtri, searchorg);
+        dest(searchtri, searchdest);
+        if (counterclockwise(searchorg, searchdest, &holelist[i]) > 0.0) {
+          /* Find a triangle that contains the hole. */
+          intersect = locate(&holelist[i], &searchtri);
+          if ((intersect != OUTSIDE) && (!infected(searchtri))) {
+            /* Infect the triangle.  This is done by marking the triangle */
+            /*   as infect and including the triangle in the virus pool.  */
+            infect(searchtri);
+            holetri = (triangle **) poolalloc(&viri);
+            *holetri = searchtri.tri;
+          }
+        }
+      }
+    }
+  }
+
+  /* Now, we have to find all the regions BEFORE we carve the holes, because */
+  /*   locate() won't work when the triangulation is no longer convex.       */
+  /*   (Incidentally, this is the reason why regional attributes and area    */
+  /*   constraints can't be used when refining a preexisting mesh, which     */
+  /*   might not be convex; they can only be used with a freshly             */
+  /*   triangulated PSLG.)                                                   */
+  if (regions > 0) {
+    /* Find the starting triangle for each region. */
+    for (i = 0; i < regions; i++) {
+      regiontris[i].tri = dummytri;
+      /* Ignore region points that aren't within the bounds of the mesh. */
+      if ((regionlist[4 * i] >= xmin) && (regionlist[4 * i] <= xmax) &&
+          (regionlist[4 * i + 1] >= ymin) && (regionlist[4 * i + 1] <= ymax)) {
+        /* Start searching from some triangle on the outer boundary. */
+        searchtri.tri = dummytri;
+        searchtri.orient = 0;
+        symself(searchtri);
+        /* Ensure that the region point is to the left of this boundary */
+        /*   edge; otherwise, locate() will falsely report that the     */
+        /*   region point falls within the starting triangle.           */
+        org(searchtri, searchorg);
+        dest(searchtri, searchdest);
+        if (counterclockwise(searchorg, searchdest, &regionlist[4 * i]) >
+            0.0) {
+          /* Find a triangle that contains the region point. */
+          intersect = locate(&regionlist[4 * i], &searchtri);
+          if ((intersect != OUTSIDE) && (!infected(searchtri))) {
+            /* Record the triangle for processing after the */
+            /*   holes have been carved.                    */
+            triedgecopy(searchtri, regiontris[i]);
+          }
+        }
+      }
+    }
+  }
+
+  if (viri.items > 0) {
+    /* Carve the holes and concavities. */
+    plague();
+  }
+  /* The virus pool should be empty now. */
+
+  if (regions > 0) {
+    if (!quiet) {
+      if (regionattrib) {
+        if (vararea) {
+          printf("Spreading regional attributes and area constraints.\n");
+        } else {
+          printf("Spreading regional attributes.\n");
+        }
+      } else { 
+        printf("Spreading regional area constraints.\n");
+      }
+    }
+    if (regionattrib && !refine) {
+      /* Assign every triangle a regional attribute of zero. */
+      traversalinit(&triangles);
+      triangleloop.orient = 0;
+      triangleloop.tri = triangletraverse();
+      while (triangleloop.tri != (triangle *) NULL) {
+        setelemattribute(triangleloop, eextras, 0.0);
+        triangleloop.tri = triangletraverse();
+      }
+    }
+    for (i = 0; i < regions; i++) {
+      if (regiontris[i].tri != dummytri) {
+        /* Make sure the triangle under consideration still exists. */
+        /*   It may have been eaten by the virus.                   */
+        if (regiontris[i].tri[3] != (triangle) NULL) {
+          /* Put one triangle in the virus pool. */
+          infect(regiontris[i]);
+          regiontri = (triangle **) poolalloc(&viri);
+          *regiontri = regiontris[i].tri;
+          /* Apply one region's attribute and/or area constraint. */
+          regionplague(regionlist[4 * i + 2], regionlist[4 * i + 3]);
+          /* The virus pool should be empty now. */
+        }
+      }
+    }
+    if (regionattrib && !refine) {
+      /* Note the fact that each triangle has an additional attribute. */
+      eextras++;
+    }
+  }
+
+  /* Free up memory. */
+  if (((holes > 0) && !noholes) || !convex || (regions > 0)) {
+    pooldeinit(&viri);
+  }
+  if (regions > 0) {
+    free(regiontris);
+  }
+}
+
+/**                                                                         **/
+/**                                                                         **/
+/********* Carving out holes and concavities ends here               *********/
+
+/********* Mesh quality maintenance begins here                      *********/
+/**                                                                         **/
+/**                                                                         **/
+
+/*****************************************************************************/
+/*                                                                           */
+/*  tallyencs()   Traverse the entire list of shell edges, check each edge   */
+/*                to see if it is encroached.  If so, add it to the list.    */
+/*                                                                           */
+/*****************************************************************************/
+
+#ifndef CDT_ONLY
+
+void tallyencs()
+{
+  struct edge edgeloop;
+  int dummy;
+
+  traversalinit(&shelles);
+  edgeloop.shorient = 0;
+  edgeloop.sh = shelletraverse();
+  while (edgeloop.sh != (shelle *) NULL) {
+    /* If the segment is encroached, add it to the list. */
+    dummy = checkedge4encroach(&edgeloop);
+    edgeloop.sh = shelletraverse();
+  }
+}
+
+#endif /* not CDT_ONLY */
+
+/*****************************************************************************/
+/*                                                                           */
+/*  precisionerror()  Print an error message for precision problems.         */
+/*                                                                           */
+/*****************************************************************************/
+
+#ifndef CDT_ONLY
+
+void precisionerror()
+{
+  printf("Try increasing the area criterion and/or reducing the minimum\n");
+  printf("  allowable angle so that tiny triangles are not created.\n");
+#ifdef SINGLE
+  printf("Alternatively, try recompiling me with double precision\n");
+  printf("  arithmetic (by removing \"#define SINGLE\" from the\n");
+  printf("  source file or \"-DSINGLE\" from the makefile).\n");
+#endif /* SINGLE */
+}
+
+#endif /* not CDT_ONLY */
+
+/*****************************************************************************/
+/*                                                                           */
+/*  repairencs()   Find and repair all the encroached segments.              */
+/*                                                                           */
+/*  Encroached segments are repaired by splitting them by inserting a point  */
+/*  at or near their centers.                                                */
+/*                                                                           */
+/*  `flaws' is a flag that specifies whether one should take note of new     */
+/*  encroached segments and bad triangles that result from inserting points  */
+/*  to repair existing encroached segments.                                  */
+/*                                                                           */
+/*  When a segment is split, the two resulting subsegments are always        */
+/*  tested to see if they are encroached upon, regardless of the value       */
+/*  of `flaws'.                                                              */
+/*                                                                           */
+/*****************************************************************************/
+
+#ifndef CDT_ONLY
+
+void repairencs(flaws)
+int flaws;
+{
+  struct triedge enctri;
+  struct triedge testtri;
+  struct edge *encloop;
+  struct edge testsh;
+  point eorg, edest;
+  point newpoint;
+  enum insertsiteresult success;
+  REAL segmentlength, nearestpoweroftwo;
+  REAL split;
+  int acuteorg, acutedest;
+  int dummy;
+  int i;
+  triangle ptr;                     /* Temporary variable used by stpivot(). */
+  shelle sptr;                        /* Temporary variable used by snext(). */
+
+  while ((badsegments.items > 0) && (steinerleft != 0)) {
+    traversalinit(&badsegments);
+    encloop = badsegmenttraverse();
+    while ((encloop != (struct edge *) NULL) && (steinerleft != 0)) {
+      /* To decide where to split a segment, we need to know if the  */
+      /*   segment shares an endpoint with an adjacent segment.      */
+      /*   The concern is that, if we simply split every encroached  */
+      /*   segment in its center, two adjacent segments with a small */
+      /*   angle between them might lead to an infinite loop; each   */
+      /*   point added to split one segment will encroach upon the   */
+      /*   other segment, which must then be split with a point that */
+      /*   will encroach upon the first segment, and so on forever.  */
+      /* To avoid this, imagine a set of concentric circles, whose   */
+      /*   radii are powers of two, about each segment endpoint.     */
+      /*   These concentric circles determine where the segment is   */
+      /*   split.  (If both endpoints are shared with adjacent       */
+      /*   segments, split the segment in the middle, and apply the  */
+      /*   concentric shells for later splittings.)                  */
+
+      /* Is the origin shared with another segment? */
+      stpivot(*encloop, enctri);
+      lnext(enctri, testtri);
+      tspivot(testtri, testsh);
+      acuteorg = testsh.sh != dummysh;
+      /* Is the destination shared with another segment? */
+      lnextself(testtri);
+      tspivot(testtri, testsh);
+      acutedest = testsh.sh != dummysh;
+      /* Now, check the other side of the segment, if there's a triangle */
+      /*   there.                                                        */
+      sym(enctri, testtri);
+      if (testtri.tri != dummytri) {
+        /* Is the destination shared with another segment? */
+        lnextself(testtri);
+        tspivot(testtri, testsh);
+        acutedest = acutedest || (testsh.sh != dummysh);
+        /* Is the origin shared with another segment? */
+        lnextself(testtri);
+        tspivot(testtri, testsh);
+        acuteorg = acuteorg || (testsh.sh != dummysh);
+      }
+
+      sorg(*encloop, eorg);
+      sdest(*encloop, edest);
+      /* Use the concentric circles if exactly one endpoint is shared */
+      /*   with another adjacent segment.                             */
+      if (acuteorg ^ acutedest) {
+        segmentlength = sqrt((edest[0] - eorg[0]) * (edest[0] - eorg[0])
+                             + (edest[1] - eorg[1]) * (edest[1] - eorg[1]));
+        /* Find the power of two nearest the segment's length. */
+        nearestpoweroftwo = 1.0;
+        while (segmentlength > SQUAREROOTTWO * nearestpoweroftwo) {
+          nearestpoweroftwo *= 2.0;
+        }
+        while (segmentlength < (0.5 * SQUAREROOTTWO) * nearestpoweroftwo) {
+          nearestpoweroftwo *= 0.5;
+        }
+        /* Where do we split the segment? */
+        split = 0.5 * nearestpoweroftwo / segmentlength;
+        if (acutedest) {
+          split = 1.0 - split;
+        }
+      } else {
+        /* If we're not worried about adjacent segments, split */
+        /*   this segment in the middle.                       */
+        split = 0.5;
+      }
+
+      /* Create the new point. */
+      newpoint = (point) poolalloc(&points);
+      /* Interpolate its coordinate and attributes. */
+      for (i = 0; i < 2 + nextras; i++) {
+        newpoint[i] = (1.0 - split) * eorg[i] + split * edest[i];
+      }
+      setpointmark(newpoint, mark(*encloop));
+      if (verbose > 1) {
+        printf(
+        "  Splitting edge (%.12g, %.12g) (%.12g, %.12g) at (%.12g, %.12g).\n",
+               eorg[0], eorg[1], edest[0], edest[1], newpoint[0], newpoint[1]);
+      }
+      /* Check whether the new point lies on an endpoint. */
+      if (((newpoint[0] == eorg[0]) && (newpoint[1] == eorg[1]))
+        || ((newpoint[0] == edest[0]) && (newpoint[1] == edest[1]))) {
+        printf("Error:  Ran out of precision at (%.12g, %.12g).\n",
+               newpoint[0], newpoint[1]);
+        printf("I attempted to split a segment to a smaller size than can\n");
+        printf("  be accommodated by the finite precision of floating point\n"
+               );
+        printf("  arithmetic.\n");
+        precisionerror();
+        exit(1);
+      }
+      /* Insert the splitting point.  This should always succeed. */
+      success = insertsite(newpoint, &enctri, encloop, flaws, flaws);
+      if ((success != SUCCESSFULPOINT) && (success != ENCROACHINGPOINT)) {
+        printf("Internal error in repairencs():\n");
+        printf("  Failure to split a segment.\n");
+        internalerror();
+      }
+      if (steinerleft > 0) {
+        steinerleft--;
+      }
+      /* Check the two new subsegments to see if they're encroached. */
+      dummy = checkedge4encroach(encloop);
+      snextself(*encloop);
+      dummy = checkedge4encroach(encloop);
+
+      badsegmentdealloc(encloop);
+      encloop = badsegmenttraverse();
+    }
+  }
+}
+
+#endif /* not CDT_ONLY */
+
+/*****************************************************************************/
+/*                                                                           */
+/*  tallyfaces()   Test every triangle in the mesh for quality measures.     */
+/*                                                                           */
+/*****************************************************************************/
+
+#ifndef CDT_ONLY
+
+void tallyfaces()
+{
+  struct triedge triangleloop;
+
+  if (verbose) {
+    printf("  Making a list of bad triangles.\n");
+  }
+  traversalinit(&triangles);
+  triangleloop.orient = 0;
+  triangleloop.tri = triangletraverse();
+  while (triangleloop.tri != (triangle *) NULL) {
+    /* If the triangle is bad, enqueue it. */
+    testtriangle(&triangleloop);
+    triangleloop.tri = triangletraverse();
+  }
+}
+
+#endif /* not CDT_ONLY */
+
+/*****************************************************************************/
+/*                                                                           */
+/*  findcircumcenter()   Find the circumcenter of a triangle.                */
+/*                                                                           */
+/*  The result is returned both in terms of x-y coordinates and xi-eta       */
+/*  coordinates.  The xi-eta coordinate system is defined in terms of the    */
+/*  triangle:  the origin of the triangle is the origin of the coordinate    */
+/*  system; the destination of the triangle is one unit along the xi axis;   */
+/*  and the apex of the triangle is one unit along the eta axis.             */
+/*                                                                           */
+/*  The return value indicates which edge of the triangle is shortest.       */
+/*                                                                           */
+/*****************************************************************************/
+
+enum circumcenterresult findcircumcenter(torg, tdest, tapex, circumcenter,
+                                         xi, eta)
+point torg;
+point tdest;
+point tapex;
+point circumcenter;
+REAL *xi;
+REAL *eta;
+{
+  REAL xdo, ydo, xao, yao, xad, yad;
+  REAL dodist, aodist, addist;
+  REAL denominator;
+  REAL dx, dy;
+
+  circumcentercount++;
+
+  /* Compute the circumcenter of the triangle. */
+  xdo = tdest[0] - torg[0];
+  ydo = tdest[1] - torg[1];
+  xao = tapex[0] - torg[0];
+  yao = tapex[1] - torg[1];
+  dodist = xdo * xdo + ydo * ydo;
+  aodist = xao * xao + yao * yao;
+  if (noexact) {
+    denominator = 0.5 / (xdo * yao - xao * ydo);
+  } else {
+    /* Use the counterclockwise() routine to ensure a positive (and */
+    /*   reasonably accurate) result, avoiding any possibility of   */
+    /*   division by zero.                                          */
+    denominator = 0.5 / counterclockwise(tdest, tapex, torg);
+    /* Don't count the above as an orientation test. */
+    counterclockcount--;
