[gtk+] Bug 622333 - Crash in gdk_window_impl_quartz_begin_paint_region

[Kristian Rietveld <kristian src gnome org>]

commit 98d47b57bffd545ab32e656ab91740a89baac992
Author: John Ralls <jralls ceridwen us>
Date:   Sat Jun 26 18:17:30 2010 +0200

    Bug 622333 - Crash in gdk_window_impl_quartz_begin_paint_region
    
    (cherry picked from commit 093a867e51b383b5c1877415b410cc3c122c72da)

 gdk/quartz/gdkwindow-quartz.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/gdk/quartz/gdkwindow-quartz.c b/gdk/quartz/gdkwindow-quartz.c
index 8de986c..da4e8c9 100644
--- a/gdk/quartz/gdkwindow-quartz.c
+++ b/gdk/quartz/gdkwindow-quartz.c
@@ -259,6 +259,9 @@ gdk_window_impl_quartz_begin_paint_region (GdkPaintable    *paintable,
 
   gdk_region_get_rectangles (clipped_and_offset_region, &rects, &n_rects);
 
+  if (n_rects == 0)
+    goto done;
+
   if (bg_pixmap == NULL)
     {
       CGContextRef cg_context;