[gtk+] gdk: Use CAIRO_OPERATOR_SOURCE when painting double-buffered buffer

[Benjamin Otte <otte src gnome org>]

commit 0c37c88147433202eec8e61d6c251c98f1ed2e0a
Author: Benjamin Otte <otte redhat com>
Date:   Fri Mar 11 01:27:37 2011 +0100

    gdk: Use CAIRO_OPERATOR_SOURCE when painting double-buffered buffer
    
    Otherwise RGBA surfaces will have issues.
    
    This patch only affects non-implicit paints, ie no paints at all in the
    real world.

 gdk/gdkwindow.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/gdk/gdkwindow.c b/gdk/gdkwindow.c
index 8a5c87d..8318b99 100644
--- a/gdk/gdkwindow.c
+++ b/gdk/gdkwindow.c
@@ -2969,6 +2969,7 @@ gdk_window_end_paint (GdkWindow *window)
       cairo_region_intersect (full_clip, paint->region);
 
       cr = gdk_cairo_create (window);
+      cairo_set_operator (cr, CAIRO_OPERATOR_SOURCE);
       cairo_set_source_surface (cr, paint->surface, 0, 0);
       gdk_cairo_region (cr, full_clip);
       cairo_fill (cr);