Fixed OpenGL hide/show issue in OS X (STR #2260)

git-svn-id: file:///fltk/svn/fltk/branches/branch-1.3@7831 ea41ed52-d2ee-0310-a9c1-e6b18d33e121

CHANGES

@@ -1,5 +1,6 @@
 CHANGES IN FLTK 1.3.0
 
+	- Fixed OpenGL hide/show issue in OS X (STR #2260)
 	- Added visual feedback for button shortcuts (STR #2372)
 	- Fixed internationalisation of menus using FLuid (STR #2246)
 	- Fixed blinking of selection when the mouse was dragged 

FL/Fl_Gl_Window.H

@@ -87,7 +87,8 @@ public:
   void flush();
   void hide();
   void resize(int,int,int,int);
-
+  int handle(int);
+  
   /**
     Is turned off when FLTK creates a new context for this window or 
     when the window resizes, and is turned on \e after draw() is called.

src/Fl_Gl_Window.cxx

@@ -522,6 +522,28 @@ void Fl_Gl_Window::draw_overlay() {}
 void Fl_Gl_Window::draw() {
     Fl::fatal("Fl_Gl_Window::draw() *must* be overriden. Please refer to the documentation.");
 }
+
+
+/**
+ Handle some FLTK events as needed.
+ */
+int Fl_Gl_Window::handle(int event) 
+{
+#if (__APPLE_QUARTZ__)
+  if (event==FL_HIDE) {
+    // if we are not hidden, just the parent was hidden, so we must throw away the context
+    if (!visible_r())
+      context(0); // remove context wthout setting the hidden flags
+  }
+  if (event==FL_SHOW) {
+    // if we are not hidden, just the parent was shown, so we must create a new context
+    if (visible_r())
+      show(); //
+  }
+#endif
+  return Fl_Window::handle(event);
+}
+
 //
 // End of "$Id$".
 //