+  }
+  circumcenter[0] = torg[0] - (ydo * aodist - yao * dodist) * denominator;  
+  circumcenter[1] = torg[1] + (xdo * aodist - xao * dodist) * denominator;  
+
+  /* To interpolate point attributes for the new point inserted at  */
+  /*   the circumcenter, define a coordinate system with a xi-axis, */
+  /*   directed from the triangle's origin to its destination, and  */
+  /*   an eta-axis, directed from its origin to its apex.           */
+  /*   Calculate the xi and eta coordinates of the circumcenter.    */
+  dx = circumcenter[0] - torg[0];
+  dy = circumcenter[1] - torg[1];
+  *xi = (dx * yao - xao * dy) * (2.0 * denominator);
+  *eta = (xdo * dy - dx * ydo) * (2.0 * denominator);
+
+  xad = tapex[0] - tdest[0];
+  yad = tapex[1] - tdest[1];
+  addist = xad * xad + yad * yad;
+  if ((addist < dodist) && (addist < aodist)) {
+    return OPPOSITEORG;
+  } else if (dodist < aodist) {
+    return OPPOSITEAPEX;
+  } else {
+    return OPPOSITEDEST;
+  }
+}
+
+/*****************************************************************************/
+/*                                                                           */
+/*  splittriangle()   Inserts a point at the circumcenter of a triangle.     */
+/*                    Deletes the newly inserted point if it encroaches upon */
+/*                    a segment.                                             */
+/*                                                                           */
+/*****************************************************************************/
+
+#ifndef CDT_ONLY
+
+void splittriangle(badtri)
+struct badface *badtri;
+{
+  point borg, bdest, bapex;
+  point newpoint;
+  REAL xi, eta;
+  enum insertsiteresult success;
+  enum circumcenterresult shortedge;
+  int errorflag;
+  int i;
+
+  org(badtri->badfacetri, borg);
+  dest(badtri->badfacetri, bdest);
+  apex(badtri->badfacetri, bapex);
+  /* Make sure that this triangle is still the same triangle it was      */
+  /*   when it was tested and determined to be of bad quality.           */
+  /*   Subsequent transformations may have made it a different triangle. */
+  if ((borg == badtri->faceorg) && (bdest == badtri->facedest) &&
+      (bapex == badtri->faceapex)) {
+    if (verbose > 1) {
+      printf("  Splitting this triangle at its circumcenter:\n");
+      printf("    (%.12g, %.12g) (%.12g, %.12g) (%.12g, %.12g)\n", borg[0],
+             borg[1], bdest[0], bdest[1], bapex[0], bapex[1]);
+    }
+    errorflag = 0;
+    /* Create a new point at the triangle's circumcenter. */
+    newpoint = (point) poolalloc(&points);
+    shortedge = findcircumcenter(borg, bdest, bapex, newpoint, &xi, &eta);
+    /* Check whether the new point lies on a triangle vertex. */
+    if (((newpoint[0] == borg[0]) && (newpoint[1] == borg[1]))
+        || ((newpoint[0] == bdest[0]) && (newpoint[1] == bdest[1]))
+        || ((newpoint[0] == bapex[0]) && (newpoint[1] == bapex[1]))) {
+      if (!quiet) {
+        printf("Warning:  New point (%.12g, %.12g) falls on existing vertex.\n"
+               , newpoint[0], newpoint[1]);
+        errorflag = 1;
+      }
+      pointdealloc(newpoint);
+    } else {
+      for (i = 2; i < 2 + nextras; i++) {
+        /* Interpolate the point attributes at the circumcenter. */
+        newpoint[i] = borg[i] + xi * (bdest[i] - borg[i])
+                             + eta * (bapex[i] - borg[i]);
+      }
+      /* The new point must be in the interior, and have a marker of zero. */
+      setpointmark(newpoint, 0);
+      /* Ensure that the handle `badtri->badfacetri' represents the shortest */
+      /*   edge of the triangle.  This ensures that the circumcenter must    */
+      /*   fall to the left of this edge, so point location will work.       */
+      if (shortedge == OPPOSITEORG) {
+        lnextself(badtri->badfacetri);
+      } else if (shortedge == OPPOSITEDEST) {
+        lprevself(badtri->badfacetri);
+      }
+      /* Insert the circumcenter, searching from the edge of the triangle, */
+      /*   and maintain the Delaunay property of the triangulation.        */
+      success = insertsite(newpoint, &(badtri->badfacetri),
+                           (struct edge *) NULL, 1, 1);
+      if (success == SUCCESSFULPOINT) {
+        if (steinerleft > 0) {
+          steinerleft--;
+        }
+      } else if (success == ENCROACHINGPOINT) {
+        /* If the newly inserted point encroaches upon a segment, delete it. */
+        deletesite(&(badtri->badfacetri));
+      } else if (success == VIOLATINGPOINT) {
+        /* Failed to insert the new point, but some segment was */
+        /*   marked as being encroached.                        */
+        pointdealloc(newpoint);
+      } else {                                  /* success == DUPLICATEPOINT */
+        /* Failed to insert the new point because a vertex is already there. */
+        if (!quiet) {
+          printf(
+            "Warning:  New point (%.12g, %.12g) falls on existing vertex.\n"
+                 , newpoint[0], newpoint[1]);
+          errorflag = 1;
+        }
+        pointdealloc(newpoint);
+      }
+    }
+    if (errorflag) {
+      if (verbose) {
+        printf("  The new point is at the circumcenter of triangle\n");
+        printf("    (%.12g, %.12g) (%.12g, %.12g) (%.12g, %.12g)\n",
+               borg[0], borg[1], bdest[0], bdest[1], bapex[0], bapex[1]);
+      }
+      printf("This probably means that I am trying to refine triangles\n");
+      printf("  to a smaller size than can be accommodated by the finite\n");
+      printf("  precision of floating point arithmetic.  (You can be\n");
+      printf("  sure of this if I fail to terminate.)\n");
+      precisionerror();
+    }
+  }
+  /* Return the bad triangle to the pool. */
+  pooldealloc(&badtriangles, (VOID *) badtri);
+}
+
+#endif /* not CDT_ONLY */
+
+/*****************************************************************************/
+/*                                                                           */
+/*  enforcequality()   Remove all the encroached edges and bad triangles     */
+/*                     from the triangulation.                               */
+/*                                                                           */
+/*****************************************************************************/
+
+#ifndef CDT_ONLY
+
+void enforcequality()
+{
+  int i;
+
+  if (!quiet) {
+    printf("Adding Steiner points to enforce quality.\n");
+  }
+  /* Initialize the pool of encroached segments. */
+  poolinit(&badsegments, sizeof(struct edge), BADSEGMENTPERBLOCK, POINTER, 0);
+  if (verbose) {
+    printf("  Looking for encroached segments.\n");
+  }
+  /* Test all segments to see if they're encroached. */
+  tallyencs();
+  if (verbose && (badsegments.items > 0)) {
+    printf("  Splitting encroached segments.\n");
+  }
+  /* Note that steinerleft == -1 if an unlimited number */
+  /*   of Steiner points is allowed.                    */
+  while ((badsegments.items > 0) && (steinerleft != 0)) {
+    /* Fix the segments without noting newly encroached segments or   */
+    /*   bad triangles.  The reason we don't want to note newly       */
+    /*   encroached segments is because some encroached segments are  */
+    /*   likely to be noted multiple times, and would then be blindly */
+    /*   split multiple times.  I should fix that some time.          */
+    repairencs(0);
+    /* Now, find all the segments that became encroached while adding */
+    /*   points to split encroached segments.                         */
+    tallyencs();
+  }
+  /* At this point, if we haven't run out of Steiner points, the */
+  /*   triangulation should be (conforming) Delaunay.            */
+
+  /* Next, we worry about enforcing triangle quality. */
+  if ((minangle > 0.0) || vararea || fixedarea) {
+    /* Initialize the pool of bad triangles. */
+    poolinit(&badtriangles, sizeof(struct badface), BADTRIPERBLOCK, POINTER,
+             0);
+    /* Initialize the queues of bad triangles. */
+    for (i = 0; i < 64; i++) {
+      queuefront[i] = (struct badface *) NULL;
+      queuetail[i] = &queuefront[i];
+    }
+    /* Test all triangles to see if they're bad. */
+    tallyfaces();
+    if (verbose) {
+      printf("  Splitting bad triangles.\n");
+    }
+    while ((badtriangles.items > 0) && (steinerleft != 0)) {
+      /* Fix one bad triangle by inserting a point at its circumcenter. */
+      splittriangle(dequeuebadtri());
+      /* Fix any encroached segments that may have resulted.  Record */
+      /*   any new bad triangles or encroached segments that result. */
+      if (badsegments.items > 0) {
+        repairencs(1);
+      }
+    }
+  }
+  /* At this point, if we haven't run out of Steiner points, the */
+  /*   triangulation should be (conforming) Delaunay and have no */
+  /*   low-quality triangles.                                    */
+
+  /* Might we have run out of Steiner points too soon? */
+  if (!quiet && (badsegments.items > 0) && (steinerleft == 0)) {
+    printf("\nWarning:  I ran out of Steiner points, but the mesh has\n");
+    if (badsegments.items == 1) {
+      printf("  an encroached segment, and therefore might not be truly\n");
+    } else {
+      printf("  %ld encroached segments, and therefore might not be truly\n",
+             badsegments.items);
+    }
+    printf("  Delaunay.  If the Delaunay property is important to you,\n");
+    printf("  try increasing the number of Steiner points (controlled by\n");
+    printf("  the -S switch) slightly and try again.\n\n");
+  }
+}
+
+#endif /* not CDT_ONLY */
+
+/**                                                                         **/
+/**                                                                         **/
+/********* Mesh quality maintenance ends here                        *********/
+
+/*****************************************************************************/
+/*                                                                           */
+/*  highorder()   Create extra nodes for quadratic subparametric elements.   */
+/*                                                                           */
+/*****************************************************************************/
+
+void highorder()
+{
+  struct triedge triangleloop, trisym;
+  struct edge checkmark;
+  point newpoint;
+  point torg, tdest;
+  int i;
+  triangle ptr;                         /* Temporary variable used by sym(). */
+  shelle sptr;                      /* Temporary variable used by tspivot(). */
+
+  if (!quiet) {
+    printf("Adding vertices for second-order triangles.\n");
+  }
+  /* The following line ensures that dead items in the pool of nodes    */
+  /*   cannot be allocated for the extra nodes associated with high     */
+  /*   order elements.  This ensures that the primary nodes (at the     */
+  /*   corners of elements) will occur earlier in the output files, and */
+  /*   have lower indices, than the extra nodes.                        */
+  points.deaditemstack = (VOID *) NULL;
+
+  traversalinit(&triangles);
+  triangleloop.tri = triangletraverse();
+  /* To loop over the set of edges, loop over all triangles, and look at   */
+  /*   the three edges of each triangle.  If there isn't another triangle  */
+  /*   adjacent to the edge, operate on the edge.  If there is another     */
+  /*   adjacent triangle, operate on the edge only if the current triangle */
+  /*   has a smaller pointer than its neighbor.  This way, each edge is    */
+  /*   considered only once.                                               */
+  while (triangleloop.tri != (triangle *) NULL) {
+    for (triangleloop.orient = 0; triangleloop.orient < 3;
+         triangleloop.orient++) {
+      sym(triangleloop, trisym);
+      if ((triangleloop.tri < trisym.tri) || (trisym.tri == dummytri)) {
+        org(triangleloop, torg);
+        dest(triangleloop, tdest);
+        /* Create a new node in the middle of the edge.  Interpolate */
+        /*   its attributes.                                         */
+        newpoint = (point) poolalloc(&points);
+        for (i = 0; i < 2 + nextras; i++) {
+          newpoint[i] = 0.5 * (torg[i] + tdest[i]);
+        }
+        /* Set the new node's marker to zero or one, depending on */
+        /*   whether it lies on a boundary.                       */
+        setpointmark(newpoint, trisym.tri == dummytri);
+        if (useshelles) {
+          tspivot(triangleloop, checkmark);
+          /* If this edge is a segment, transfer the marker to the new node. */
+          if (checkmark.sh != dummysh) {
+            setpointmark(newpoint, mark(checkmark));
+          }
+        }
+        if (verbose > 1) {
+          printf("  Creating (%.12g, %.12g).\n", newpoint[0], newpoint[1]);
+        }
+        /* Record the new node in the (one or two) adjacent elements. */
+        triangleloop.tri[highorderindex + triangleloop.orient] =
+                (triangle) newpoint;
+        if (trisym.tri != dummytri) {
+          trisym.tri[highorderindex + trisym.orient] = (triangle) newpoint;
+        }
+      }
+    }
+    triangleloop.tri = triangletraverse();
+  }
+}
+
+/********* File I/O routines begin here                              *********/
+/**                                                                         **/
+/**                                                                         **/
+
+/*****************************************************************************/
+/*                                                                           */
+/*  readline()   Read a nonempty line from a file.                           */
+/*                                                                           */
+/*  A line is considered "nonempty" if it contains something that looks like */
+/*  a number.                                                                */
+/*                                                                           */
+/*****************************************************************************/
+
+#ifndef TRILIBRARY
+
+char *readline(string, infile, infilename)
+char *string;
+FILE *infile;
+char *infilename;
+{
+  char *result;
+
+  /* Search for something that looks like a number. */
+  do {
+    result = fgets(string, INPUTLINESIZE, infile);
+    if (result == (char *) NULL) {
+      printf("  Error:  Unexpected end of file in %s.\n", infilename);
+      exit(1);
+    }
+    /* Skip anything that doesn't look like a number, a comment, */
+    /*   or the end of a line.                                   */
+    while ((*result != '\0') && (*result != '#')
+           && (*result != '.') && (*result != '+') && (*result != '-')
+           && ((*result < '0') || (*result > '9'))) {
+      result++;
+    }
+  /* If it's a comment or end of line, read another line and try again. */
+  } while ((*result == '#') || (*result == '\0'));
+  return result;
+}
+
+#endif /* not TRILIBRARY */
+
+/*****************************************************************************/
+/*                                                                           */
+/*  findfield()   Find the next field of a string.                           */
+/*                                                                           */
+/*  Jumps past the current field by searching for whitespace, then jumps     */
+/*  past the whitespace to find the next field.                              */
+/*                                                                           */
+/*****************************************************************************/
+
+#ifndef TRILIBRARY
+
+char *findfield(string)
+char *string;
+{
+  char *result;
+
+  result = string;
+  /* Skip the current field.  Stop upon reaching whitespace. */
+  while ((*result != '\0') && (*result != '#')
+         && (*result != ' ') && (*result != '\t')) {
+    result++;
+  }
+  /* Now skip the whitespace and anything else that doesn't look like a */
+  /*   number, a comment, or the end of a line.                         */
+  while ((*result != '\0') && (*result != '#')
+         && (*result != '.') && (*result != '+') && (*result != '-')
+         && ((*result < '0') || (*result > '9'))) {
+    result++;
+  }
+  /* Check for a comment (prefixed with `#'). */
+  if (*result == '#') {
+    *result = '\0';
+  }
+  return result;
+}
+
+#endif /* not TRILIBRARY */
+
