1 // panel_io.cxx - I/O for 2D panel.
3 // Written by David Megginson, started January 2000.
5 // This program is free software; you can redistribute it and/or
6 // modify it under the terms of the GNU General Public License as
7 // published by the Free Software Foundation; either version 2 of the
8 // License, or (at your option) any later version.
10 // This program is distributed in the hope that it will be useful, but
11 // WITHOUT ANY WARRANTY; without even the implied warranty of
12 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 // General Public License for more details.
15 // You should have received a copy of the GNU General Public License
16 // along with this program; if not, write to the Free Software
17 // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
29 #include <string.h> // for strcmp()
31 #include <simgear/compiler.h>
32 #include <simgear/structure/exception.hxx>
33 #include <simgear/debug/logstream.hxx>
34 #include <simgear/misc/sg_path.hxx>
35 #include <simgear/props/props.hxx>
41 #include <Main/globals.hxx>
42 #include <Main/fg_props.hxx>
46 // #include "panel.hxx"
47 #include "panel_io.hxx"
48 #include <Instrumentation/KLN89/kln89.hxx>
51 #include "built_in/FGMagRibbon.hxx"
53 SG_USING_STD(istream);
54 SG_USING_STD(ifstream);
59 ////////////////////////////////////////////////////////////////////////
60 // Read and construct a panel.
62 // The panel is specified as a regular property list, and each of the
63 // instruments is its own, separate property list (and thus, a separate
64 // XML document). The functions in this section read in the files
65 // as property lists, then extract properties to set up the panel
68 // A panel contains zero or more instruments.
70 // An instrument contains one or more layers and zero or more actions.
72 // A layer contains zero or more transformations.
74 // Some special types of layers also contain other objects, such as
75 // chunks of text or other layers.
77 // There are currently four types of layers:
79 // 1. Textured Layer (type="texture"), the default
80 // 2. Text Layer (type="text")
81 // 3. Switch Layer (type="switch")
82 // 4. Built-in Layer (type="built-in", must also specify class)
84 // The only built-in layer so far is the ribbon for the magnetic compass
85 // (class="compass-ribbon").
87 // There are three types of actions:
89 // 1. Adjust (type="adjust"), the default
90 // 2. Swap (type="swap")
91 // 3. Toggle (type="toggle")
93 // There are three types of transformations:
95 // 1. X shift (type="x-shift"), the default
96 // 2. Y shift (type="y-shift")
97 // 3. Rotation (type="rotation")
99 // Each of these may be associated with a property, so that a needle
100 // will rotate with the airspeed, for example, or may have a fixed
101 // floating-point value.
102 ////////////////////////////////////////////////////////////////////////
106 * Read a cropped texture from the instrument's property list.
108 * The x1 and y1 properties give the starting position of the texture
109 * (between 0.0 and 1.0), and the the x2 and y2 properties give the
110 * ending position. For example, to use the bottom-left quarter of a
111 * texture, x1=0.0, y1=0.0, x2=0.5, y2=0.5.
113 static FGCroppedTexture
114 readTexture (const SGPropertyNode * node)
116 FGCroppedTexture texture(node->getStringValue("path"),
117 node->getFloatValue("x1"),
118 node->getFloatValue("y1"),
119 node->getFloatValue("x2", 1.0),
120 node->getFloatValue("y2", 1.0));
121 SG_LOG(SG_COCKPIT, SG_DEBUG, "Read texture " << node->getName());
127 * Test for a condition in the current node.
130 ////////////////////////////////////////////////////////////////////////
131 // Read a condition and use it if necessary.
132 ////////////////////////////////////////////////////////////////////////
135 readConditions (SGConditional *component, const SGPropertyNode *node)
137 const SGPropertyNode * conditionNode = node->getChild("condition");
138 if (conditionNode != 0)
139 // The top level is implicitly AND
140 component->setCondition(sgReadCondition(globals->get_props(),
146 * Read an action from the instrument's property list.
148 * The action will be performed when the user clicks a mouse button
149 * within the specified region of the instrument. Actions always work
150 * by modifying the value of a property (see the SGPropertyNode
153 * The following action types are defined:
155 * "adjust" - modify the value of a floating-point property by
156 * the increment specified. This is the default.
158 * "swap" - swap the values of two-floating-point properties.
