[gtk+/layered-windows: 7/10] gdk: Make sure we don't copy to/from layered regions when moving a window

[Alexander Larsson <alexl src gnome org>]

commit 9731db4496bc28ee082269ad0d192267058ad9d1
Author: Alexander Larsson <alexl redhat com>
Date:   Thu Dec 1 16:27:37 2011 +0100

    gdk: Make sure we don't copy to/from layered regions when moving a window

 gdk/gdkwindow.c |   17 +++++++++++++++--
 1 files changed, 15 insertions(+), 2 deletions(-)
---
diff --git a/gdk/gdkwindow.c b/gdk/gdkwindow.c
index 22062a0..f37eb2e 100644
--- a/gdk/gdkwindow.c
+++ b/gdk/gdkwindow.c
@@ -6009,7 +6009,7 @@ gdk_window_move_resize_internal (GdkWindow *window,
 				 gint       width,
 				 gint       height)
 {
-  cairo_region_t *old_region, *new_region, *copy_area;
+  cairo_region_t *old_region, *old_layered, *new_region, *copy_area;
   cairo_region_t *old_native_child_region, *new_native_child_region;
   GdkWindow *impl_window;
   GdkWindowImplClass *impl_class;
@@ -6042,6 +6042,7 @@ gdk_window_move_resize_internal (GdkWindow *window,
 
   expose = FALSE;
   old_region = NULL;
+  old_layered = NULL;
 
   impl_window = gdk_window_get_impl_window (window);
 
@@ -6055,8 +6056,10 @@ gdk_window_move_resize_internal (GdkWindow *window,
       expose = TRUE;
 
       old_region = cairo_region_copy (window->clip_region);
-      /* Adjust region to parent window coords */
+      old_layered = cairo_region_copy (window->layered_region);
+      /* Adjust regions to parent window coords */
       cairo_region_translate (old_region, window->x, window->y);
+      cairo_region_translate (old_layered, window->x, window->y);
 
       old_native_child_region = collect_native_child_region (window, TRUE);
       if (old_native_child_region)
@@ -6138,6 +6141,15 @@ gdk_window_move_resize_internal (GdkWindow *window,
        */
       copy_area = cairo_region_copy (new_region);
 
+      /* Don't copy from a previously layered region */
+      cairo_region_translate (old_layered, dx, dy);
+      cairo_region_subtract (copy_area, old_layered);
+
+      /* Don't copy into a layered region */
+      cairo_region_translate (copy_area, -window->x, -window->y);
+      cairo_region_subtract (copy_area, window->layered_region);
+      cairo_region_translate (copy_area, window->x, window->y);
+
       cairo_region_union (new_region, old_region);
 
       if (old_native_child_region)
@@ -6185,6 +6197,7 @@ gdk_window_move_resize_internal (GdkWindow *window,
       gdk_window_invalidate_region_full (window->parent, new_region, TRUE, CLEAR_BG_ALL);
 
       cairo_region_destroy (old_region);
+      cairo_region_destroy (old_layered);
       cairo_region_destroy (new_region);
     }