[gtk+/gtk-3-10] gdkcairo: Don't require gtk_init() for set_source_pixbuf()

[Matthias Clasen <matthiasc src gnome org>]

commit 16c8445cc1696430649b580741cf5fc2a7b13a2f
Author: Benjamin Otte <otte redhat com>
Date:   Tue Sep 24 16:37:37 2013 +0200

    gdkcairo: Don't require gtk_init() for set_source_pixbuf()
    
    Instead of using the default display's root window's surface, use the
    target surface of the passed in cairo_t to create the similar image from.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=708547

 gdk/gdkcairo.c |   12 +++++++++++-
 1 files changed, 11 insertions(+), 1 deletions(-)
---
diff --git a/gdk/gdkcairo.c b/gdk/gdkcairo.c
index d16a619..ae0c294 100644
--- a/gdk/gdkcairo.c
+++ b/gdk/gdkcairo.c
@@ -321,9 +321,19 @@ gdk_cairo_set_source_pixbuf (cairo_t         *cr,
                              gdouble          pixbuf_x,
                              gdouble          pixbuf_y)
 {
+  cairo_format_t format;
   cairo_surface_t *surface;
 
-  surface = gdk_cairo_surface_create_from_pixbuf (pixbuf, 1, NULL);
+  if (gdk_pixbuf_get_n_channels (pixbuf) == 3)
+    format = CAIRO_FORMAT_RGB24;
+  else
+    format = CAIRO_FORMAT_ARGB32;
+
+  surface = cairo_surface_create_similar_image (cairo_get_target (cr),
+                                                format,
+                                                gdk_pixbuf_get_width (pixbuf),
+                                                gdk_pixbuf_get_height (pixbuf));
+
   cairo_set_source_surface (cr, surface, pixbuf_x, pixbuf_y);
   cairo_surface_destroy (surface);
 }