160 * "toggle" - toggle the value of a boolean property between true and
163 * For the adjust action, it is possible to specify an increment
164 * (use a negative number for a decrement), a minimum allowed value,
165 * a maximum allowed value, and a flag to indicate whether the value
166 * should freeze or wrap-around when it reachs the minimum or maximum.
168 * The action will be scaled automatically if the instrument is not
169 * being drawn at its regular size.
171 static FGPanelAction *
172 readAction (const SGPropertyNode * node, float w_scale, float h_scale)
175 SGPropertyNode *binding;
176 vector<SGPropertyNode_ptr>bindings = node->getChildren("binding");
178 // button-less actions are fired initially
179 if (!node->hasValue("w") || !node->hasValue("h")) {
180 for (i = 0; i < bindings.size(); i++) {
181 SGBinding b(bindings[i], globals->get_props());
187 string name = node->getStringValue("name");
189 int button = node->getIntValue("button");
190 int x = int(node->getIntValue("x") * w_scale);
191 int y = int(node->getIntValue("y") * h_scale);
192 int w = int(node->getIntValue("w") * w_scale);
193 int h = int(node->getIntValue("h") * h_scale);
194 bool repeatable = node->getBoolValue("repeatable", true);
196 FGPanelAction * action = new FGPanelAction(button, x, y, w, h, repeatable);
198 SGPropertyNode * dest = fgGetNode("/sim/bindings/panel", true);
200 for (i = 0; i < bindings.size(); i++) {
201 SG_LOG(SG_INPUT, SG_INFO, "Reading binding "
202 << bindings[i]->getStringValue("command"));
205 while (dest->getChild("binding", j))
208 binding = dest->getChild("binding", j, true);
209 copyProperties(bindings[i], binding);
210 action->addBinding(new SGBinding(binding, globals->get_props()), 0);
213 if (node->hasChild("mod-up")) {
214 bindings = node->getChild("mod-up")->getChildren("binding");
215 for (i = 0; i < bindings.size(); i++) {
217 while (dest->getChild("binding", j))
220 binding = dest->getChild("binding", j, true);
221 copyProperties(bindings[i], binding);
222 action->addBinding(new SGBinding(binding, globals->get_props()), 1);
226 readConditions(action, node);
232 * Read a transformation from the instrument's property list.
234 * The panel module uses the transformations to slide or spin needles,
235 * knobs, and other indicators, and to place layers in the correct
236 * positions. Every layer starts centered exactly on the x,y co-ordinate,
237 * and many layers need to be moved or rotated simply to display the
238 * instrument correctly.
240 * There are three types of transformations:
242 * "x-shift" - move the layer horizontally.
244 * "y-shift" - move the layer vertically.
246 * "rotation" - rotate the layer.
248 * Each transformation may have a fixed offset, and may also have
249 * a floating-point property value to add to the offset. The
250 * floating-point property may be clamped to a minimum and/or
251 * maximum range and scaled (after clamping).
253 * Note that because of the way OpenGL works, transformations will
254 * appear to be applied backwards.
256 static FGPanelTransformation *
257 readTransformation (const SGPropertyNode * node, float w_scale, float h_scale)
259 FGPanelTransformation * t = new FGPanelTransformation;
261 string name = node->getName();
262 string type = node->getStringValue("type");
263 string propName = node->getStringValue("property", "");
264 SGPropertyNode * target = 0;
267 SG_LOG( SG_COCKPIT, SG_INFO,
268 "No type supplied for transformation " << name
269 << " assuming \"rotation\"" );
273 if (!propName.empty()) {
274 target = fgGetNode(propName.c_str(), true);
278 t->min = node->getFloatValue("min", -9999999);
279 t->max = node->getFloatValue("max", 99999999);
280 t->has_mod = node->hasChild("modulator");
282 t->mod = node->getFloatValue("modulator");
283 t->factor = node->getFloatValue("scale", 1.0);
284 t->offset = node->getFloatValue("offset", 0.0);
286 // Check for an interpolation table
287 const SGPropertyNode * trans_table = node->getNode("interpolation");
288 if (trans_table != 0) {
289 SG_LOG( SG_COCKPIT, SG_INFO, "Found interpolation table with "
290 << trans_table->nChildren() << " children" );
291 t->table = new SGInterpTable(trans_table);
296 // Move the layer horizontally.