+/*****************************************************************************/
+/*                                                                           */
+/*  readnodes()   Read the points from a file, which may be a .node or .poly */
+/*                file.                                                      */
+/*                                                                           */
+/*****************************************************************************/
+
+#ifndef TRILIBRARY
+
+void readnodes(nodefilename, polyfilename, polyfile)
+char *nodefilename;
+char *polyfilename;
+FILE **polyfile;
+{
+  FILE *infile;
+  point pointloop;
+  char inputline[INPUTLINESIZE];
+  char *stringptr;
+  char *infilename;
+  REAL x, y;
+  int firstnode;
+  int nodemarkers;
+  int currentmarker;
+  int i, j;
+
+  if (poly) {
+    /* Read the points from a .poly file. */
+    if (!quiet) {
+      printf("Opening %s.\n", polyfilename);
+    }
+    *polyfile = fopen(polyfilename, "r");
+    if (*polyfile == (FILE *) NULL) {
+      printf("  Error:  Cannot access file %s.\n", polyfilename);
+      exit(1);
+    }
+    /* Read number of points, number of dimensions, number of point */
+    /*   attributes, and number of boundary markers.                */
+    stringptr = readline(inputline, *polyfile, polyfilename);
+    inpoints = (int) strtol (stringptr, &stringptr, 0);
+    stringptr = findfield(stringptr);
+    if (*stringptr == '\0') {
+      mesh_dim = 2;
+    } else {
+      mesh_dim = (int) strtol (stringptr, &stringptr, 0);
+    }
+    stringptr = findfield(stringptr);
+    if (*stringptr == '\0') {
+      nextras = 0;
+    } else {
+      nextras = (int) strtol (stringptr, &stringptr, 0);
+    }
+    stringptr = findfield(stringptr);
+    if (*stringptr == '\0') {
+      nodemarkers = 0;
+    } else {
+      nodemarkers = (int) strtol (stringptr, &stringptr, 0);
+    }
+    if (inpoints > 0) {
+      infile = *polyfile;
+      infilename = polyfilename;
+      readnodefile = 0;
+    } else {
+      /* If the .poly file claims there are zero points, that means that */
+      /*   the points should be read from a separate .node file.         */
+      readnodefile = 1;
+      infilename = innodefilename;
+    }
+  } else {
+    readnodefile = 1;
+    infilename = innodefilename;
+    *polyfile = (FILE *) NULL;
+  }
+
+  if (readnodefile) {
+    /* Read the points from a .node file. */
+    if (!quiet) {
+      printf("Opening %s.\n", innodefilename);
+    }
+    infile = fopen(innodefilename, "r");
+    if (infile == (FILE *) NULL) {
+      printf("  Error:  Cannot access file %s.\n", innodefilename);
+      exit(1);
+    }
+    /* Read number of points, number of dimensions, number of point */
+    /*   attributes, and number of boundary markers.                */
+    stringptr = readline(inputline, infile, innodefilename);
+    inpoints = (int) strtol (stringptr, &stringptr, 0);
+    stringptr = findfield(stringptr);
+    if (*stringptr == '\0') {
+      mesh_dim = 2;
+    } else {
+      mesh_dim = (int) strtol (stringptr, &stringptr, 0);
+    }
+    stringptr = findfield(stringptr);
+    if (*stringptr == '\0') {
+      nextras = 0;
+    } else {
+      nextras = (int) strtol (stringptr, &stringptr, 0);
+    }
+    stringptr = findfield(stringptr);
+    if (*stringptr == '\0') {
+      nodemarkers = 0;
+    } else {
+      nodemarkers = (int) strtol (stringptr, &stringptr, 0);
+    }
+  }
+
+  if (inpoints < 3) {
+    printf("Error:  Input must have at least three input points.\n");
+    exit(1);
+  }
+  if (mesh_dim != 2) {
+    printf("Error:  Triangle only works with two-dimensional meshes.\n");
+    exit(1);
+  }
+
+  initializepointpool();
+
+  /* Read the points. */
+  for (i = 0; i < inpoints; i++) {
+    pointloop = (point) poolalloc(&points);
+    stringptr = readline(inputline, infile, infilename);
+    if (i == 0) {
+      firstnode = (int) strtol (stringptr, &stringptr, 0);
+      if ((firstnode == 0) || (firstnode == 1)) {
+        firstnumber = firstnode;
+      }
+    }
+    stringptr = findfield(stringptr);
+    if (*stringptr == '\0') {
+      printf("Error:  Point %d has no x coordinate.\n", firstnumber + i);
+      exit(1);
+    }
+    x = (REAL) strtod(stringptr, &stringptr);
+    stringptr = findfield(stringptr);
+    if (*stringptr == '\0') {
+      printf("Error:  Point %d has no y coordinate.\n", firstnumber + i);
+      exit(1);
+    }
+    y = (REAL) strtod(stringptr, &stringptr);
+    pointloop[0] = x;
+    pointloop[1] = y;
+    /* Read the point attributes. */
+    for (j = 2; j < 2 + nextras; j++) {
+      stringptr = findfield(stringptr);
+      if (*stringptr == '\0') {
+        pointloop[j] = 0.0;
+      } else {
+        pointloop[j] = (REAL) strtod(stringptr, &stringptr);
+      }
+    }
+    if (nodemarkers) {
+      /* Read a point marker. */
+      stringptr = findfield(stringptr);
+      if (*stringptr == '\0') {
+        setpointmark(pointloop, 0);
+      } else {
+        currentmarker = (int) strtol (stringptr, &stringptr, 0);
+        setpointmark(pointloop, currentmarker);
+      }
+    } else {
+      /* If no markers are specified in the file, they default to zero. */
+      setpointmark(pointloop, 0);
+    }
+    /* Determine the smallest and largest x and y coordinates. */
+    if (i == 0) {
+      xmin = xmax = x;
+      ymin = ymax = y;
+    } else {
+      xmin = (x < xmin) ? x : xmin;
+      xmax = (x > xmax) ? x : xmax;
+      ymin = (y < ymin) ? y : ymin;
+      ymax = (y > ymax) ? y : ymax;
+    }
+  }
+  if (readnodefile) {
+    fclose(infile);
+  }
+
+  /* Nonexistent x value used as a flag to mark circle events in sweepline */
+  /*   Delaunay algorithm.                                                 */
+  xminextreme = 10 * xmin - 9 * xmax;
+}
+
+#endif /* not TRILIBRARY */
+
+/*****************************************************************************/
+/*                                                                           */
+/*  transfernodes()   Read the points from memory.                           */
+/*                                                                           */
+/*****************************************************************************/
+
+#ifdef TRILIBRARY
+
+void transfernodes(pointlist, pointattriblist, pointmarkerlist, numberofpoints,
+                   numberofpointattribs)
+REAL *pointlist;
+REAL *pointattriblist;
+int *pointmarkerlist;
+int numberofpoints;
+int numberofpointattribs;
+{
+  point pointloop;
+  REAL x, y;
+  int i, j;
+  int coordindex;
+  int attribindex;
+
+  inpoints = numberofpoints;
+  mesh_dim = 2;
+  nextras = numberofpointattribs;
+  readnodefile = 0;
+  if (inpoints < 3) {
+    printf("Error:  Input must have at least three input points.\n");
+    exit(1);
+  }
+
+  initializepointpool();
+
+  /* Read the points. */
+  coordindex = 0;
+  attribindex = 0;
+  for (i = 0; i < inpoints; i++) {
+    pointloop = (point) poolalloc(&points);
+    /* Read the point coordinates. */
+    x = pointloop[0] = pointlist[coordindex++];
+    y = pointloop[1] = pointlist[coordindex++];
+    /* Read the point attributes. */
+    for (j = 0; j < numberofpointattribs; j++) {
+      pointloop[2 + j] = pointattriblist[attribindex++];
+    }
+    if (pointmarkerlist != (int *) NULL) {
+      /* Read a point marker. */
+      setpointmark(pointloop, pointmarkerlist[i]);
+    } else {
+      /* If no markers are specified, they default to zero. */
+      setpointmark(pointloop, 0);
+    }
+    x = pointloop[0];
+    y = pointloop[1];
+    /* Determine the smallest and largest x and y coordinates. */
+    if (i == 0) {
+      xmin = xmax = x;
+      ymin = ymax = y;
+    } else {
+      xmin = (x < xmin) ? x : xmin;
+      xmax = (x > xmax) ? x : xmax;
+      ymin = (y < ymin) ? y : ymin;
+      ymax = (y > ymax) ? y : ymax;
+    }
+  }
+
+  /* Nonexistent x value used as a flag to mark circle events in sweepline */
+  /*   Delaunay algorithm.                                                 */
+  xminextreme = 10 * xmin - 9 * xmax;
+}
+
+#endif /* TRILIBRARY */
+
+/*****************************************************************************/
+/*                                                                           */
+/*  readholes()   Read the holes, and possibly regional attributes and area  */
+/*                constraints, from a .poly file.                            */
+/*                                                                           */
+/*****************************************************************************/
+
+#ifndef TRILIBRARY
+
+void readholes(polyfile, polyfilename, hlist, holes, rlist, regions)
+FILE *polyfile;
+char *polyfilename;
+REAL **hlist;
+int *holes;
+REAL **rlist;
+int *regions;
+{
+  REAL *holelist;
+  REAL *regionlist;
+  char inputline[INPUTLINESIZE];
+  char *stringptr;
+  int index;
+  int i;
+
+  /* Read the holes. */
+  stringptr = readline(inputline, polyfile, polyfilename);
+  *holes = (int) strtol (stringptr, &stringptr, 0);
+  if (*holes > 0) {
+    holelist = (REAL *) malloc(2 * *holes * sizeof(REAL));
+    *hlist = holelist;
+    if (holelist == (REAL *) NULL) {
+      printf("Error:  Out of memory.\n");
+      exit(1);
+    }
+    for (i = 0; i < 2 * *holes; i += 2) {
+      stringptr = readline(inputline, polyfile, polyfilename);
+      stringptr = findfield(stringptr);
+      if (*stringptr == '\0') {
+        printf("Error:  Hole %d has no x coordinate.\n",
+               firstnumber + (i >> 1));
+        exit(1);
+      } else {
+        holelist[i] = (REAL) strtod(stringptr, &stringptr);
+      }
+      stringptr = findfield(stringptr);
+      if (*stringptr == '\0') {
+        printf("Error:  Hole %d has no y coordinate.\n",
+               firstnumber + (i >> 1));
+        exit(1);
+      } else {
+        holelist[i + 1] = (REAL) strtod(stringptr, &stringptr);
+      }
+    }
+  } else {
+    *hlist = (REAL *) NULL;
+  }
+
+#ifndef CDT_ONLY
+  if ((regionattrib || vararea) && !refine) {
+    /* Read the area constraints. */
+    stringptr = readline(inputline, polyfile, polyfilename);
+    *regions = (int) strtol (stringptr, &stringptr, 0);
+    if (*regions > 0) {
+      regionlist = (REAL *) malloc(4 * *regions * sizeof(REAL));
+      *rlist = regionlist;
+      if (regionlist == (REAL *) NULL) {
+        printf("Error:  Out of memory.\n");
+        exit(1);
+      }
+      index = 0;
+      for (i = 0; i < *regions; i++) {
+        stringptr = readline(inputline, polyfile, polyfilename);
+        stringptr = findfield(stringptr);
+        if (*stringptr == '\0') {
+          printf("Error:  Region %d has no x coordinate.\n",
+                 firstnumber + i);
+          exit(1);
+        } else {
+          regionlist[index++] = (REAL) strtod(stringptr, &stringptr);
+        }
+        stringptr = findfield(stringptr);
+        if (*stringptr == '\0') {
+          printf("Error:  Region %d has no y coordinate.\n",
+                 firstnumber + i);
+          exit(1);
+        } else {
+          regionlist[index++] = (REAL) strtod(stringptr, &stringptr);
+        }
+        stringptr = findfield(stringptr);
+        if (*stringptr == '\0') {
+          printf(
+            "Error:  Region %d has no region attribute or area constraint.\n",
+                 firstnumber + i);
+          exit(1);
+        } else {
+          regionlist[index++] = (REAL) strtod(stringptr, &stringptr);
+        }
+        stringptr = findfield(stringptr);
+        if (*stringptr == '\0') {
+          regionlist[index] = regionlist[index - 1];
+        } else {
+          regionlist[index] = (REAL) strtod(stringptr, &stringptr);
+        }
+        index++;
+      }
+    }
+  } else {
+    /* Set `*regions' to zero to avoid an accidental free() later. */
+    *regions = 0;
+    *rlist = (REAL *) NULL;
+  }
+#endif /* not CDT_ONLY */
+
+  fclose(polyfile);
+}
+
+#endif /* not TRILIBRARY */
+
+/*****************************************************************************/
+/*                                                                           */
+/*  finishfile()   Write the command line to the output file so the user     */
+/*                 can remember how the file was generated.  Close the file. */
+/*                                                                           */
+/*****************************************************************************/
+
+#ifndef TRILIBRARY
+
+void finishfile(outfile, argc, argv)
+FILE *outfile;
+int argc;
+char **argv;
+{
+  int i;
+
+  fprintf(outfile, "# Generated by");
+  for (i = 0; i < argc; i++) {
+    fprintf(outfile, " ");
+    fputs(argv[i], outfile);
+  }
+  fprintf(outfile, "\n");
+  fclose(outfile);
+}
+
+#endif /* not TRILIBRARY */
+
+/*****************************************************************************/
+/*                                                                           */
+/*  writenodes()   Number the points and write them to a .node file.         */
+/*                                                                           */
+/*  To save memory, the point numbers are written over the shell markers     */
+/*  after the points are written to a file.                                  */
+/*                                                                           */
+/*****************************************************************************/
+
+#ifdef TRILIBRARY
+
+void writenodes(pointlist, pointattriblist, pointmarkerlist)
+REAL **pointlist;
+REAL **pointattriblist;
+int **pointmarkerlist;
+
+#else /* not TRILIBRARY */
+
+void writenodes(nodefilename, argc, argv)
+char *nodefilename;
+int argc;
+char **argv;
+
+#endif /* not TRILIBRARY */
+
+{
+#ifdef TRILIBRARY
+  REAL *plist;
+  REAL *palist;
+  int *pmlist;
+  int coordindex;
+  int attribindex;
+#else /* not TRILIBRARY */
+  FILE *outfile;
+#endif /* not TRILIBRARY */
+  point pointloop;
+  int pointnumber;
+  int i;
+
+#ifdef TRILIBRARY
+  if (!quiet) {
+    printf("Writing points.\n");
+  }
+  /* Allocate memory for output points if necessary. */
+  if (*pointlist == (REAL *) NULL) {
+    *pointlist = (REAL *) malloc(points.items * 2 * sizeof(REAL));
+    if (*pointlist == (REAL *) NULL) {
+      printf("Error:  Out of memory.\n");
+      exit(1);
+    }
+  }
+  /* Allocate memory for output point attributes if necessary. */
+  if ((nextras > 0) && (*pointattriblist == (REAL *) NULL)) {
+    *pointattriblist = (REAL *) malloc(points.items * nextras * sizeof(REAL));
+    if (*pointattriblist == (REAL *) NULL) {
+      printf("Error:  Out of memory.\n");
+      exit(1);
+    }
+  }
+  /* Allocate memory for output point markers if necessary. */
+  if (!nobound && (*pointmarkerlist == (int *) NULL)) {
+    *pointmarkerlist = (int *) malloc(points.items * sizeof(int));
+    if (*pointmarkerlist == (int *) NULL) {
+      printf("Error:  Out of memory.\n");
+      exit(1);
+    }
+  }
+  plist = *pointlist;
+  palist = *pointattriblist;
+  pmlist = *pointmarkerlist;
+  coordindex = 0;
+  attribindex = 0;
+#else /* not TRILIBRARY */
+  if (!quiet) {
+    printf("Writing %s.\n", nodefilename);
+  }
+  outfile = fopen(nodefilename, "w");
+  if (outfile == (FILE *) NULL) {
+    printf("  Error:  Cannot create file %s.\n", nodefilename);
+    exit(1);
+  }
+  /* Number of points, number of dimensions, number of point attributes, */
+  /*   and number of boundary markers (zero or one).                     */
+  fprintf(outfile, "%ld  %d  %d  %d\n", points.items, mesh_dim, nextras,
+          1 - nobound);
+#endif /* not TRILIBRARY */
+
+  traversalinit(&points);
+  pointloop = pointtraverse();
+  pointnumber = firstnumber;
+  while (pointloop != (point) NULL) {
+#ifdef TRILIBRARY
+    /* X and y coordinates. */
+    plist[coordindex++] = pointloop[0];
+    plist[coordindex++] = pointloop[1];
+    /* Point attributes. */
+    for (i = 0; i < nextras; i++) {
+      palist[attribindex++] = pointloop[2 + i];
+    }
+    if (!nobound) {
+      /* Copy the boundary marker. */
+      pmlist[pointnumber - firstnumber] = pointmark(pointloop);
+    }
+#else /* not TRILIBRARY */
+    /* Point number, x and y coordinates. */
+    fprintf(outfile, "%4d    %.17g  %.17g", pointnumber, pointloop[0],
+            pointloop[1]);
+    for (i = 0; i < nextras; i++) {
+      /* Write an attribute. */
+      fprintf(outfile, "  %.17g", pointloop[i + 2]);
+    }
+    if (nobound) {
