Make set_cairo_surface_size a vfunc on GdkWindowImpl

Note the special implementation of this method on GdkOffscreenWindow
that makes sure its current surface is not destroyed.

gdk/gdkinternals.h

@@ -495,10 +495,6 @@ void _gdk_display_pointer_info_foreach (GdkDisplay                   *display,
 void _gdk_window_invalidate_for_expose (GdkWindow       *window,
 					cairo_region_t       *region);
 
-gboolean _gdk_windowing_set_cairo_surface_size (cairo_surface_t *surface,
-					        int width,
-					        int height);
-
 GdkWindow * _gdk_window_find_child_at (GdkWindow *window,
 				       int x, int y);
 GdkWindow * _gdk_window_find_descendant_at (GdkWindow *toplevel,

gdk/gdkoffscreenwindow.c

@@ -597,6 +597,18 @@ gdk_offscreen_window_translate (GdkWindow      *window,
   _gdk_window_add_damage (window, area);
 }
 
+static cairo_surface_t *
+gdk_offscreen_window_resize_cairo_surface (GdkWindow       *window,
+                                           cairo_surface_t *surface,
+                                           gint             width,
+                                           gint             height)
+{
+  /* No-op.  The surface gets resized in
+   * gdk_offscreen_window_move_resize_internal().
+   */
+  return surface;
+}
+
 /**
  * gdk_offscreen_window_set_embedder:
  * @window: a #GdkWindow
@@ -700,4 +712,5 @@ gdk_offscreen_window_impl_iface_init (GdkWindowImplIface *iface)
   iface->get_root_coords = gdk_offscreen_window_get_root_coords;
   iface->get_device_state = gdk_offscreen_window_get_device_state;
   iface->destroy = gdk_offscreen_window_destroy;
+  iface->resize_cairo_surface = gdk_offscreen_window_resize_cairo_surface;
 }

gdk/gdkwindow.c

@@ -1018,14 +1018,17 @@ recompute_visible_regions_internal (GdkWindowObject *private,
       recompute_visible_regions_internal (private->parent, TRUE, FALSE, FALSE);
     }
 
-  if (private->cairo_surface &&
-      (!gdk_window_has_impl (private) ||
-       !_gdk_windowing_set_cairo_surface_size (private->cairo_surface,
-                                               private->width,
-                                               private->height)))
+  if (private->cairo_surface && gdk_window_has_impl (private))
     {
-      gdk_window_drop_cairo_surface (private);
+      GdkWindowImplIface *iface = GDK_WINDOW_IMPL_GET_IFACE (private->impl);
+
+      private->cairo_surface = iface->resize_cairo_surface (private->impl,
+                                                            private->cairo_surface,
+                                                            private->width,
+                                                            private->height);
     }
+  else if (private->cairo_surface)
+    gdk_window_drop_cairo_surface (private);
 }
 
 /* Call this when private has changed in one or more of these ways:

gdk/gdkwindowimpl.h

@@ -141,6 +141,11 @@ struct _GdkWindowImplIface
   void         (* destroy)              (GdkWindow       *window,
 					 gboolean         recursing,
 					 gboolean         foreign_destroy);
+
+  cairo_surface_t * (* resize_cairo_surface) (GdkWindow       *window,
+                                              cairo_surface_t *surface,
+                                              gint             width,
+                                              gint             height);
 };
 
 /* Interface Functions */

gdk/quartz/gdkdrawable-quartz.c

@@ -32,15 +32,6 @@ typedef struct {
   CGContextRef  cg_context;
 } GdkQuartzCairoSurfaceData;
 