297 if (type == "x-shift") {
298 t->type = FGPanelTransformation::XSHIFT;
299 // t->min *= w_scale; //removed by Martin Dressler
300 // t->max *= w_scale; //removed by Martin Dressler
301 t->offset *= w_scale;
302 t->factor *= w_scale; //Added by Martin Dressler
305 // Move the layer vertically.
306 else if (type == "y-shift") {
307 t->type = FGPanelTransformation::YSHIFT;
308 //t->min *= h_scale; //removed
309 //t->max *= h_scale; //removed
310 t->offset *= h_scale;
311 t->factor *= h_scale; //Added
314 // Rotate the layer. The rotation
315 // is in degrees, and does not need
316 // to scale with the instrument size.
317 else if (type == "rotation") {
318 t->type = FGPanelTransformation::ROTATION;
322 SG_LOG( SG_COCKPIT, SG_ALERT, "Unrecognized transformation type " << type );
327 readConditions(t, node);
328 SG_LOG( SG_COCKPIT, SG_DEBUG, "Read transformation " << name );
334 * Read a chunk of text from the instrument's property list.
336 * A text layer consists of one or more chunks of text. All chunks
337 * share the same font size and color (and eventually, font), but
338 * each can come from a different source. There are three types of
341 * "literal" - a literal text string (the default)
343 * "text-value" - the current value of a string property
345 * "number-value" - the current value of a floating-point property.
347 * All three may also include a printf-style format string.
350 readTextChunk (const SGPropertyNode * node)
352 FGTextLayer::Chunk * chunk;
353 string name = node->getStringValue("name");
354 string type = node->getStringValue("type");
355 string format = node->getStringValue("format");
357 // Default to literal text.
359 SG_LOG( SG_COCKPIT, SG_INFO, "No type provided for text chunk " << name
360 << " assuming \"literal\"");
364 // A literal text string.
365 if (type == "literal") {
366 string text = node->getStringValue("text");
367 chunk = new FGTextLayer::Chunk(text, format);
370 // The value of a string property.
371 else if (type == "text-value") {
372 SGPropertyNode * target =
373 fgGetNode(node->getStringValue("property"), true);
374 chunk = new FGTextLayer::Chunk(FGTextLayer::TEXT_VALUE, target, format);
377 // The value of a float property.
378 else if (type == "number-value") {
379 string propName = node->getStringValue("property");
380 float scale = node->getFloatValue("scale", 1.0);
381 float offset = node->getFloatValue("offset", 0.0);
382 bool truncation = node->getBoolValue("truncate", false);
383 SGPropertyNode * target = fgGetNode(propName.c_str(), true);
384 chunk = new FGTextLayer::Chunk(FGTextLayer::DOUBLE_VALUE, target,
385 format, scale, offset, truncation);
390 SG_LOG( SG_COCKPIT, SG_ALERT, "Unrecognized type " << type
391 << " for text chunk " << name );
395 readConditions(chunk, node);
401 * Read a single layer from an instrument's property list.
403 * Each instrument consists of one or more layers stacked on top
404 * of each other; the lower layers show through only where the upper
405 * layers contain an alpha component. Each layer can be moved
406 * horizontally and vertically and rotated using transformations.
408 * This module currently recognizes four kinds of layers:
410 * "texture" - a layer containing a texture (the default)
412 * "text" - a layer containing text
414 * "switch" - a layer that switches between two other layers
415 * based on the current value of a boolean property.
417 * "built-in" - a hard-coded layer supported by C++ code in FlightGear.
419 * Currently, the only built-in layer class is "compass-ribbon".
421 static FGInstrumentLayer *
422 readLayer (const SGPropertyNode * node, float w_scale, float h_scale)
424 FGInstrumentLayer * layer = NULL;
425 string name = node->getStringValue("name");
426 string type = node->getStringValue("type");
427 int w = node->getIntValue("w", -1);
428 int h = node->getIntValue("h", -1);
429 bool emissive = node->getBoolValue("emissive", false);
431 w = int(w * w_scale);
433 h = int(h * h_scale);
437 SG_LOG( SG_COCKPIT, SG_INFO,
438 "No type supplied for layer " << name
439 << " assuming \"texture\"" );
444 // A textured instrument layer.
445 if (type == "texture") {
446 FGCroppedTexture texture = readTexture(node->getNode("texture"));
447 layer = new FGTexturedLayer(texture, w, h);
449 FGTexturedLayer *tl=(FGTexturedLayer*)layer;
450 tl->setEmissive(true);
455 // A group of sublayers.