+      fprintf(outfile, "\n");
+    } else {
+      /* Write the boundary marker. */
+      fprintf(outfile, "    %d\n", pointmark(pointloop));
+    }
+#endif /* not TRILIBRARY */
+
+    setpointmark(pointloop, pointnumber);
+    pointloop = pointtraverse();
+    pointnumber++;
+  }
+
+#ifndef TRILIBRARY
+  finishfile(outfile, argc, argv);
+#endif /* not TRILIBRARY */
+}
+
+/*****************************************************************************/
+/*                                                                           */
+/*  numbernodes()   Number the points.                                       */
+/*                                                                           */
+/*  Each point is assigned a marker equal to its number.                     */
+/*                                                                           */
+/*  Used when writenodes() is not called because no .node file is written.   */
+/*                                                                           */
+/*****************************************************************************/
+
+void numbernodes()
+{
+  point pointloop;
+  int pointnumber;
+
+  traversalinit(&points);
+  pointloop = pointtraverse();
+  pointnumber = firstnumber;
+  while (pointloop != (point) NULL) {
+    setpointmark(pointloop, pointnumber);
+    pointloop = pointtraverse();
+    pointnumber++;
+  }
+}
+
+/*****************************************************************************/
+/*                                                                           */
+/*  writeelements()   Write the triangles to an .ele file.                   */
+/*                                                                           */
+/*****************************************************************************/
+
+#ifdef TRILIBRARY
+
+void writeelements(trianglelist, triangleattriblist)
+int **trianglelist;
+REAL **triangleattriblist;
+
+#else /* not TRILIBRARY */
+
+void writeelements(elefilename, argc, argv)
+char *elefilename;
+int argc;
+char **argv;
+
+#endif /* not TRILIBRARY */
+
+{
+#ifdef TRILIBRARY
+  int *tlist;
+  REAL *talist;
+  int pointindex;
+  int attribindex;
+#else /* not TRILIBRARY */
+  FILE *outfile;
+#endif /* not TRILIBRARY */
+  struct triedge triangleloop;
+  point p1, p2, p3;
+  point mid1, mid2, mid3;
+  int elementnumber;
+  int i;
+
+#ifdef TRILIBRARY
+  if (!quiet) {
+    printf("Writing triangles.\n");
+  }
+  /* Allocate memory for output triangles if necessary. */
+  if (*trianglelist == (int *) NULL) {
+    *trianglelist = (int *) malloc(triangles.items *
+                               ((order + 1) * (order + 2) / 2) * sizeof(int));
+    if (*trianglelist == (int *) NULL) {
+      printf("Error:  Out of memory.\n");
+      exit(1);
+    }
+  }
+  /* Allocate memory for output triangle attributes if necessary. */
+  if ((eextras > 0) && (*triangleattriblist == (REAL *) NULL)) {
+    *triangleattriblist = (REAL *) malloc(triangles.items * eextras *
+                                          sizeof(REAL));
+    if (*triangleattriblist == (REAL *) NULL) {
+      printf("Error:  Out of memory.\n");
+      exit(1);
+    }
+  }
+  tlist = *trianglelist;
+  talist = *triangleattriblist;
+  pointindex = 0;
+  attribindex = 0;
+#else /* not TRILIBRARY */
+  if (!quiet) {
+    printf("Writing %s.\n", elefilename);
+  }
+  outfile = fopen(elefilename, "w");
+  if (outfile == (FILE *) NULL) {
+    printf("  Error:  Cannot create file %s.\n", elefilename);
+    exit(1);
+  }
+  /* Number of triangles, points per triangle, attributes per triangle. */
+  fprintf(outfile, "%ld  %d  %d\n", triangles.items,
+          (order + 1) * (order + 2) / 2, eextras);
+#endif /* not TRILIBRARY */
+
+  traversalinit(&triangles);
+  triangleloop.tri = triangletraverse();
+  triangleloop.orient = 0;
+  elementnumber = firstnumber;
+  while (triangleloop.tri != (triangle *) NULL) {
+    org(triangleloop, p1);
+    dest(triangleloop, p2);
+    apex(triangleloop, p3);
+    if (order == 1) {
+#ifdef TRILIBRARY
+      tlist[pointindex++] = pointmark(p1);
+      tlist[pointindex++] = pointmark(p2);
+      tlist[pointindex++] = pointmark(p3);
+#else /* not TRILIBRARY */
+      /* Triangle number, indices for three points. */
+      fprintf(outfile, "%4d    %4d  %4d  %4d", elementnumber,
+              pointmark(p1), pointmark(p2), pointmark(p3));
+#endif /* not TRILIBRARY */
+    } else {
+      mid1 = (point) triangleloop.tri[highorderindex + 1];
+      mid2 = (point) triangleloop.tri[highorderindex + 2];
+      mid3 = (point) triangleloop.tri[highorderindex];
+#ifdef TRILIBRARY
+      tlist[pointindex++] = pointmark(p1);
+      tlist[pointindex++] = pointmark(p2);
+      tlist[pointindex++] = pointmark(p3);
+      tlist[pointindex++] = pointmark(mid1);
+      tlist[pointindex++] = pointmark(mid2);
+      tlist[pointindex++] = pointmark(mid3);
+#else /* not TRILIBRARY */
+      /* Triangle number, indices for six points. */
+      fprintf(outfile, "%4d    %4d  %4d  %4d  %4d  %4d  %4d", elementnumber,
+              pointmark(p1), pointmark(p2), pointmark(p3), pointmark(mid1),
+              pointmark(mid2), pointmark(mid3));
+#endif /* not TRILIBRARY */
+    }
+
+#ifdef TRILIBRARY
+    for (i = 0; i < eextras; i++) {
+      talist[attribindex++] = elemattribute(triangleloop, i);
+    }
+#else /* not TRILIBRARY */
+    for (i = 0; i < eextras; i++) {
+      fprintf(outfile, "  %.17g", elemattribute(triangleloop, i));
+    }
+    fprintf(outfile, "\n");
+#endif /* not TRILIBRARY */
+
+    triangleloop.tri = triangletraverse();
+    elementnumber++;
+  }
+
+#ifndef TRILIBRARY
+  finishfile(outfile, argc, argv);
+#endif /* not TRILIBRARY */
+}
+
+/*****************************************************************************/
+/*                                                                           */
+/*  writepoly()   Write the segments and holes to a .poly file.              */
+/*                                                                           */
+/*****************************************************************************/
+
+#ifdef TRILIBRARY
+
+void writepoly(segmentlist, segmentmarkerlist)
+int **segmentlist;
+int **segmentmarkerlist;
+
+#else /* not TRILIBRARY */
+
+void writepoly(polyfilename, holelist, holes, regionlist, regions, argc, argv)
+char *polyfilename;
+REAL *holelist;
+int holes;
+REAL *regionlist;
+int regions;
+int argc;
+char **argv;
+
+#endif /* not TRILIBRARY */
+
+{
+#ifdef TRILIBRARY
+  int *slist;
+  int *smlist;
+  int index;
+#else /* not TRILIBRARY */
+  FILE *outfile;
+  int i;
+#endif /* not TRILIBRARY */
+  struct edge shelleloop;
+  point endpoint1, endpoint2;
+  int shellenumber;
+
+#ifdef TRILIBRARY
+  if (!quiet) {
+    printf("Writing segments.\n");
+  }
+  /* Allocate memory for output segments if necessary. */
+  if (*segmentlist == (int *) NULL) {
+    *segmentlist = (int *) malloc(shelles.items * 2 * sizeof(int));
+    if (*segmentlist == (int *) NULL) {
+      printf("Error:  Out of memory.\n");
+      exit(1);
+    }
+  }
+  /* Allocate memory for output segment markers if necessary. */
+  if (!nobound && (*segmentmarkerlist == (int *) NULL)) {
+    *segmentmarkerlist = (int *) malloc(shelles.items * sizeof(int));
+    if (*segmentmarkerlist == (int *) NULL) {
+      printf("Error:  Out of memory.\n");
+      exit(1);
+    }
+  }
+  slist = *segmentlist;
+  smlist = *segmentmarkerlist;
+  index = 0;
+#else /* not TRILIBRARY */
+  if (!quiet) {
+    printf("Writing %s.\n", polyfilename);
+  }
+  outfile = fopen(polyfilename, "w");
+  if (outfile == (FILE *) NULL) {
+    printf("  Error:  Cannot create file %s.\n", polyfilename);
+    exit(1);
+  }
+  /* The zero indicates that the points are in a separate .node file. */
+  /*   Followed by number of dimensions, number of point attributes,  */
+  /*   and number of boundary markers (zero or one).                  */
+  fprintf(outfile, "%d  %d  %d  %d\n", 0, mesh_dim, nextras, 1 - nobound);
+  /* Number of segments, number of boundary markers (zero or one). */
+  fprintf(outfile, "%ld  %d\n", shelles.items, 1 - nobound);
+#endif /* not TRILIBRARY */
+
+  traversalinit(&shelles);
+  shelleloop.sh = shelletraverse();
+  shelleloop.shorient = 0;
+  shellenumber = firstnumber;
+  while (shelleloop.sh != (shelle *) NULL) {
+    sorg(shelleloop, endpoint1);
+    sdest(shelleloop, endpoint2);
+#ifdef TRILIBRARY
+    /* Copy indices of the segment's two endpoints. */
+    slist[index++] = pointmark(endpoint1);
+    slist[index++] = pointmark(endpoint2);
+    if (!nobound) {
+      /* Copy the boundary marker. */
+      smlist[shellenumber - firstnumber] = mark(shelleloop);
+    }
+#else /* not TRILIBRARY */
+    /* Segment number, indices of its two endpoints, and possibly a marker. */
+    if (nobound) {
+      fprintf(outfile, "%4d    %4d  %4d\n", shellenumber,
+              pointmark(endpoint1), pointmark(endpoint2));
+    } else {
+      fprintf(outfile, "%4d    %4d  %4d    %4d\n", shellenumber,
+              pointmark(endpoint1), pointmark(endpoint2), mark(shelleloop));
+    }
+#endif /* not TRILIBRARY */
+
+    shelleloop.sh = shelletraverse();
+    shellenumber++;
+  }
+
+#ifndef TRILIBRARY
+#ifndef CDT_ONLY
+  fprintf(outfile, "%d\n", holes);
+  if (holes > 0) {
+    for (i = 0; i < holes; i++) {
+      /* Hole number, x and y coordinates. */
+      fprintf(outfile, "%4d   %.17g  %.17g\n", firstnumber + i,
+              holelist[2 * i], holelist[2 * i + 1]);
+    }
+  }
+  if (regions > 0) {
+    fprintf(outfile, "%d\n", regions);
+    for (i = 0; i < regions; i++) {
+      /* Region number, x and y coordinates, attribute, maximum area. */
+      fprintf(outfile, "%4d   %.17g  %.17g  %.17g  %.17g\n", firstnumber + i,
+              regionlist[4 * i], regionlist[4 * i + 1],
+              regionlist[4 * i + 2], regionlist[4 * i + 3]);
+    }
+  }
+#endif /* not CDT_ONLY */
+
+  finishfile(outfile, argc, argv);
+#endif /* not TRILIBRARY */
+}
+
+/*****************************************************************************/
+/*                                                                           */
+/*  writeedges()   Write the edges to a .edge file.                          */
+/*                                                                           */
+/*****************************************************************************/
+
+#ifdef TRILIBRARY
+
+void writeedges(edgelist, edgemarkerlist)
+int **edgelist;
+int **edgemarkerlist;
+
+#else /* not TRILIBRARY */
+
+void writeedges(edgefilename, argc, argv)
+char *edgefilename;
+int argc;
+char **argv;
+
+#endif /* not TRILIBRARY */
+
+{
+#ifdef TRILIBRARY
+  int *elist;
+  int *emlist;
+  int index;
+#else /* not TRILIBRARY */
+  FILE *outfile;
+#endif /* not TRILIBRARY */
+  struct triedge triangleloop, trisym;
+  struct edge checkmark;
+  point p1, p2;
+  int edgenumber;
+  triangle ptr;                         /* Temporary variable used by sym(). */
+  shelle sptr;                      /* Temporary variable used by tspivot(). */
+
+#ifdef TRILIBRARY
+  if (!quiet) {
+    printf("Writing edges.\n");
+  }
+  /* Allocate memory for edges if necessary. */
+  if (*edgelist == (int *) NULL) {
+    *edgelist = (int *) malloc(edges * 2 * sizeof(int));
+    if (*edgelist == (int *) NULL) {
+      printf("Error:  Out of memory.\n");
+      exit(1);
+    }
+  }
+  /* Allocate memory for edge markers if necessary. */
+  if (!nobound && (*edgemarkerlist == (int *) NULL)) {
+    *edgemarkerlist = (int *) malloc(edges * sizeof(int));
+    if (*edgemarkerlist == (int *) NULL) {
+      printf("Error:  Out of memory.\n");
+      exit(1);
+    }
+  }
+  elist = *edgelist;
+  emlist = *edgemarkerlist;
+  index = 0;
+#else /* not TRILIBRARY */
+  if (!quiet) {
+    printf("Writing %s.\n", edgefilename);
+  }
+  outfile = fopen(edgefilename, "w");
+  if (outfile == (FILE *) NULL) {
+    printf("  Error:  Cannot create file %s.\n", edgefilename);
+    exit(1);
+  }
+  /* Number of edges, number of boundary markers (zero or one). */
+  fprintf(outfile, "%ld  %d\n", edges, 1 - nobound);
+#endif /* not TRILIBRARY */
+
+  traversalinit(&triangles);
+  triangleloop.tri = triangletraverse();
+  edgenumber = firstnumber;
+  /* To loop over the set of edges, loop over all triangles, and look at   */
+  /*   the three edges of each triangle.  If there isn't another triangle  */
+  /*   adjacent to the edge, operate on the edge.  If there is another     */
+  /*   adjacent triangle, operate on the edge only if the current triangle */
+  /*   has a smaller pointer than its neighbor.  This way, each edge is    */
+  /*   considered only once.                                               */
+  while (triangleloop.tri != (triangle *) NULL) {
+    for (triangleloop.orient = 0; triangleloop.orient < 3;
+         triangleloop.orient++) {
+      sym(triangleloop, trisym);
+      if ((triangleloop.tri < trisym.tri) || (trisym.tri == dummytri)) {
+        org(triangleloop, p1);
+        dest(triangleloop, p2);
+#ifdef TRILIBRARY
+        elist[index++] = pointmark(p1);
+        elist[index++] = pointmark(p2);
+#endif /* TRILIBRARY */
+        if (nobound) {
+#ifndef TRILIBRARY
+          /* Edge number, indices of two endpoints. */
+          fprintf(outfile, "%4d   %d  %d\n", edgenumber,
+                  pointmark(p1), pointmark(p2));
+#endif /* not TRILIBRARY */
+        } else {
+          /* Edge number, indices of two endpoints, and a boundary marker. */
+          /*   If there's no shell edge, the boundary marker is zero.      */
+          if (useshelles) {
+            tspivot(triangleloop, checkmark);
+            if (checkmark.sh == dummysh) {
+#ifdef TRILIBRARY
+              emlist[edgenumber - firstnumber] = 0;
+#else /* not TRILIBRARY */
+              fprintf(outfile, "%4d   %d  %d  %d\n", edgenumber,
+                      pointmark(p1), pointmark(p2), 0);
+#endif /* not TRILIBRARY */
+            } else {
+#ifdef TRILIBRARY
+              emlist[edgenumber - firstnumber] = mark(checkmark);
+#else /* not TRILIBRARY */
+              fprintf(outfile, "%4d   %d  %d  %d\n", edgenumber,
+                      pointmark(p1), pointmark(p2), mark(checkmark));
+#endif /* not TRILIBRARY */
+            }
+          } else {
+#ifdef TRILIBRARY
+            emlist[edgenumber - firstnumber] = trisym.tri == dummytri;
+#else /* not TRILIBRARY */
+            fprintf(outfile, "%4d   %d  %d  %d\n", edgenumber,
+                    pointmark(p1), pointmark(p2), trisym.tri == dummytri);
+#endif /* not TRILIBRARY */
+          }
+        }
+        edgenumber++;
+      }
+    }
+    triangleloop.tri = triangletraverse();
+  }
+
+#ifndef TRILIBRARY
+  finishfile(outfile, argc, argv);
+#endif /* not TRILIBRARY */
+}
+
+/*****************************************************************************/
+/*                                                                           */
+/*  writevoronoi()   Write the Voronoi diagram to a .v.node and .v.edge      */
+/*                   file.                                                   */
+/*                                                                           */
+/*  The Voronoi diagram is the geometric dual of the Delaunay triangulation. */
+/*  Hence, the Voronoi vertices are listed by traversing the Delaunay        */
+/*  triangles, and the Voronoi edges are listed by traversing the Delaunay   */
+/*  edges.                                                                   */
+/*                                                                           */
+/*  WARNING:  In order to assign numbers to the Voronoi vertices, this       */
+/*  procedure messes up the shell edges or the extra nodes of every          */
+/*  element.  Hence, you should call this procedure last.                    */
+/*                                                                           */
+/*****************************************************************************/
+
+#ifdef TRILIBRARY
+
+void writevoronoi(vpointlist, vpointattriblist, vpointmarkerlist, vedgelist,
+                  vedgemarkerlist, vnormlist)
+REAL **vpointlist;
+REAL **vpointattriblist;
+int **vpointmarkerlist;
+int **vedgelist;
+int **vedgemarkerlist;
+REAL **vnormlist;
+
+#else /* not TRILIBRARY */
+
+void writevoronoi(vnodefilename, vedgefilename, argc, argv)
+char *vnodefilename;
+char *vedgefilename;
+int argc;
+char **argv;
+
+#endif /* not TRILIBRARY */
+
+{