-gboolean
-_gdk_windowing_set_cairo_surface_size (cairo_surface_t *surface,
-				       int              width,
-				       int              height)
-{
-  /* This is not supported with quartz surfaces. */
-  return FALSE;
-}
-
 static void
 gdk_quartz_cairo_surface_destroy (void *data)
 {

gdk/quartz/gdkwindow-quartz.c

@@ -1086,6 +1086,18 @@ _gdk_quartz_window_destroy (GdkWindow *window,
     }
 }
 
+static cairo_surface_t *
+gdk_window_quartz_resize_cairo_surface (GdkWindow       *window,
+                                        cairo_surface_t *surface,
+                                        gint             width,
+                                        gint             height)
+{
+  /* Quartz surfaces cannot be resized */
+  cairo_surface_destroy (surface);
+
+  return NULL;
+}
+
 void
 _gdk_windowing_window_destroy_foreign (GdkWindow *window)
 {
@@ -2986,6 +2998,7 @@ gdk_window_impl_iface_init (GdkWindowImplIface *iface)
   iface->queue_antiexpose = _gdk_quartz_window_queue_antiexpose;
   iface->translate = _gdk_quartz_window_translate;
   iface->destroy = _gdk_quartz_window_destroy;
+  iface->resize_cairo_surface = gdk_window_quartz_resize_cairo_surface;
 }
 
 

gdk/win32/gdkdrawable-win32.c

@@ -228,15 +228,6 @@ gdk_win32_ref_cairo_surface (GdkDrawable *drawable)
   return impl->cairo_surface;
 }
 
-gboolean
-_gdk_windowing_set_cairo_surface_size (cairo_surface_t *surface,
-				       gint width,
-				       gint height)
-{
-  // Do nothing.  The surface size is determined by the DC
-  return FALSE;
-}
-
 HGDIOBJ
 gdk_win32_drawable_get_handle (GdkDrawable *drawable)
 {

gdk/win32/gdkwindow-win32.c

@@ -744,6 +744,18 @@ _gdk_win32_window_destroy (GdkWindow *window,
   gdk_win32_handle_table_remove (GDK_WINDOW_HWND (window));
 }
 
+static cairo_surface_t *
+gdk_win32_window_resize_cairo_surface (GdkWindow       *window,
+                                       cairo_surface_t *surface,
+                                       gint             width,
+                                       gint             height)
+{
+  /* XXX: Make Cairo surface use DC clip */
+  cairo_surface_destroy (surface);
+
+  return NULL;
+}
+
 void
 _gdk_windowing_window_destroy_foreign (GdkWindow *window)
 {
@@ -3299,6 +3311,7 @@ gdk_window_impl_iface_init (GdkWindowImplIface *iface)
   iface->queue_antiexpose = _gdk_win32_window_queue_antiexpose;
   iface->translate = _gdk_win32_window_translate;
   iface->destroy = _gdk_win32_window_destroy;
+  iface->resize_cairo_surface = gdk_win32_window_resize_cairo_surface;
 }
 
 gboolean

gdk/x11/gdkdrawable-x11.c

@@ -194,15 +194,6 @@ gdk_x11_cairo_surface_destroy (void *data)
   impl->cairo_surface = NULL;
 }
 
-gboolean
-_gdk_windowing_set_cairo_surface_size (cairo_surface_t *surface,
-				       int width,
-				       int height)
-{
-  cairo_xlib_surface_set_size (surface, width, height);
-  return TRUE;
-}
-
 static cairo_surface_t *
 gdk_x11_create_cairo_surface (GdkDrawable *drawable,
 			      int width,

gdk/x11/gdkwindow-x11.c

@@ -1028,6 +1028,17 @@ _gdk_x11_window_destroy (GdkWindow *window,
     }
 }
 
+static cairo_surface_t *
+gdk_window_x11_resize_cairo_surface (GdkWindow       *window,
+                                     cairo_surface_t *surface,
+                                     gint             width,
+                                     gint             height)
+{
+  cairo_xlib_surface_set_size (surface, width, height);
+
+  return surface;
+}
+
 void
 _gdk_windowing_window_destroy_foreign (GdkWindow *window)
 {
@@ -5514,6 +5525,7 @@ gdk_window_impl_iface_init (GdkWindowImplIface *iface)
   iface->queue_antiexpose = _gdk_x11_window_queue_antiexpose;
   iface->translate = _gdk_x11_window_translate;
   iface->destroy = _gdk_x11_window_destroy;
+  iface->resize_cairo_surface = gdk_window_x11_resize_cairo_surface;
 }
 
 static Bool