456 else if (type == "group") {
457 layer = new FGGroupLayer();
458 for (int i = 0; i < node->nChildren(); i++) {
459 const SGPropertyNode * child = node->getChild(i);
460 if (!strcmp(child->getName(), "layer"))
461 ((FGGroupLayer *)layer)->addLayer(readLayer(child, w_scale, h_scale));
466 // A textual instrument layer.
467 else if (type == "text") {
468 FGTextLayer * tlayer = new FGTextLayer(w, h); // FIXME
470 // Set the text color.
471 float red = node->getFloatValue("color/red", 0.0);
472 float green = node->getFloatValue("color/green", 0.0);
473 float blue = node->getFloatValue("color/blue", 0.0);
474 tlayer->setColor(red, green, blue);
476 // Set the point size.
477 float pointSize = node->getFloatValue("point-size", 10.0) * w_scale;
478 tlayer->setPointSize(pointSize);
481 string fontName = node->getStringValue("font", "Helvetica");
482 tlayer->setFontName(fontName);
484 const SGPropertyNode * chunk_group = node->getNode("chunks");
485 if (chunk_group != 0) {
486 int nChunks = chunk_group->nChildren();
487 for (int i = 0; i < nChunks; i++) {
488 const SGPropertyNode * node = chunk_group->getChild(i);
489 if (!strcmp(node->getName(), "chunk")) {
490 FGTextLayer::Chunk * chunk = readTextChunk(node);
492 tlayer->addChunk(chunk);
494 SG_LOG( SG_COCKPIT, SG_INFO, "Skipping " << node->getName()
502 // A switch instrument layer.
503 else if (type == "switch") {
504 layer = new FGSwitchLayer();
505 for (int i = 0; i < node->nChildren(); i++) {
506 const SGPropertyNode * child = node->getChild(i);
507 if (!strcmp(child->getName(), "layer"))
508 ((FGGroupLayer *)layer)->addLayer(readLayer(child, w_scale, h_scale));
512 // A built-in instrument layer.
513 else if (type == "built-in") {
514 string layerclass = node->getStringValue("class");
516 if (layerclass == "mag-ribbon") {
517 layer = new FGMagRibbon(w, h);
520 else if (layerclass.empty()) {
521 SG_LOG( SG_COCKPIT, SG_ALERT, "No class provided for built-in layer "
527 SG_LOG( SG_COCKPIT, SG_ALERT, "Unknown built-in layer class "
535 SG_LOG( SG_COCKPIT, SG_ALERT, "Unrecognized layer type " << type );
541 // Get the transformations for each layer.
543 const SGPropertyNode * trans_group = node->getNode("transformations");
544 if (trans_group != 0) {
545 int nTransformations = trans_group->nChildren();
546 for (int i = 0; i < nTransformations; i++) {
547 const SGPropertyNode * node = trans_group->getChild(i);
548 if (!strcmp(node->getName(), "transformation")) {
549 FGPanelTransformation * t = readTransformation(node, w_scale, h_scale);
551 layer->addTransformation(t);
553 SG_LOG( SG_COCKPIT, SG_INFO, "Skipping " << node->getName()
554 << " in transformations" );
559 readConditions(layer, node);
560 SG_LOG( SG_COCKPIT, SG_DEBUG, "Read layer " << name );
566 * Read an instrument from a property list.
568 * The instrument consists of a preferred width and height
569 * (the panel may override these), together with a list of layers
570 * and a list of actions to be performed when the user clicks
571 * the mouse over the instrument. All co-ordinates are relative
572 * to the instrument's position, so instruments are fully relocatable;
573 * likewise, co-ordinates for actions and transformations will be
574 * scaled automatically if the instrument is not at its preferred size.
576 static FGPanelInstrument *
577 readInstrument (const SGPropertyNode * node)
579 const string name = node->getStringValue("name");
580 int x = node->getIntValue("x", -1);
581 int y = node->getIntValue("y", -1);
582 int real_w = node->getIntValue("w", -1);
583 int real_h = node->getIntValue("h", -1);
584 int w = node->getIntValue("w-base", -1);
585 int h = node->getIntValue("h-base", -1);
587 if (x == -1 || y == -1) {
588 SG_LOG( SG_COCKPIT, SG_ALERT,
589 "x and y positions must be specified and > 0" );
596 w_scale = float(real_w) / float(w);
600 h_scale = float(real_h) / float(h);
604 SG_LOG( SG_COCKPIT, SG_DEBUG, "Reading instrument " << name );
606 FGLayeredInstrument * instrument =
607 new FGLayeredInstrument(x, y, w, h);
610 // Get the actions for the instrument.
