gdkwindow: Handle updates created by outstanding moves in same update

If gdk_window_flush_outstanding_moves() creates new update area
we handle this directly in the same draw to avoid flashing.

This mainly affects win32 as X11 does its exposes from moves async.
However, its important for win32 since ScrollDC seems to sometimes
invalidate (and not copy) unexected regions.

http://bugzilla.gnome.org/show_bug.cgi?674051

diff --git a/gdk/gdkwindow.c b/gdk/gdkwindow.c
index 482f4990e6bc9170fc912e128d9c3f89ab7aa7f1..3f0a58f4f7041593e6d10ec33e702e91559113a0 100644 (file)
--- a/gdk/gdkwindow.c
+++ b/gdk/gdkwindow.c
@@ -4070,6 +4070,7 @@ gdk_window_process_updates_internal (GdkWindow *window)
   GdkWindowImplClass *impl_class;
   gboolean save_region = FALSE;
   GdkRectangle clip_box;
+  int iteration;
 
   /* Ensure the window lives while updating it */
   g_object_ref (window);
@@ -4077,8 +4078,15 @@ gdk_window_process_updates_internal (GdkWindow *window)
   /* If an update got queued during update processing, we can get a
    * window in the update queue that has an empty update_area.
    * just ignore it.
+   *
+   * We run this multiple times if needed because on win32 the
+   * first run can cause new (synchronous) updates from
+   * gdk_window_flush_outstanding_moves(). However, we
+   * limit it to two iterations to avoid any potential loops.
    */
-  if (window->update_area)
+  iteration = 0;
+  while (window->update_area &&
+        iteration++ < 2)
     {
       cairo_region_t *update_area = window->update_area;
       window->update_area = NULL;