[gtk+] Modify window system exposes wrt outstanding moves

[Alexander Larsson <alexl src gnome org>]

commit 8a517dc0bb3299b1d6e9491d1f7e926a47deb305
Author: Alexander Larsson <alexl redhat com>
Date:   Thu Aug 13 13:13:47 2009 +0200

    Modify window system exposes wrt outstanding moves
    
    If there are outstanding moves in an area that intersects
    the source of an outstanding move we need to move the invalid
    area correspondingly, otherwise we will expose the wrong area
    as the outstanding move copy will happen before we expose
    the invalid area.

 gdk/gdkinternals.h |    2 +-
 gdk/gdkwindow.c    |   31 ++++++++++++++++++++++++++++++-
 2 files changed, 31 insertions(+), 2 deletions(-)
---
diff --git a/gdk/gdkinternals.h b/gdk/gdkinternals.h
index 75eb068..a668e68 100644
--- a/gdk/gdkinternals.h
+++ b/gdk/gdkinternals.h
@@ -605,7 +605,7 @@ void _gdk_display_enable_motion_hints     (GdkDisplay *display);
 
 
 void _gdk_window_invalidate_for_expose (GdkWindow       *window,
-					const GdkRegion *region);
+					GdkRegion       *region);
 
 void _gdk_windowing_set_cairo_surface_size (cairo_surface_t *surface,
 					    int width,
diff --git a/gdk/gdkwindow.c b/gdk/gdkwindow.c
index cfb9d9e..04d8010 100644
--- a/gdk/gdkwindow.c
+++ b/gdk/gdkwindow.c
@@ -5300,8 +5300,37 @@ gdk_window_invalidate_region (GdkWindow       *window,
  **/
 void
 _gdk_window_invalidate_for_expose (GdkWindow       *window,
-				   const GdkRegion *region)
+				   GdkRegion       *region)
 {
+  GdkWindowObject *private = (GdkWindowObject *) window;
+  GdkWindowRegionMove *move;
+  GdkRegion *move_region;
+  GList *l;
+
+  /* Any invalidations comming from the windowing system will
+     be in areas that may be moved by outstanding moves,
+     so we need to modify the expose region correspondingly,
+     otherwise we would expose in the wrong place, as the
+     outstanding moves will be copied before we draw the
+     exposes. */
+  for (l = private->outstanding_moves; l != NULL; l = l->next)
+    {
+      move = l->data;
+
+      /* covert to move source region */
+      move_region = gdk_region_copy (move->dest_region);
+      gdk_region_offset (move_region, -move->dx, -move->dy);
+
+      /* Move area of region that intersects with move source
+	 by dx, dy of the move*/
+      gdk_region_intersect (move_region, region);
+      gdk_region_subtract (region, move_region);
+      gdk_region_offset (move_region, move->dx, move->dy);
+      gdk_region_union (region, move_region);
+
+      gdk_region_destroy (move_region);
+    }
+
   gdk_window_invalidate_maybe_recurse (window, region,
 				       (gboolean (*) (GdkWindow *, gpointer))gdk_window_has_no_impl,
 				       NULL);