612 const SGPropertyNode * action_group = node->getNode("actions");
613 if (action_group != 0) {
614 int nActions = action_group->nChildren();
615 for (int i = 0; i < nActions; i++) {
616 const SGPropertyNode * node = action_group->getChild(i);
617 if (!strcmp(node->getName(), "action")) {
618 FGPanelAction * action = readAction(node, w_scale, h_scale);
620 instrument->addAction(action);
622 SG_LOG( SG_COCKPIT, SG_INFO, "Skipping " << node->getName()
629 // Get the layers for the instrument.
631 const SGPropertyNode * layer_group = node->getNode("layers");
632 if (layer_group != 0) {
633 int nLayers = layer_group->nChildren();
634 for (int i = 0; i < nLayers; i++) {
635 const SGPropertyNode * node = layer_group->getChild(i);
636 if (!strcmp(node->getName(), "layer")) {
637 FGInstrumentLayer * layer = readLayer(node, w_scale, h_scale);
639 instrument->addLayer(layer);
641 SG_LOG( SG_COCKPIT, SG_INFO, "Skipping " << node->getName()
647 readConditions(instrument, node);
648 SG_LOG( SG_COCKPIT, SG_DEBUG, "Done reading instrument " << name );
654 * Construct the panel from a property tree.
657 readPanel (const SGPropertyNode * root)
659 SG_LOG( SG_COCKPIT, SG_INFO, "Reading properties for panel " <<
660 root->getStringValue("name", "[Unnamed Panel]") );
662 FGPanel * panel = new FGPanel();
663 panel->setWidth(root->getIntValue("w", 1024));
664 panel->setHeight(root->getIntValue("h", 443));
667 // Grab the visible external viewing area, default to
669 panel->setViewHeight(root->getIntValue("view-height",
670 768 - panel->getHeight() + 2));
673 // Grab the panel's initial offsets, default to 0, 0.
675 if (!fgHasNode("/sim/panel/x-offset"))
676 fgSetInt("/sim/panel/x-offset", root->getIntValue("x-offset", 0));
678 // conditional removed by jim wilson to allow panel xml code
679 // with y-offset defined to work...
680 if (!fgHasNode("/sim/panel/y-offset"))
681 fgSetInt("/sim/panel/y-offset", root->getIntValue("y-offset", 0));
684 // Assign the background texture, if any, or a bogus chequerboard.
686 string bgTexture = root->getStringValue("background");
687 if (bgTexture.empty())
689 panel->setBackground(FGTextureManager::createTexture(bgTexture.c_str()));
690 SG_LOG( SG_COCKPIT, SG_INFO, "Set background texture to " << bgTexture );
693 // Get multibackground if any...
695 string mbgTexture = root->getStringValue("multibackground[0]");
696 if (!mbgTexture.empty()) {
697 panel->setMultiBackground(FGTextureManager::createTexture(mbgTexture.c_str()), 0);
698 SG_LOG( SG_COCKPIT, SG_INFO, "Set background texture to " << mbgTexture );
700 mbgTexture = root->getStringValue("multibackground[1]");
701 if (mbgTexture.empty())
703 panel->setMultiBackground(FGTextureManager::createTexture(mbgTexture.c_str()), 1);
704 SG_LOG( SG_COCKPIT, SG_INFO, "Set background texture to " << mbgTexture );
706 mbgTexture = root->getStringValue("multibackground[2]");
707 if (mbgTexture.empty())
709 panel->setMultiBackground(FGTextureManager::createTexture(mbgTexture.c_str()), 2);
710 SG_LOG( SG_COCKPIT, SG_INFO, "Set background texture to " << mbgTexture );
712 mbgTexture = root->getStringValue("multibackground[3]");
713 if (mbgTexture.empty())
715 panel->setMultiBackground(FGTextureManager::createTexture(mbgTexture.c_str()), 3);
716 SG_LOG( SG_COCKPIT, SG_INFO, "Set background texture to " << mbgTexture );
718 mbgTexture = root->getStringValue("multibackground[4]");
719 if (mbgTexture.empty())
721 panel->setMultiBackground(FGTextureManager::createTexture(mbgTexture.c_str()), 4);
722 SG_LOG( SG_COCKPIT, SG_INFO, "Set background texture to " << mbgTexture );
724 mbgTexture = root->getStringValue("multibackground[5]");
725 if (mbgTexture.empty())
727 panel->setMultiBackground(FGTextureManager::createTexture(mbgTexture.c_str()), 5);
728 SG_LOG( SG_COCKPIT, SG_INFO, "Set background texture to " << mbgTexture );
730 mbgTexture = root->getStringValue("multibackground[6]");
731 if (mbgTexture.empty())
733 panel->setMultiBackground(FGTextureManager::createTexture(mbgTexture.c_str()), 6);
734 SG_LOG( SG_COCKPIT, SG_INFO, "Set background texture to " << mbgTexture );
736 mbgTexture = root->getStringValue("multibackground[7]");
737 if (mbgTexture.empty())
739 panel->setMultiBackground(FGTextureManager::createTexture(mbgTexture.c_str()), 7);
740 SG_LOG( SG_COCKPIT, SG_INFO, "Set background texture to " << mbgTexture );
747 // Create each instrument.