+#ifdef TRILIBRARY
+  REAL *plist;
+  REAL *palist;
+  int *elist;
+  REAL *normlist;
+  int coordindex;
+  int attribindex;
+#else /* not TRILIBRARY */
+  FILE *outfile;
+#endif /* not TRILIBRARY */
+  struct triedge triangleloop, trisym;
+  point torg, tdest, tapex;
+  REAL circumcenter[2];
+  REAL xi, eta;
+  int vnodenumber, vedgenumber;
+  int p1, p2;
+  int i;
+  triangle ptr;                         /* Temporary variable used by sym(). */
+
+#ifdef TRILIBRARY
+  if (!quiet) {
+    printf("Writing Voronoi vertices.\n");
+  }
+  /* Allocate memory for Voronoi vertices if necessary. */
+  if (*vpointlist == (REAL *) NULL) {
+    *vpointlist = (REAL *) malloc(triangles.items * 2 * sizeof(REAL));
+    if (*vpointlist == (REAL *) NULL) {
+      printf("Error:  Out of memory.\n");
+      exit(1);
+    }
+  }
+  /* Allocate memory for Voronoi vertex attributes if necessary. */
+  if (*vpointattriblist == (REAL *) NULL) {
+    *vpointattriblist = (REAL *) malloc(triangles.items * nextras *
+                                        sizeof(REAL));
+    if (*vpointattriblist == (REAL *) NULL) {
+      printf("Error:  Out of memory.\n");
+      exit(1);
+    }
+  }
+  *vpointmarkerlist = (int *) NULL;
+  plist = *vpointlist;
+  palist = *vpointattriblist;
+  coordindex = 0;
+  attribindex = 0;
+#else /* not TRILIBRARY */
+  if (!quiet) {
+    printf("Writing %s.\n", vnodefilename);
+  }
+  outfile = fopen(vnodefilename, "w");
+  if (outfile == (FILE *) NULL) {
+    printf("  Error:  Cannot create file %s.\n", vnodefilename);
+    exit(1);
+  }
+  /* Number of triangles, two dimensions, number of point attributes, */
+  /*   zero markers.                                                  */
+  fprintf(outfile, "%ld  %d  %d  %d\n", triangles.items, 2, nextras, 0);
+#endif /* not TRILIBRARY */
+
+  traversalinit(&triangles);
+  triangleloop.tri = triangletraverse();
+  triangleloop.orient = 0;
+  vnodenumber = firstnumber;
+  while (triangleloop.tri != (triangle *) NULL) {
+    org(triangleloop, torg);
+    dest(triangleloop, tdest);
+    apex(triangleloop, tapex);
+    findcircumcenter(torg, tdest, tapex, circumcenter, &xi, &eta);
+#ifdef TRILIBRARY
+    /* X and y coordinates. */
+    plist[coordindex++] = circumcenter[0];
+    plist[coordindex++] = circumcenter[1];
+    for (i = 2; i < 2 + nextras; i++) {
+      /* Interpolate the point attributes at the circumcenter. */
+      palist[attribindex++] = torg[i] + xi * (tdest[i] - torg[i])
+                                     + eta * (tapex[i] - torg[i]);
+    }
+#else /* not TRILIBRARY */
+    /* Voronoi vertex number, x and y coordinates. */
+    fprintf(outfile, "%4d    %.17g  %.17g", vnodenumber, circumcenter[0],
+            circumcenter[1]);
+    for (i = 2; i < 2 + nextras; i++) {
+      /* Interpolate the point attributes at the circumcenter. */
+      fprintf(outfile, "  %.17g", torg[i] + xi * (tdest[i] - torg[i])
+                                         + eta * (tapex[i] - torg[i]));
+    }
+    fprintf(outfile, "\n");
+#endif /* not TRILIBRARY */
+
+    * (int *) (triangleloop.tri + 6) = vnodenumber;
+    triangleloop.tri = triangletraverse();
+    vnodenumber++;
+  }
+
+#ifndef TRILIBRARY
+  finishfile(outfile, argc, argv);
+#endif /* not TRILIBRARY */
+
+#ifdef TRILIBRARY
+  if (!quiet) {
+    printf("Writing Voronoi edges.\n");
+  }
+  /* Allocate memory for output Voronoi edges if necessary. */
+  if (*vedgelist == (int *) NULL) {
+    *vedgelist = (int *) malloc(edges * 2 * sizeof(int));
+    if (*vedgelist == (int *) NULL) {
+      printf("Error:  Out of memory.\n");
+      exit(1);
+    }
+  }
+  *vedgemarkerlist = (int *) NULL;
+  /* Allocate memory for output Voronoi norms if necessary. */
+  if (*vnormlist == (REAL *) NULL) {
+    *vnormlist = (REAL *) malloc(edges * 2 * sizeof(REAL));
+    if (*vnormlist == (REAL *) NULL) {
+      printf("Error:  Out of memory.\n");
+      exit(1);
+    }
+  }
+  elist = *vedgelist;
+  normlist = *vnormlist;
+  coordindex = 0;
+#else /* not TRILIBRARY */
+  if (!quiet) {
+    printf("Writing %s.\n", vedgefilename);
+  }
+  outfile = fopen(vedgefilename, "w");
+  if (outfile == (FILE *) NULL) {
+    printf("  Error:  Cannot create file %s.\n", vedgefilename);
+    exit(1);
+  }
+  /* Number of edges, zero boundary markers. */
+  fprintf(outfile, "%ld  %d\n", edges, 0);
+#endif /* not TRILIBRARY */
+
+  traversalinit(&triangles);
+  triangleloop.tri = triangletraverse();
+  vedgenumber = firstnumber;
+  /* To loop over the set of edges, loop over all triangles, and look at   */
+  /*   the three edges of each triangle.  If there isn't another triangle  */
+  /*   adjacent to the edge, operate on the edge.  If there is another     */
+  /*   adjacent triangle, operate on the edge only if the current triangle */
+  /*   has a smaller pointer than its neighbor.  This way, each edge is    */
+  /*   considered only once.                                               */
+  while (triangleloop.tri != (triangle *) NULL) {
+    for (triangleloop.orient = 0; triangleloop.orient < 3;
+         triangleloop.orient++) {
+      sym(triangleloop, trisym);
+      if ((triangleloop.tri < trisym.tri) || (trisym.tri == dummytri)) {
+        /* Find the number of this triangle (and Voronoi vertex). */
+        p1 = * (int *) (triangleloop.tri + 6);
+        if (trisym.tri == dummytri) {
+          org(triangleloop, torg);
+          dest(triangleloop, tdest);
+#ifdef TRILIBRARY
+          /* Copy an infinite ray.  Index of one endpoint, and -1. */
+          elist[coordindex] = p1;
+          normlist[coordindex++] = tdest[1] - torg[1];
+          elist[coordindex] = -1;
+          normlist[coordindex++] = torg[0] - tdest[0];
+#else /* not TRILIBRARY */
+          /* Write an infinite ray.  Edge number, index of one endpoint, -1, */
+          /*   and x and y coordinates of a vector representing the          */
+          /*   direction of the ray.                                         */
+          fprintf(outfile, "%4d   %d  %d   %.17g  %.17g\n", vedgenumber,
+                  p1, -1, tdest[1] - torg[1], torg[0] - tdest[0]);
+#endif /* not TRILIBRARY */
+        } else {
+          /* Find the number of the adjacent triangle (and Voronoi vertex). */
+          p2 = * (int *) (trisym.tri + 6);
+          /* Finite edge.  Write indices of two endpoints. */
+#ifdef TRILIBRARY
+          elist[coordindex] = p1;
+          normlist[coordindex++] = 0.0;
+          elist[coordindex] = p2;
+          normlist[coordindex++] = 0.0;
+#else /* not TRILIBRARY */
+          fprintf(outfile, "%4d   %d  %d\n", vedgenumber, p1, p2);
+#endif /* not TRILIBRARY */
+        }
+        vedgenumber++;
+      }
+    }
+    triangleloop.tri = triangletraverse();
+  }
+
+#ifndef TRILIBRARY
+  finishfile(outfile, argc, argv);
+#endif /* not TRILIBRARY */
+}
+
+#ifdef TRILIBRARY
+
+void writeneighbors(neighborlist)
+int **neighborlist;
+
+#else /* not TRILIBRARY */
+
+void writeneighbors(neighborfilename, argc, argv)
+char *neighborfilename;
+int argc;
+char **argv;
+
+#endif /* not TRILIBRARY */
+
+{
+#ifdef TRILIBRARY
+  int *nlist;
+  int index;
+#else /* not TRILIBRARY */
+  FILE *outfile;
+#endif /* not TRILIBRARY */
+  struct triedge triangleloop, trisym;
+  int elementnumber;
+  int neighbor1, neighbor2, neighbor3;
+  triangle ptr;                         /* Temporary variable used by sym(). */
+
+#ifdef TRILIBRARY
+  if (!quiet) {
+    printf("Writing neighbors.\n");
+  }
+  /* Allocate memory for neighbors if necessary. */
+  if (*neighborlist == (int *) NULL) {
+    *neighborlist = (int *) malloc(triangles.items * 3 * sizeof(int));
+    if (*neighborlist == (int *) NULL) {
+      printf("Error:  Out of memory.\n");
+      exit(1);
+    }
+  }
+  nlist = *neighborlist;
+  index = 0;
+#else /* not TRILIBRARY */
+  if (!quiet) {
+    printf("Writing %s.\n", neighborfilename);
+  }
+  outfile = fopen(neighborfilename, "w");
+  if (outfile == (FILE *) NULL) {
+    printf("  Error:  Cannot create file %s.\n", neighborfilename);
+    exit(1);
+  }
+  /* Number of triangles, three edges per triangle. */
+  fprintf(outfile, "%ld  %d\n", triangles.items, 3);
+#endif /* not TRILIBRARY */
+
+  traversalinit(&triangles);
+  triangleloop.tri = triangletraverse();
+  triangleloop.orient = 0;
+  elementnumber = firstnumber;
+  while (triangleloop.tri != (triangle *) NULL) {
+    * (int *) (triangleloop.tri + 6) = elementnumber;
+    triangleloop.tri = triangletraverse();
+    elementnumber++;
+  }
+  * (int *) (dummytri + 6) = -1;
+
+  traversalinit(&triangles);
+  triangleloop.tri = triangletraverse();
+  elementnumber = firstnumber;
+  while (triangleloop.tri != (triangle *) NULL) {
+    triangleloop.orient = 1;
+    sym(triangleloop, trisym);
+    neighbor1 = * (int *) (trisym.tri + 6);
+    triangleloop.orient = 2;
+    sym(triangleloop, trisym);
+    neighbor2 = * (int *) (trisym.tri + 6);
+    triangleloop.orient = 0;
+    sym(triangleloop, trisym);
+    neighbor3 = * (int *) (trisym.tri + 6);
+#ifdef TRILIBRARY
+    nlist[index++] = neighbor1;
+    nlist[index++] = neighbor2;
+    nlist[index++] = neighbor3;
+#else /* not TRILIBRARY */
+    /* Triangle number, neighboring triangle numbers. */
+    fprintf(outfile, "%4d    %d  %d  %d\n", elementnumber,
+            neighbor1, neighbor2, neighbor3);
+#endif /* not TRILIBRARY */
+
+    triangleloop.tri = triangletraverse();
+    elementnumber++;
+  }
+
+#ifndef TRILIBRARY
+  finishfile(outfile, argc, argv);
+#endif /* TRILIBRARY */
+}
+
+/*****************************************************************************/
+/*                                                                           */
+/*  writeoff()   Write the triangulation to an .off file.                    */
+/*                                                                           */
+/*  OFF stands for the Object File Format, a format used by the Geometry     */
+/*  Center's Geomview package.                                               */
+/*                                                                           */
+/*****************************************************************************/
+
+#ifndef TRILIBRARY
+
+void writeoff(offfilename, argc, argv)
+char *offfilename;
+int argc;
+char **argv;
+{
+  FILE *outfile;
+  struct triedge triangleloop;
+  point pointloop;
+  point p1, p2, p3;
+
+  if (!quiet) {
+    printf("Writing %s.\n", offfilename);
+  }
+  outfile = fopen(offfilename, "w");
+  if (outfile == (FILE *) NULL) {
+    printf("  Error:  Cannot create file %s.\n", offfilename);
+    exit(1);
+  }
+  /* Number of points, triangles, and edges. */
+  fprintf(outfile, "OFF\n%ld  %ld  %ld\n", points.items, triangles.items,
+          edges);
+
+  /* Write the points. */
+  traversalinit(&points);
+  pointloop = pointtraverse();
+  while (pointloop != (point) NULL) {
+    /* The "0.0" is here because the OFF format uses 3D coordinates. */
+    fprintf(outfile, " %.17g  %.17g  %.17g\n", pointloop[0],
+            pointloop[1], 0.0);
+    pointloop = pointtraverse();
+  }
+
+  /* Write the triangles. */
+  traversalinit(&triangles);
+  triangleloop.tri = triangletraverse();
+  triangleloop.orient = 0;
+  while (triangleloop.tri != (triangle *) NULL) {
+    org(triangleloop, p1);
+    dest(triangleloop, p2);
+    apex(triangleloop, p3);
+    /* The "3" means a three-vertex polygon. */
+    fprintf(outfile, " 3   %4d  %4d  %4d\n", pointmark(p1) - 1,
+            pointmark(p2) - 1, pointmark(p3) - 1);
+    triangleloop.tri = triangletraverse();
+  }
+  finishfile(outfile, argc, argv);
+}
+
+#endif /* not TRILIBRARY */
+
+/**                                                                         **/
+/**                                                                         **/
+/********* File I/O routines end here                                *********/
+
+/*****************************************************************************/
+/*                                                                           */
+/*  quality_statistics()   Print statistics about the quality of the mesh.   */
+/*                                                                           */
+/*****************************************************************************/
+
+void quality_statistics()
+{
+  struct triedge triangleloop;
+  point p[3];
+  REAL cossquaretable[8];
+  REAL ratiotable[16];
+  REAL dx[3], dy[3];
+  REAL edgelength[3];
+  REAL dotproduct;
+  REAL cossquare;
+  REAL triarea;
+  REAL shortest, longest;
+  REAL trilongest2;
+  REAL smallestarea, biggestarea;
+  REAL triminaltitude2;
+  REAL minaltitude;
+  REAL triaspect2;
+  REAL worstaspect;
+  REAL smallestangle, biggestangle;
+  REAL radconst, degconst;
+  int angletable[18];
+  int aspecttable[16];
+  int aspectindex;
+  int tendegree;
+  int acutebiggest;
+  int i, ii, j, k;
+
+  printf("Mesh quality statistics:\n\n");
+  radconst = PI / 18.0;
+  degconst = 180.0 / PI;
+  for (i = 0; i < 8; i++) {
+    cossquaretable[i] = cos(radconst * (REAL) (i + 1));
+    cossquaretable[i] = cossquaretable[i] * cossquaretable[i];
+  }
+  for (i = 0; i < 18; i++) {
+    angletable[i] = 0;
+  }
+
+  ratiotable[0]  =      1.5;      ratiotable[1]  =     2.0;
+  ratiotable[2]  =      2.5;      ratiotable[3]  =     3.0;
+  ratiotable[4]  =      4.0;      ratiotable[5]  =     6.0;
+  ratiotable[6]  =     10.0;      ratiotable[7]  =    15.0;
+  ratiotable[8]  =     25.0;      ratiotable[9]  =    50.0;
+  ratiotable[10] =    100.0;      ratiotable[11] =   300.0;
+  ratiotable[12] =   1000.0;      ratiotable[13] = 10000.0;
+  ratiotable[14] = 100000.0;      ratiotable[15] =     0.0;
+  for (i = 0; i < 16; i++) {
+    aspecttable[i] = 0;
+  }
+
+  worstaspect = 0.0;
+  minaltitude = xmax - xmin + ymax - ymin;
+  minaltitude = minaltitude * minaltitude;
+  shortest = minaltitude;
+  longest = 0.0;
+  smallestarea = minaltitude;
+  biggestarea = 0.0;
+  worstaspect = 0.0;
+  smallestangle = 0.0;
+  biggestangle = 2.0;
+  acutebiggest = 1;
+
+  traversalinit(&triangles);
+  triangleloop.tri = triangletraverse();
+  triangleloop.orient = 0;
+  while (triangleloop.tri != (triangle *) NULL) {
+    org(triangleloop, p[0]);
+    dest(triangleloop, p[1]);
+    apex(triangleloop, p[2]);
+    trilongest2 = 0.0;
+
+    for (i = 0; i < 3; i++) {
+      j = plus1mod3[i];
+      k = minus1mod3[i];
+      dx[i] = p[j][0] - p[k][0];
+      dy[i] = p[j][1] - p[k][1];
+      edgelength[i] = dx[i] * dx[i] + dy[i] * dy[i];
+      if (edgelength[i] > trilongest2) {
+        trilongest2 = edgelength[i];
+      }
+      if (edgelength[i] > longest) {
+        longest = edgelength[i];
+      }
+      if (edgelength[i] < shortest) {
+        shortest = edgelength[i];
+      }
+    }
+
+    triarea = counterclockwise(p[0], p[1], p[2]);
+    if (triarea < smallestarea) {
+      smallestarea = triarea;
+    }
+    if (triarea > biggestarea) {
+      biggestarea = triarea;
+    }
+    triminaltitude2 = triarea * triarea / trilongest2;
+    if (triminaltitude2 < minaltitude) {
+      minaltitude = triminaltitude2;
+    }
+    triaspect2 = trilongest2 / triminaltitude2;
+    if (triaspect2 > worstaspect) {
+      worstaspect = triaspect2;
+    }
+    aspectindex = 0;
+    while ((triaspect2 > ratiotable[aspectindex] * ratiotable[aspectindex])
+           && (aspectindex < 15)) {
+      aspectindex++;
+    }
+    aspecttable[aspectindex]++;
+
+    for (i = 0; i < 3; i++) {
+      j = plus1mod3[i];
+      k = minus1mod3[i];
+      dotproduct = dx[j] * dx[k] + dy[j] * dy[k];
+      cossquare = dotproduct * dotproduct / (edgelength[j] * edgelength[k]);
+      tendegree = 8;
+      for (ii = 7; ii >= 0; ii--) {
+        if (cossquare > cossquaretable[ii]) {
+          tendegree = ii;
+        }
+      }
+      if (dotproduct <= 0.0) {
+        angletable[tendegree]++;
+        if (cossquare > smallestangle) {
+          smallestangle = cossquare;
+        }
+        if (acutebiggest && (cossquare < biggestangle)) {
+          biggestangle = cossquare;
+        }
+      } else {
+        angletable[17 - tendegree]++;
+        if (acutebiggest || (cossquare > biggestangle)) {
+          biggestangle = cossquare;
+          acutebiggest = 0;
+        }
+      }
+    }
+    triangleloop.tri = triangletraverse();
+  }
+
+  shortest = sqrt(shortest);
+  longest = sqrt(longest);
+  minaltitude = sqrt(minaltitude);
+  worstaspect = sqrt(worstaspect);
+  smallestarea *= 2.0;
+  biggestarea *= 2.0;
