From d5404dea25123567e9645d3e88a6cd0c14b2073f Mon Sep 17 00:00:00 2001
From: Greg Ercolano <erco@seriss.com>
Date: Mon, 8 Apr 2013 18:24:17 +0000
Subject: [PATCH] Fix for STR #2944 [2]: Fix Apple-specifc nested window
 problem for Fl_Gl_Window's.

                       Added new method Fl_Widget::window_offset(x,y)
		       to access the top-level window offset of the current widget.

		       Open to alternative names for the new method.



git-svn-id: file:///fltk/svn/fltk/branches/branch-1.3@9866 ea41ed52-d2ee-0310-a9c1-e6b18d33e121
---
 FL/Fl_Window.H       |  1 +
 src/Fl_Gl_Window.cxx |  6 ++++--
 src/Fl_Window.cxx    | 15 +++++++++++++++
 3 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/FL/Fl_Window.H b/FL/Fl_Window.H
index d6997e601..8b2f8196a 100644
--- a/FL/Fl_Window.H
+++ b/FL/Fl_Window.H
@@ -120,6 +120,7 @@ protected:
     \see force_position(int)
   */
   int force_position() const { return ((flags() & FORCE_POSITION)?1:0); }
+  Fl_Window* window_offset(int& xoff, int& yoff) const;
 
 public:
 
diff --git a/src/Fl_Gl_Window.cxx b/src/Fl_Gl_Window.cxx
index 355865ab1..441dea78a 100644
--- a/src/Fl_Gl_Window.cxx
+++ b/src/Fl_Gl_Window.cxx
@@ -183,8 +183,10 @@ void Fl_Gl_Window::make_current() {
   GLint xywh[4];
 
   if (window()) {
-    xywh[0] = x();
-    xywh[1] = window()->h() - y() - h();
+    int xoff,yoff;
+    const Fl_Window *win = window_offset(xoff, yoff);	// STR #2944 [2]
+    xywh[0] = xoff;
+    xywh[1] = win->h() - yoff - h();
   } else {
     xywh[0] = 0;
     xywh[1] = 0;
diff --git a/src/Fl_Window.cxx b/src/Fl_Window.cxx
index 20bb520fd..b6e5985bc 100644
--- a/src/Fl_Window.cxx
+++ b/src/Fl_Window.cxx
@@ -278,6 +278,21 @@ void Fl_Window::icon(const void * ic) {
   icon_ = ic;
 }
 
+/**
+  Finds the x/y offset of the current window relative to the top-level window.
+  \param[out] xoff,yoff Returns the x/y offset
+  \returns the top-level window
+*/
+Fl_Window* Fl_Window::window_offset(int& xoff, int& yoff) const {
+  xoff = yoff = 0;
+  const Fl_Window *win = (const Fl_Window*)this;
+  while (win && win->window()) {
+    xoff += win->x();			// accumulate offsets
+    yoff += win->y();
+    win = win->window();		// walk up window hierarchy
+  }
+  return (Fl_Window*)win;
+}
 
 //
 // End of "$Id$".