From e79e70062e11e34842a4ee42ce31df6fabea0eb7 Mon Sep 17 00:00:00 2001
From: Thomas Geymayer <tomgey@gmail.com>
Date: Fri, 26 Jul 2013 23:48:13 +0200
Subject: [PATCH] Canvas window: increase drag accuracy.

---
 src/Canvas/gui_mgr.cxx |  9 ++++++---
 src/Canvas/window.cxx  | 11 ++++++-----
 src/Canvas/window.hxx  |  3 ++-
 3 files changed, 14 insertions(+), 9 deletions(-)

diff --git a/src/Canvas/gui_mgr.cxx b/src/Canvas/gui_mgr.cxx
index 3188430e3..b501a2a40 100644
--- a/src/Canvas/gui_mgr.cxx
+++ b/src/Canvas/gui_mgr.cxx
@@ -116,6 +116,7 @@ class DesktopGroup:
     uint8_t _resize;
     int     _last_cursor;
 
+    osg::Vec2 _drag_start;
     float _last_x,
           _last_y;
     double _last_scroll_time;
@@ -302,7 +303,8 @@ bool DesktopGroup::handleMouse(const osgGA::GUIEventAdapter& ea)
         _resize_window.reset();
         break;
       case osgGA::GUIEventAdapter::DRAG:
-        _resize_window.lock()->handleResize(_resize, event->delta);
+        _resize_window.lock()->handleResize( _resize,
+                                             event->screen_pos - _drag_start );
         return true;
       default:
         return false;
@@ -379,9 +381,10 @@ bool DesktopGroup::handleMouse(const osgGA::GUIEventAdapter& ea)
       if( ea.getEventType() == osgGA::GUIEventAdapter::PUSH )
       {
         _resize_window = window_at_cursor;
+        _drag_start = event->screen_pos;
+
         window_at_cursor->raise();
-        window_at_cursor->handleResize( _resize | canvas::Window::INIT,
-                                        event->delta );
+        window_at_cursor->handleResize(_resize | canvas::Window::INIT);
       }
 
       return true;
diff --git a/src/Canvas/window.cxx b/src/Canvas/window.cxx
index 653427272..ab02db9ad 100644
--- a/src/Canvas/window.cxx
+++ b/src/Canvas/window.cxx
@@ -163,7 +163,8 @@ namespace canvas
   }
 
   //----------------------------------------------------------------------------
-  void Window::handleResize(uint8_t mode, const osg::Vec2f& delta)
+  void Window::handleResize( uint8_t mode,
+                             const osg::Vec2f& offset )
   {
     if( mode == NONE )
     {
@@ -180,14 +181,14 @@ namespace canvas
     }
 
     if( mode & BOTTOM )
-      _resize_bottom += delta.y();
+      _resize_bottom = getRegion().b() + offset.y();
     else if( mode & TOP )
-      _resize_top += delta.y();
+      _resize_top = getRegion().t() + offset.y();
 
     if( mode & canvas::Window::RIGHT )
-      _resize_right += delta.x();
+      _resize_right = getRegion().r() + offset.x();
     else if( mode & canvas::Window::LEFT )
-      _resize_left += delta.x();
+      _resize_left = getRegion().l() + offset.x();
   }
 
   //----------------------------------------------------------------------------
diff --git a/src/Canvas/window.hxx b/src/Canvas/window.hxx
index 23c483522..ece277281 100644
--- a/src/Canvas/window.hxx
+++ b/src/Canvas/window.hxx
@@ -76,7 +76,8 @@ namespace canvas
        */
       void raise();
 
-      void handleResize(uint8_t mode, const osg::Vec2f& delta = osg::Vec2f());
+      void handleResize( uint8_t mode,
+                         const osg::Vec2f& offset = osg::Vec2f() );
 
     protected:
 
-- 
2.39.5