+  if (smallestangle >= 1.0) {
+    smallestangle = 0.0;
+  } else {
+    smallestangle = degconst * acos(sqrt(smallestangle));
+  }
+  if (biggestangle >= 1.0) {
+    biggestangle = 180.0;
+  } else {
+    if (acutebiggest) {
+      biggestangle = degconst * acos(sqrt(biggestangle));
+    } else {
+      biggestangle = 180.0 - degconst * acos(sqrt(biggestangle));
+    }
+  }
+
+  printf("  Smallest area: %16.5g   |  Largest area: %16.5g\n",
+         smallestarea, biggestarea);
+  printf("  Shortest edge: %16.5g   |  Longest edge: %16.5g\n",
+         shortest, longest);
+  printf("  Shortest altitude: %12.5g   |  Largest aspect ratio: %8.5g\n\n",
+         minaltitude, worstaspect);
+  printf("  Aspect ratio histogram:\n");
+  printf("  1.1547 - %-6.6g    :  %8d    | %6.6g - %-6.6g     :  %8d\n",
+         ratiotable[0], aspecttable[0], ratiotable[7], ratiotable[8],
+         aspecttable[8]);
+  for (i = 1; i < 7; i++) {
+    printf("  %6.6g - %-6.6g    :  %8d    | %6.6g - %-6.6g     :  %8d\n",
+           ratiotable[i - 1], ratiotable[i], aspecttable[i],
+           ratiotable[i + 7], ratiotable[i + 8], aspecttable[i + 8]);
+  }
+  printf("  %6.6g - %-6.6g    :  %8d    | %6.6g -            :  %8d\n",
+         ratiotable[6], ratiotable[7], aspecttable[7], ratiotable[14],
+         aspecttable[15]);
+  printf(
+"  (Triangle aspect ratio is longest edge divided by shortest altitude)\n\n");
+  printf("  Smallest angle: %15.5g   |  Largest angle: %15.5g\n\n",
+         smallestangle, biggestangle);
+  printf("  Angle histogram:\n");
+  for (i = 0; i < 9; i++) {
+    printf("    %3d - %3d degrees:  %8d    |    %3d - %3d degrees:  %8d\n",
+           i * 10, i * 10 + 10, angletable[i],
+           i * 10 + 90, i * 10 + 100, angletable[i + 9]);
+  }
+  printf("\n");
+}
+
+/*****************************************************************************/
+/*                                                                           */
+/*  statistics()   Print all sorts of cool facts.                            */
+/*                                                                           */
+/*****************************************************************************/
+
+void statistics()
+{
+  printf("\nStatistics:\n\n");
+  printf("  Input points: %d\n", inpoints);
+  if (refine) {
+    printf("  Input triangles: %d\n", inelements);
+  }
+  if (poly) {
+    printf("  Input segments: %d\n", insegments);
+    if (!refine) {
+      printf("  Input holes: %d\n", holes);
+    }
+  }
+
+  printf("\n  Mesh points: %ld\n", points.items);
+  printf("  Mesh triangles: %ld\n", triangles.items);
+  printf("  Mesh edges: %ld\n", edges);
+  if (poly || refine) {
+    printf("  Mesh boundary edges: %ld\n", hullsize);
+    printf("  Mesh segments: %ld\n\n", shelles.items);
+  } else {
+    printf("  Mesh convex hull edges: %ld\n\n", hullsize);
+  }
+  if (verbose) {
+    quality_statistics();
+    printf("Memory allocation statistics:\n\n");
+    printf("  Maximum number of points: %ld\n", points.maxitems);
+    printf("  Maximum number of triangles: %ld\n", triangles.maxitems);
+    if (shelles.maxitems > 0) {
+      printf("  Maximum number of segments: %ld\n", shelles.maxitems);
+    }
+    if (viri.maxitems > 0) {
+      printf("  Maximum number of viri: %ld\n", viri.maxitems);
+    }
+    if (badsegments.maxitems > 0) {
+      printf("  Maximum number of encroached segments: %ld\n",
+             badsegments.maxitems);
+    }
+    if (badtriangles.maxitems > 0) {
+      printf("  Maximum number of bad triangles: %ld\n",
+             badtriangles.maxitems);
+    }
+    if (splaynodes.maxitems > 0) {
+      printf("  Maximum number of splay tree nodes: %ld\n",
+             splaynodes.maxitems);
+    }
+    printf("  Approximate heap memory use (bytes): %ld\n\n",
+           points.maxitems * points.itembytes
+           + triangles.maxitems * triangles.itembytes
+           + shelles.maxitems * shelles.itembytes
+           + viri.maxitems * viri.itembytes
+           + badsegments.maxitems * badsegments.itembytes
+           + badtriangles.maxitems * badtriangles.itembytes
+           + splaynodes.maxitems * splaynodes.itembytes);
+
+    printf("Algorithmic statistics:\n\n");
+    printf("  Number of incircle tests: %ld\n", incirclecount);
+    printf("  Number of orientation tests: %ld\n", counterclockcount);
+    if (hyperbolacount > 0) {
+      printf("  Number of right-of-hyperbola tests: %ld\n",
+             hyperbolacount);
+    }
+    if (circumcentercount > 0) {
+      printf("  Number of circumcenter computations: %ld\n",
+             circumcentercount);
+    }
+    if (circletopcount > 0) {
+      printf("  Number of circle top computations: %ld\n",
+             circletopcount);
+    }
+    printf("\n");
+  }
+}
+
+/*****************************************************************************/
+/*                                                                           */
+/*  main() or triangulate()   Gosh, do everything.                           */
+/*                                                                           */
+/*  The sequence is roughly as follows.  Many of these steps can be skipped, */
+/*  depending on the command line switches.                                  */
+/*                                                                           */
+/*  - Initialize constants and parse the command line.                       */
+/*  - Read the points from a file and either                                 */
+/*    - triangulate them (no -r), or                                         */
+/*    - read an old mesh from files and reconstruct it (-r).                 */
+/*  - Insert the PSLG segments (-p), and possibly segments on the convex     */
+/*      hull (-c).                                                           */
+/*  - Read the holes (-p), regional attributes (-pA), and regional area      */
+/*      constraints (-pa).  Carve the holes and concavities, and spread the  */
+/*      regional attributes and area constraints.                            */
+/*  - Enforce the constraints on minimum angle (-q) and maximum area (-a).   */
+/*      Also enforce the conforming Delaunay property (-q and -a).           */
+/*  - Compute the number of edges in the resulting mesh.                     */
+/*  - Promote the mesh's linear triangles to higher order elements (-o).     */
+/*  - Write the output files and print the statistics.                       */
+/*  - Check the consistency and Delaunay property of the mesh (-C).          */
+/*                                                                           */
+/*****************************************************************************/
+
+#ifdef TRILIBRARY
+
+void triangulate(triswitches, in, out, vorout)
+char *triswitches;
+struct triangulateio *in;
+struct triangulateio *out;
+struct triangulateio *vorout;
+
+#else /* not TRILIBRARY */
+
+int main(argc, argv)
+int argc;
+char **argv;
+
+#endif /* not TRILIBRARY */
+
+{
+  REAL *holearray;                                        /* Array of holes. */
+  REAL *regionarray;   /* Array of regional attributes and area constraints. */
+#ifndef TRILIBRARY
+  FILE *polyfile;
+#endif /* not TRILIBRARY */
+#ifndef NO_TIMER
+  /* Variables for timing the performance of Triangle.  The types are */
+  /*   defined in sys/time.h.                                         */
+  struct timeval tv0, tv1, tv2, tv3, tv4, tv5, tv6;
+  struct timezone tz;
+#endif /* NO_TIMER */
+
+#ifndef NO_TIMER
+  gettimeofday(&tv0, &tz);
+#endif /* NO_TIMER */
+
+  triangleinit();
+#ifdef TRILIBRARY
+  parsecommandline(1, &triswitches);
+#else /* not TRILIBRARY */
+  parsecommandline(argc, argv);
+#endif /* not TRILIBRARY */
+
+#ifdef TRILIBRARY
+  transfernodes(in->pointlist, in->pointattributelist, in->pointmarkerlist,
+                in->numberofpoints, in->numberofpointattributes);
+#else /* not TRILIBRARY */
+  readnodes(innodefilename, inpolyfilename, &polyfile);
+#endif /* not TRILIBRARY */
+
+#ifndef NO_TIMER
+  if (!quiet) {
+    gettimeofday(&tv1, &tz);
+  }
+#endif /* NO_TIMER */
+
+#ifdef CDT_ONLY
+  hullsize = delaunay();                          /* Triangulate the points. */
+#else /* not CDT_ONLY */
+  if (refine) {
+    /* Read and reconstruct a mesh. */
+#ifdef TRILIBRARY
+    hullsize = reconstruct(in->trianglelist, in->triangleattributelist,
+                           in->trianglearealist, in->numberoftriangles,
+                           in->numberofcorners, in->numberoftriangleattributes,
+                           in->segmentlist, in->segmentmarkerlist,
+                           in->numberofsegments);
+#else /* not TRILIBRARY */
+    hullsize = reconstruct(inelefilename, areafilename, inpolyfilename,
+                           polyfile);
+#endif /* not TRILIBRARY */
+  } else {
+    hullsize = delaunay();                        /* Triangulate the points. */
+  }
+#endif /* not CDT_ONLY */
+
+#ifndef NO_TIMER
+  if (!quiet) {
+    gettimeofday(&tv2, &tz);
+    if (refine) {
+      printf("Mesh reconstruction");
+    } else {
+      printf("Delaunay");
+    }
+    printf(" milliseconds:  %ld\n", 1000l * (tv2.tv_sec - tv1.tv_sec)
+           + (tv2.tv_usec - tv1.tv_usec) / 1000l);
+  }
+#endif /* NO_TIMER */
+
+  /* Ensure that no point can be mistaken for a triangular bounding */
+  /*   box point in insertsite().                                   */
+  infpoint1 = (point) NULL;
+  infpoint2 = (point) NULL;
+  infpoint3 = (point) NULL;
+
+  if (useshelles) {
+    checksegments = 1;                  /* Segments will be introduced next. */
+    if (!refine) {
+      /* Insert PSLG segments and/or convex hull segments. */
+#ifdef TRILIBRARY
+      insegments = formskeleton(in->segmentlist, in->segmentmarkerlist,
+                                in->numberofsegments);
+#else /* not TRILIBRARY */
+      insegments = formskeleton(polyfile, inpolyfilename);
+#endif /* not TRILIBRARY */
+    }
+  }
+
+#ifndef NO_TIMER
+  if (!quiet) {
+    gettimeofday(&tv3, &tz);
+    if (useshelles && !refine) {
+      printf("Segment milliseconds:  %ld\n",
+             1000l * (tv3.tv_sec - tv2.tv_sec)
+             + (tv3.tv_usec - tv2.tv_usec) / 1000l);
+    }
+  }
+#endif /* NO_TIMER */
+
+  if (poly) {
+#ifdef TRILIBRARY
+    holearray = in->holelist;
+    holes = in->numberofholes;
+    regionarray = in->regionlist;
+    regions = in->numberofregions;
+#else /* not TRILIBRARY */
+    readholes(polyfile, inpolyfilename, &holearray, &holes,
+              &regionarray, &regions);
+#endif /* not TRILIBRARY */
+    if (!refine) {
+      /* Carve out holes and concavities. */
+      carveholes(holearray, holes, regionarray, regions);
+    }
+  } else {
+    /* Without a PSLG, there can be no holes or regional attributes   */
+    /*   or area constraints.  The following are set to zero to avoid */
+    /*   an accidental free() later.                                  */
+    holes = 0;
+    regions = 0;
+  }
+
+#ifndef NO_TIMER
+  if (!quiet) {
+    gettimeofday(&tv4, &tz);
+    if (poly && !refine) {
+      printf("Hole milliseconds:  %ld\n", 1000l * (tv4.tv_sec - tv3.tv_sec)
+             + (tv4.tv_usec - tv3.tv_usec) / 1000l);
+    }
+  }
+#endif /* NO_TIMER */
+
+#ifndef CDT_ONLY
+  if (quality) {
+    enforcequality();                 /* Enforce angle and area constraints. */
+  }
+#endif /* not CDT_ONLY */
+
+#ifndef NO_TIMER
+  if (!quiet) {
+    gettimeofday(&tv5, &tz);
+#ifndef CDT_ONLY
+    if (quality) {
+      printf("Quality milliseconds:  %ld\n",
+             1000l * (tv5.tv_sec - tv4.tv_sec)
+             + (tv5.tv_usec - tv4.tv_usec) / 1000l);
+    }
+#endif /* not CDT_ONLY */
+  }
+#endif /* NO_TIMER */
+
+  /* Compute the number of edges. */
+  edges = (3l * triangles.items + hullsize) / 2l;
+
+  if (order > 1) {
+    highorder();             /* Promote elements to higher polynomial order. */
+  }
+  if (!quiet) {
+    printf("\n");
+  }
+
+#ifdef TRILIBRARY
+  out->numberofpoints = points.items;
+  out->numberofpointattributes = nextras;
+  out->numberoftriangles = triangles.items;
+  out->numberofcorners = (order + 1) * (order + 2) / 2;
+  out->numberoftriangleattributes = eextras;
+  out->numberofedges = edges;
+  if (useshelles) {
+    out->numberofsegments = shelles.items;
+  } else {
+    out->numberofsegments = hullsize;
+  }
+  if (vorout != (struct triangulateio *) NULL) {
+    vorout->numberofpoints = triangles.items;
+    vorout->numberofpointattributes = nextras;
+    vorout->numberofedges = edges;
+  }
+#endif /* TRILIBRARY */
+  /* If not using iteration numbers, don't write a .node file if one was */
+  /*   read, because the original one would be overwritten!              */
+  if (nonodewritten || (noiterationnum && readnodefile)) {
+    if (!quiet) {
+#ifdef TRILIBRARY
+      printf("NOT writing points.\n");
+#else /* not TRILIBRARY */
+      printf("NOT writing a .node file.\n");
+#endif /* not TRILIBRARY */
+    }
+    numbernodes();                 /* We must remember to number the points. */
+  } else {
+#ifdef TRILIBRARY
+    writenodes(&out->pointlist, &out->pointattributelist,
+               &out->pointmarkerlist);
+#else /* not TRILIBRARY */
+    writenodes(outnodefilename, argc, argv);      /* Numbers the points too. */
+#endif /* TRILIBRARY */
+  }
+  if (noelewritten) {
+    if (!quiet) {
+#ifdef TRILIBRARY
+      printf("NOT writing triangles.\n");
+#else /* not TRILIBRARY */
+      printf("NOT writing an .ele file.\n");
+#endif /* not TRILIBRARY */
+    }
+  } else {
+#ifdef TRILIBRARY
+    writeelements(&out->trianglelist, &out->triangleattributelist);
+#else /* not TRILIBRARY */
+    writeelements(outelefilename, argc, argv);
+#endif /* not TRILIBRARY */
+  }
+  /* The -c switch (convex switch) causes a PSLG to be written */
+  /*   even if none was read.                                  */
+  if (poly || convex) {
+    /* If not using iteration numbers, don't overwrite the .poly file. */
+    if (nopolywritten || noiterationnum) {
+      if (!quiet) {
+#ifdef TRILIBRARY
+        printf("NOT writing segments.\n");
+#else /* not TRILIBRARY */
+        printf("NOT writing a .poly file.\n");
+#endif /* not TRILIBRARY */
+      }
+    } else {
+#ifdef TRILIBRARY
+      writepoly(&out->segmentlist, &out->segmentmarkerlist);
+      out->numberofholes = holes;
+      out->numberofregions = regions;
+      if (poly) {
+        out->holelist = in->holelist;
+        out->regionlist = in->regionlist;
+      } else {
+        out->holelist = (REAL *) NULL;
+        out->regionlist = (REAL *) NULL;
+      }
+#else /* not TRILIBRARY */
+      writepoly(outpolyfilename, holearray, holes, regionarray, regions,
+                argc, argv);
+#endif /* not TRILIBRARY */
+    }
+  }
+#ifndef TRILIBRARY
+#ifndef CDT_ONLY
+  if (regions > 0) {
+    free(regionarray);
+  }
+#endif /* not CDT_ONLY */
+  if (holes > 0) {
+    free(holearray);
+  }
+  if (geomview) {
+    writeoff(offfilename, argc, argv);
+  }
+#endif /* not TRILIBRARY */
+  if (edgesout) {
+#ifdef TRILIBRARY
+    writeedges(&out->edgelist, &out->edgemarkerlist);
+#else /* not TRILIBRARY */
+    writeedges(edgefilename, argc, argv);
+#endif /* not TRILIBRARY */
+  }
+  if (voronoi) {
+#ifdef TRILIBRARY
+    writevoronoi(&vorout->pointlist, &vorout->pointattributelist,
+                 &vorout->pointmarkerlist, &vorout->edgelist,
+                 &vorout->edgemarkerlist, &vorout->normlist);
+#else /* not TRILIBRARY */
+    writevoronoi(vnodefilename, vedgefilename, argc, argv);
+#endif /* not TRILIBRARY */
+  }
+  if (neighbors) {
+#ifdef TRILIBRARY
+    writeneighbors(&out->neighborlist);
+#else /* not TRILIBRARY */
+    writeneighbors(neighborfilename, argc, argv);
+#endif /* not TRILIBRARY */
+  }
+
+  if (!quiet) {
+#ifndef NO_TIMER
+    gettimeofday(&tv6, &tz);
+    printf("\nOutput milliseconds:  %ld\n",
+           1000l * (tv6.tv_sec - tv5.tv_sec)
+           + (tv6.tv_usec - tv5.tv_usec) / 1000l);
+    printf("Total running milliseconds:  %ld\n",
+           1000l * (tv6.tv_sec - tv0.tv_sec)
+           + (tv6.tv_usec - tv0.tv_usec) / 1000l);
+#endif /* NO_TIMER */
+
+    statistics();
+  }
+
+#ifndef REDUCED
+  if (docheck) {
+    checkmesh();
+    checkdelaunay();
+  }
+#endif /* not REDUCED */
+
+  triangledeinit();
+#ifndef TRILIBRARY
+  return 0;
+#endif /* not TRILIBRARY */
+}

diff --git a/Triangle/triangle.h b/Triangle/triangle.h