749 SG_LOG( SG_COCKPIT, SG_INFO, "Reading panel instruments" );
750 const SGPropertyNode * instrument_group = root->getChild("instruments");
751 if (instrument_group != 0) {
752 int nInstruments = instrument_group->nChildren();
753 for (int i = 0; i < nInstruments; i++) {
754 const SGPropertyNode * node = instrument_group->getChild(i);
755 if (!strcmp(node->getName(), "instrument")) {
756 FGPanelInstrument * instrument = readInstrument(node);
758 panel->addInstrument(instrument);
759 } else if (!strcmp(node->getName(), "special-instrument")) {
760 //cout << "Special instrument found in instruments section!\n";
761 const string name = node->getStringValue("name");
762 if (name == "KLN89 GPS") {
763 //cout << "Special instrument is KLN89\n";
765 int x = node->getIntValue("x", -1);
766 int y = node->getIntValue("y", -1);
767 int real_w = node->getIntValue("w", -1);
768 int real_h = node->getIntValue("h", -1);
769 int w = node->getIntValue("w-base", -1);
770 int h = node->getIntValue("h-base", -1);
772 if (x == -1 || y == -1) {
773 SG_LOG( SG_COCKPIT, SG_ALERT,
774 "x and y positions must be specified and > 0" );
781 w_scale = float(real_w) / float(w);
785 h_scale = float(real_h) / float(h);
789 SG_LOG( SG_COCKPIT, SG_DEBUG, "Reading instrument " << name );
791 // Warning - hardwired size!!!
792 RenderArea2D* instrument = new RenderArea2D(158, 40, 158, 40, x, y);
793 KLN89* gps = (KLN89*)globals->get_subsystem("kln89");
795 gps = new KLN89(instrument);
796 globals->add_subsystem("kln89", gps);
798 //gps->init(); // init seems to get called automagically.
799 FGSpecialInstrument* gpsinst = new FGSpecialInstrument(gps);
800 panel->addInstrument(gpsinst);
802 SG_LOG( SG_COCKPIT, SG_WARN, "Unknown special instrument found" );
805 SG_LOG( SG_COCKPIT, SG_INFO, "Skipping " << node->getName()
806 << " in instruments section" );
810 SG_LOG( SG_COCKPIT, SG_INFO, "Done reading panel instruments" );
814 // Return the new panel.
821 * Read a panel from a property list.
823 * Each panel instrument will appear in its own, separate
824 * property list. The top level simply names the panel and
825 * places the instruments in their appropriate locations (and
826 * optionally resizes them if necessary).
828 * Returns 0 if the read fails for any reason.
831 fgReadPanel (istream &input)
836 readProperties(input, &root);
837 } catch (const sg_exception &e) {
838 guiErrorMessage("Error reading panel: ", e);
841 return readPanel(&root);
846 * Read a panel from a property list.
848 * This function opens a stream to a file, then invokes the
849 * main fgReadPanel() function.
852 fgReadPanel (const string &relative_path)
854 SGPath path(globals->get_fg_root());
855 path.append(relative_path);
859 readProperties(path.str(), &root);
860 } catch (const sg_exception &e) {
861 guiErrorMessage("Error reading panel: ", e);
864 return readPanel(&root);
869 // end of panel_io.cxx