new file mode 100644 (file)
index 0000000..8fb5430
--- /dev/null
+++ b/Triangle/triangle.h
@@ -0,0 +1,284 @@
+/*****************************************************************************/
+/*                                                                           */
+/*  (triangle.h)                                                             */
+/*                                                                           */
+/*  Include file for programs that call Triangle.                            */
+/*                                                                           */
+/*  Accompanies Triangle Version 1.3                                         */
+/*  July 19, 1996                                                            */
+/*                                                                           */
+/*  Copyright 1996                                                           */
+/*  Jonathan Richard Shewchuk                                                */
+/*  School of Computer Science                                               */
+/*  Carnegie Mellon University                                               */
+/*  5000 Forbes Avenue                                                       */
+/*  Pittsburgh, Pennsylvania  15213-3891                                     */
+/*  jrs@cs.cmu.edu                                                           */
+/*                                                                           */
+/*****************************************************************************/
+
+/*****************************************************************************/
+/*                                                                           */
+/*  How to call Triangle from another program                                */
+/*                                                                           */
+/*                                                                           */
+/*  If you haven't read Triangle's instructions (run "triangle -h" to read   */
+/*  them), you won't understand what follows.                                */
+/*                                                                           */
+/*  Triangle must be compiled into an object file (triangle.o) with the      */
+/*  TRILIBRARY symbol defined (preferably by using the -DTRILIBRARY compiler */
+/*  switch).  The makefile included with Triangle will do this for you if    */
+/*  you run "make trilibrary".  The resulting object file can be called via  */
+/*  the procedure triangulate().                                             */
+/*                                                                           */
+/*  If the size of the object file is important to you, you may wish to      */
+/*  generate a reduced version of triangle.o.  The REDUCED symbol gets rid   */
+/*  of all features that are primarily of research interest.  Specifically,  */
+/*  the -DREDUCED switch eliminates Triangle's -i, -F, -s, and -C switches.  */
+/*  The CDT_ONLY symbol gets rid of all meshing algorithms above and beyond  */
+/*  constrained Delaunay triangulation.  Specifically, the -DCDT_ONLY switch */
+/*  eliminates Triangle's -r, -q, -a, -S, and -s switches.                   */
+/*                                                                           */
+/*  IMPORTANT:  These definitions (TRILIBRARY, REDUCED, CDT_ONLY) must be    */
+/*  made in the makefile or in triangle.c itself.  Putting these definitions */
+/*  in this file will not create the desired effect.                         */
+/*                                                                           */
+/*                                                                           */
+/*  The calling convention for triangulate() follows.                        */
+/*                                                                           */
+/*      void triangulate(triswitches, in, out, vorout)                       */
+/*      char *triswitches;                                                   */
+/*      struct triangulateio *in;                                            */
+/*      struct triangulateio *out;                                           */
+/*      struct triangulateio *vorout;                                        */
+/*                                                                           */
+/*  `triswitches' is a string containing the command line switches you wish  */
+/*  to invoke.  No initial dash is required.  Some suggestions:              */
+/*                                                                           */
+/*  - You'll probably find it convenient to use the `z' switch so that       */
+/*    points (and other items) are numbered from zero.  This simplifies      */
+/*    indexing, because the first item of any type always starts at index    */
+/*    [0] of the corresponding array, whether that item's number is zero or  */
+/*    one.                                                                   */
+/*  - You'll probably want to use the `Q' (quiet) switch in your final code, */
+/*    but you can take advantage of Triangle's printed output (including the */
+/*    `V' switch) while debugging.                                           */
+/*  - If you are not using the `q' or `a' switches, then the output points   */
+/*    will be identical to the input points, except possibly for the         */
+/*    boundary markers.  If you don't need the boundary markers, you should  */
+/*    use the `N' (no nodes output) switch to save memory.  (If you do need  */
+/*    boundary markers, but need to save memory, a good nasty trick is to    */
+/*    set out->pointlist equal to in->pointlist before calling triangulate(),*/
+/*    so that Triangle overwrites the input points with identical copies.)   */
+/*  - The `I' (no iteration numbers) and `g' (.off file output) switches     */
+/*    have no effect when Triangle is compiled with TRILIBRARY defined.      */
+/*                                                                           */
+/*  `in', `out', and `vorout' are descriptions of the input, the output,     */
+/*  and the Voronoi output.  If the `v' (Voronoi output) switch is not used, */
+/*  `vorout' may be NULL.  `in' and `out' may never be NULL.                 */
+/*                                                                           */
+/*  Certain fields of the input and output structures must be initialized,   */
+/*  as described below.                                                      */
+/*                                                                           */
+/*****************************************************************************/
+
+/*****************************************************************************/
+/*                                                                           */
+/*  The `triangulateio' structure.                                           */
+/*                                                                           */
+/*  Used to pass data into and out of the triangulate() procedure.           */
+/*                                                                           */
+/*                                                                           */
+/*  Arrays are used to store points, triangles, markers, and so forth.  In   */
+/*  all cases, the first item in any array is stored starting at index [0].  */
+/*  However, that item is item number `1' unless the `z' switch is used, in  */
+/*  which case it is item number `0'.  Hence, you may find it easier to      */
+/*  index points (and triangles in the neighbor list) if you use the `z'     */
+/*  switch.  Unless, of course, you're calling Triangle from a Fortran       */
+/*  program.                                                                 */
+/*                                                                           */
+/*  Description of fields (except the `numberof' fields, which are obvious): */
+/*                                                                           */
+/*  `pointlist':  An array of point coordinates.  The first point's x        */
+/*    coordinate is at index [0] and its y coordinate at index [1], followed */
+/*    by the coordinates of the remaining points.  Each point occupies two   */
+/*    REALs.                                                                 */
+/*  `pointattributelist':  An array of point attributes.  Each point's       */
+/*    attributes occupy `numberofpointattributes' REALs.                     */
+/*  `pointmarkerlist':  An array of point markers; one int per point.        */
+/*                                                                           */
+/*  `trianglelist':  An array of triangle corners.  The first triangle's     */
+/*    first corner is at index [0], followed by its other two corners in     */
+/*    counterclockwise order, followed by any other nodes if the triangle    */
+/*    represents a nonlinear element.  Each triangle occupies                */
+/*    `numberofcorners' ints.                                                */
+/*  `triangleattributelist':  An array of triangle attributes.  Each         */
+/*    triangle's attributes occupy `numberoftriangleattributes' REALs.       */
+/*  `trianglearealist':  An array of triangle area constraints; one REAL per */
+/*    triangle.  Input only.                                                 */
+/*  `neighborlist':  An array of triangle neighbors; three ints per          */
+/*    triangle.  Output only.                                                */
+/*                                                                           */
+/*  `segmentlist':  An array of segment endpoints.  The first segment's      */
+/*    endpoints are at indices [0] and [1], followed by the remaining        */
+/*    segments.  Two ints per segment.                                       */
+/*  `segmentmarkerlist':  An array of segment markers; one int per segment.  */
+/*                                                                           */
+/*  `holelist':  An array of holes.  The first hole's x and y coordinates    */
+/*    are at indices [0] and [1], followed by the remaining holes.  Two      */
+/*    REALs per hole.  Input only, although the pointer is copied to the     */
+/*    output structure for your convenience.                                 */
+/*                                                                           */
+/*  `regionlist':  An array of regional attributes and area constraints.     */
+/*    The first constraint's x and y coordinates are at indices [0] and [1], */
+/*    followed by the regional attribute and index [2], followed by the      */
+/*    maximum area at index [3], followed by the remaining area constraints. */
+/*    Four REALs per area constraint.  Note that each regional attribute is  */
+/*    used only if you select the `A' switch, and each area constraint is    */
+/*    used only if you select the `a' switch (with no number following), but */
+/*    omitting one of these switches does not change the memory layout.      */
+/*    Input only, although the pointer is copied to the output structure for */
+/*    your convenience.                                                      */
+/*                                                                           */
+/*  `edgelist':  An array of edge endpoints.  The first edge's endpoints are */
+/*    at indices [0] and [1], followed by the remaining edges.  Two ints per */
+/*    edge.  Output only.                                                    */
+/*  `edgemarkerlist':  An array of edge markers; one int per edge.  Output   */
+/*    only.                                                                  */
+/*  `normlist':  An array of normal vectors, used for infinite rays in       */
+/*    Voronoi diagrams.  The first normal vector's x and y magnitudes are    */
+/*    at indices [0] and [1], followed by the remaining vectors.  For each   */
+/*    finite edge in a Voronoi diagram, the normal vector written is the     */
+/*    zero vector.  Two REALs per edge.  Output only.                        */
+/*                                                                           */
+/*                                                                           */
+/*  Any input fields that Triangle will examine must be initialized.         */
+/*  Furthermore, for each output array that Triangle will write to, you      */
+/*  must either provide space by setting the appropriate pointer to point    */
+/*  to the space you want the data written to, or you must initialize the    */
+/*  pointer to NULL, which tells Triangle to allocate space for the results. */
+/*  The latter option is preferable, because Triangle always knows exactly   */
+/*  how much space to allocate.  The former option is provided mainly for    */
+/*  people who need to call Triangle from Fortran code, though it also makes */
+/*  possible some nasty space-saving tricks, like writing the output to the  */
+/*  same arrays as the input.                                                */
+/*                                                                           */
+/*  Triangle will not free() any input or output arrays, including those it  */
+/*  allocates itself; that's up to you.                                      */
+/*                                                                           */
+/*  Here's a guide to help you decide which fields you must initialize       */
+/*  before you call triangulate().                                           */
+/*                                                                           */
+/*  `in':                                                                    */
+/*                                                                           */
+/*    - `pointlist' must always point to a list of points; `numberofpoints'  */
+/*      and `numberofpointattributes' must be properly set.                  */
+/*      `pointmarkerlist' must either be set to NULL (in which case all      */
+/*      markers default to zero), or must point to a list of markers.  If    */
+/*      `numberofpointattributes' is not zero, `pointattributelist' must     */
+/*      point to a list of point attributes.                                 */
+/*    - If the `r' switch is used, `trianglelist' must point to a list of    */
+/*      triangles, and `numberoftriangles', `numberofcorners', and           */
+/*      `numberoftriangleattributes' must be properly set.  If               */
+/*      `numberoftriangleattributes' is not zero, `triangleattributelist'    */
+/*      must point to a list of triangle attributes.  If the `a' switch is   */
+/*      used (with no number following), `trianglearealist' must point to a  */
+/*      list of triangle area constraints.  `neighborlist' may be ignored.   */
+/*    - If the `p' switch is used, `segmentlist' must point to a list of     */
+/*      segments, `numberofsegments' must be properly set, and               */
+/*      `segmentmarkerlist' must either be set to NULL (in which case all    */
+/*      markers default to zero), or must point to a list of markers.        */
+/*    - If the `p' switch is used without the `r' switch, then               */
+/*      `numberofholes' and `numberofregions' must be properly set.  If      */
+/*      `numberofholes' is not zero, `holelist' must point to a list of      */
+/*      holes.  If `numberofregions' is not zero, `regionlist' must point to */
+/*      a list of region constraints.                                        */
+/*    - If the `p' switch is used, `holelist', `numberofholes',              */
+/*      `regionlist', and `numberofregions' is copied to `out'.  (You can    */
+/*      nonetheless get away with not initializing them if the `r' switch is */
+/*      used.)                                                               */
+/*    - `edgelist', `edgemarkerlist', `normlist', and `numberofedges' may be */
+/*      ignored.                                                             */
+/*                                                                           */
+/*  `out':                                                                   */
+/*                                                                           */
+/*    - `pointlist' must be initialized (NULL or pointing to memory) unless  */
+/*      the `N' switch is used.  `pointmarkerlist' must be initialized       */
+/*      unless the `N' or `B' switch is used.  If `N' is not used and        */
+/*      `in->numberofpointattributes' is not zero, `pointattributelist' must */
+/*      be initialized.                                                      */
+/*    - `trianglelist' must be initialized unless the `E' switch is used.    */
+/*      `neighborlist' must be initialized if the `n' switch is used.  If    */
+/*      the `E' switch is not used and (`in->numberofelementattributes' is   */
+/*      not zero or the `A' switch is used), `elementattributelist' must be  */
+/*      initialized.  `trianglearealist' may be ignored.                     */
+/*    - `segmentlist' must be initialized if the `p' or `c' switch is used,  */
+/*      and the `P' switch is not used.  `segmentmarkerlist' must also be    */
+/*      initialized under these circumstances unless the `B' switch is used. */
+/*    - `edgelist' must be initialized if the `e' switch is used.            */
+/*      `edgemarkerlist' must be initialized if the `e' switch is used and   */
+/*      the `B' switch is not.                                               */
+/*    - `holelist', `regionlist', `normlist', and all scalars may be ignored.*/
+/*                                                                           */
+/*  `vorout' (only needed if `v' switch is used):                            */
+/*                                                                           */
+/*    - `pointlist' must be initialized.  If `in->numberofpointattributes'   */
+/*      is not zero, `pointattributelist' must be initialized.               */
+/*      `pointmarkerlist' may be ignored.                                    */
+/*    - `edgelist' and `normlist' must both be initialized.                  */
+/*      `edgemarkerlist' may be ignored.                                     */
+/*    - Everything else may be ignored.                                      */
+/*                                                                           */
+/*  After a call to triangulate(), the valid fields of `out' and `vorout'    */
+/*  will depend, in an obvious way, on the choice of switches used.  Note    */
+/*  that when the `p' switch is used, the pointers `holelist' and            */
+/*  `regionlist' are copied from `in' to `out', but no new space is          */
+/*  allocated; be careful that you don't free() the same array twice.  On    */
+/*  the other hand, Triangle will never copy the `pointlist' pointer (or any */
+/*  others); new space is allocated for `out->pointlist', or if the `N'      */
+/*  switch is used, `out->pointlist' remains uninitialized.                  */
+/*                                                                           */
+/*  All of the meaningful `numberof' fields will be properly set; for        */
+/*  instance, `numberofedges' will represent the number of edges in the      */
+/*  triangulation whether or not the edges were written.  If segments are    */
+/*  not used, `numberofsegments' will indicate the number of boundary edges. */
+/*                                                                           */
+/*****************************************************************************/
+
+struct triangulateio {
+  REAL *pointlist;                                               /* In / out */
+  REAL *pointattributelist;                                      /* In / out */
+  int *pointmarkerlist;                                          /* In / out */
+  int numberofpoints;                                            /* In / out */
+  int numberofpointattributes;                                   /* In / out */
+
+  int *trianglelist;                                             /* In / out */
+  REAL *triangleattributelist;                                   /* In / out */
+  REAL *trianglearealist;                                         /* In only */
+  int *neighborlist;                                             /* Out only */
+  int numberoftriangles;                                         /* In / out */
+  int numberofcorners;                                           /* In / out */
+  int numberoftriangleattributes;                                /* In / out */
+
+  int *segmentlist;                                              /* In / out */
+  int *segmentmarkerlist;                                        /* In / out */
+  int numberofsegments;                                          /* In / out */
+
+  REAL *holelist;                        /* In / pointer to array copied out */
+  int numberofholes;                                      /* In / copied out */
+
+  REAL *regionlist;                      /* In / pointer to array copied out */
+  int numberofregions;                                    /* In / copied out */
+
+  int *edgelist;                                                 /* Out only */
+  int *edgemarkerlist;            /* Not used with Voronoi diagram; out only */
+  REAL *normlist;                /* Used only with Voronoi diagram; out only */
+  int numberofedges;                                             /* Out only */
+};
+
+#ifdef ANSI_DECLARATORS
+void triangulate(char *, struct triangulateio *, struct triangulateio *,
+                 struct triangulateio *);
+#else /* not ANSI_DECLARATORS */
+void triangulate();
+#endif /* not ANSI_DECLARATORS */

diff --git a/Triangle/tricall.c b/Triangle/tricall.c
new file mode 100644 (file)
index 0000000..6beccdc
--- /dev/null
+++ b/Triangle/tricall.c
@@ -0,0 +1,279 @@
+/*****************************************************************************/
+/*                                                                           */
+/*  (tricall.c)                                                              */
+/*                                                                           */
+/*  Example program that demonstrates how to call Triangle.                  */
+/*                                                                           */
+/*  Accompanies Triangle Version 1.3                                         */
+/*  July 19, 1996                                                            */
+/*                                                                           */
+/*  This file is placed in the public domain (but the file that it calls     */
+/*  is still copyrighted!) by                                                */
+/*  Jonathan Richard Shewchuk                                                */
+/*  School of Computer Science                                               */
+/*  Carnegie Mellon University                                               */
+/*  5000 Forbes Avenue                                                       */
+/*  Pittsburgh, Pennsylvania  15213-3891                                     */
+/*  jrs@cs.cmu.edu                                                           */
+/*                                                                           */
+/*****************************************************************************/
+
+/* If SINGLE is defined when triangle.o is compiled, it should also be       */
+/*   defined here.  If not, it should not be defined here.                   */
+
+/* #define SINGLE */
+
+#ifdef SINGLE
+#define REAL float
+#else /* not SINGLE */
+#define REAL double
+#endif /* not SINGLE */
+
+#include <stdio.h>
+#include "triangle.h"
+
+#ifndef _STDLIB_H_
+extern void *malloc();
+extern void free();
+#endif /* _STDLIB_H_ */
+
+/*****************************************************************************/
+/*                                                                           */
+/*  report()   Print the input or output.                                    */
+/*                                                                           */
+/*****************************************************************************/
+
+void report(io, markers, reporttriangles, reportneighbors, reportsegments,
+            reportedges, reportnorms)
+struct triangulateio *io;
+int markers;
+int reporttriangles;
+int reportneighbors;
+int reportsegments;
+int reportedges;
+int reportnorms;
+{
+  int i, j;
+
+  for (i = 0; i < io->numberofpoints; i++) {
+    printf("Point %4d:", i);
+    for (j = 0; j < 2; j++) {
+      printf("  %.6g", io->pointlist[i * 2 + j]);
+    }
+    if (io->numberofpointattributes > 0) {
+      printf("   attributes");
+    }
+    for (j = 0; j < io->numberofpointattributes; j++) {
+      printf("  %.6g",
+             io->pointattributelist[i * io->numberofpointattributes + j]);
+    }
+    if (markers) {
+      printf("   marker %d\n", io->pointmarkerlist[i]);
+    } else {
+      printf("\n");
+    }
+  }
+  printf("\n");
+
+  if (reporttriangles || reportneighbors) {
+    for (i = 0; i < io->numberoftriangles; i++) {
+      if (reporttriangles) {
+        printf("Triangle %4d points:", i);
+        for (j = 0; j < io->numberofcorners; j++) {
+          printf("  %4d", io->trianglelist[i * io->numberofcorners + j]);
+        }
+        if (io->numberoftriangleattributes > 0) {
+          printf("   attributes");
+        }
+        for (j = 0; j < io->numberoftriangleattributes; j++) {
+          printf("  %.6g", io->triangleattributelist[i *
+                                         io->numberoftriangleattributes + j]);
+        }
+        printf("\n");
+      }
+      if (reportneighbors) {
+        printf("Triangle %4d neighbors:", i);
+        for (j = 0; j < 3; j++) {
+          printf("  %4d", io->neighborlist[i * 3 + j]);
+        }
+        printf("\n");
+      }
+    }
+    printf("\n");
+  }
+
+  if (reportsegments) {
+    for (i = 0; i < io->numberofsegments; i++) {
+      printf("Segment %4d points:", i);
+      for (j = 0; j < 2; j++) {
+        printf("  %4d", io->segmentlist[i * 2 + j]);
+      }
+      if (markers) {
+        printf("   marker %d\n", io->segmentmarkerlist[i]);
+      } else {
+        printf("\n");
+      }
+    }
+    printf("\n");
+  }
+
+  if (reportedges) {
+    for (i = 0; i < io->numberofedges; i++) {
+      printf("Edge %4d points:", i);
+      for (j = 0; j < 2; j++) {
+        printf("  %4d", io->edgelist[i * 2 + j]);
+      }
+      if (reportnorms && (io->edgelist[i * 2 + 1] == -1)) {
+        for (j = 0; j < 2; j++) {
+          printf("  %.6g", io->normlist[i * 2 + j]);
+        }
+      }
+      if (markers) {
+        printf("   marker %d\n", io->edgemarkerlist[i]);
+      } else {
+        printf("\n");
+      }
+    }
+    printf("\n");
+  }
+}
+
+/*****************************************************************************/
+/*                                                                           */
+/*  main()   Create and refine a mesh.                                       */
+/*                                                                           */
+/*****************************************************************************/
+
+int main()
+{
+  struct triangulateio in, mid, out, vorout;
+
+  /* Define input points. */
+
+  in.numberofpoints = 4;
+  in.numberofpointattributes = 1;
+  in.pointlist = (REAL *) malloc(in.numberofpoints * 2 * sizeof(REAL));
+  in.pointlist[0] = 0.0;
+  in.pointlist[1] = 0.0;
+  in.pointlist[2] = 1.0;
+  in.pointlist[3] = 0.0;
+  in.pointlist[4] = 1.0;
+  in.pointlist[5] = 10.0;
+  in.pointlist[6] = 0.0;
+  in.pointlist[7] = 10.0;
+  in.pointattributelist = (REAL *) malloc(in.numberofpoints *
+                                          in.numberofpointattributes *
+                                          sizeof(REAL));
+  in.pointattributelist[0] = 0.0;
+  in.pointattributelist[1] = 1.0;
+  in.pointattributelist[2] = 11.0;
+  in.pointattributelist[3] = 10.0;
+  in.pointmarkerlist = (int *) malloc(in.numberofpoints * sizeof(int));
+  in.pointmarkerlist[0] = 0;
+  in.pointmarkerlist[1] = 2;
+  in.pointmarkerlist[2] = 0;
+  in.pointmarkerlist[3] = 0;
+
+  in.numberofsegments = 0;
+  in.numberofholes = 0;
+  in.numberofregions = 1;
+  in.regionlist = (REAL *) malloc(in.numberofregions * 4 * sizeof(REAL));
+  in.regionlist[0] = 0.5;
+  in.regionlist[1] = 5.0;
+  in.regionlist[2] = 7.0;            /* Regional attribute (for whole mesh). */
+  in.regionlist[3] = 0.1;          /* Area constraint that will not be used. */
+
+  printf("Input point set:\n\n");
+  report(&in, 1, 0, 0, 0, 0, 0);
+
+  /* Make necessary initializations so that Triangle can return a */
+  /*   triangulation in `mid' and a voronoi diagram in `vorout'.  */
+
+  mid.pointlist = (REAL *) NULL;            /* Not needed if -N switch used. */
+  /* Not needed if -N switch used or number of point attributes is zero: */
+  mid.pointattributelist = (REAL *) NULL;
+  mid.pointmarkerlist = (int *) NULL; /* Not needed if -N or -B switch used. */
+  mid.trianglelist = (int *) NULL;          /* Not needed if -E switch used. */
+  /* Not needed if -E switch used or number of triangle attributes is zero: */
+  mid.triangleattributelist = (REAL *) NULL;
+  mid.neighborlist = (int *) NULL;         /* Needed only if -n switch used. */
+  /* Needed only if segments are output (-p or -c) and -P not used: */
+  mid.segmentlist = (int *) NULL;
+  /* Needed only if segments are output (-p or -c) and -P and -B not used: */
+  mid.segmentmarkerlist = (int *) NULL;
+  mid.edgelist = (int *) NULL;             /* Needed only if -e switch used. */
+  mid.edgemarkerlist = (int *) NULL;   /* Needed if -e used and -B not used. */
+
+  vorout.pointlist = (REAL *) NULL;        /* Needed only if -v switch used. */
+  /* Needed only if -v switch used and number of attributes is not zero: */
+  vorout.pointattributelist = (REAL *) NULL;
+  vorout.edgelist = (int *) NULL;          /* Needed only if -v switch used. */
+  vorout.normlist = (REAL *) NULL;         /* Needed only if -v switch used. */
+
+  /* Triangulate the points.  Switches are chosen to read and write a  */
+  /*   PSLG (p), preserve the convex hull (c), number everything from  */
+  /*   zero (z), assign a regional attribute to each element (A), and  */
+  /*   produce an edge list (e), a Voronoi diagram (v), and a triangle */
+  /*   neighbor list (n).                                              */
+
+  triangulate("pczAevn", &in, &mid, &vorout);
+
+  printf("Initial triangulation:\n\n");
+  report(&mid, 1, 1, 1, 1, 1, 0);
+  printf("Initial Voronoi diagram:\n\n");
+  report(&vorout, 0, 0, 0, 0, 1, 1);
+
+  /* Attach area constraints to the triangles in preparation for */
+  /*   refining the triangulation.                               */
+
+  /* Needed only if -r and -a switches used: */
+  mid.trianglearealist = (REAL *) malloc(mid.numberoftriangles * sizeof(REAL));
+  mid.trianglearealist[0] = 3.0;
+  mid.trianglearealist[1] = 1.0;
+
+  /* Make necessary initializations so that Triangle can return a */
+  /*   triangulation in `out'.                                    */
+
+  out.pointlist = (REAL *) NULL;            /* Not needed if -N switch used. */
+  /* Not needed if -N switch used or number of attributes is zero: */
+  out.pointattributelist = (REAL *) NULL;
+  out.trianglelist = (int *) NULL;          /* Not needed if -E switch used. */
+  /* Not needed if -E switch used or number of triangle attributes is zero: */
+  out.triangleattributelist = (REAL *) NULL;
+
+  /* Refine the triangulation according to the attached */
+  /*   triangle area constraints.                       */
+
+  triangulate("prazBP", &mid, &out, (struct triangulateio *) NULL);
+
+  printf("Refined triangulation:\n\n");
+  report(&out, 0, 1, 0, 0, 0, 0);
+
+  /* Free all allocated arrays, including those allocated by Triangle. */
+
+  free(in.pointlist);
+  free(in.pointattributelist);
+  free(in.pointmarkerlist);
+  free(in.regionlist);
+  free(mid.pointlist);
+  free(mid.pointattributelist);
+  free(mid.pointmarkerlist);
+  free(mid.trianglelist);
+  free(mid.triangleattributelist);
+  free(mid.trianglearealist);
+  free(mid.neighborlist);
+  free(mid.segmentlist);
+  free(mid.segmentmarkerlist);
+  free(mid.edgelist);
+  free(mid.edgemarkerlist);
+  free(vorout.pointlist);
+  free(vorout.pointattributelist);
+  free(vorout.edgelist);
+  free(vorout.normlist);
+  free(out.pointlist);
+  free(out.pointattributelist);
+  free(out.trianglelist);
+  free(out.triangleattributelist);
+
+  return 0;
+}