Clear background on expose with no EXPOSURE_MASK

Apps that set no exposure mask rely on the system clearing things
to the window background, so we need to do this ourselves.

Also, don't do this on foreign windows, as they are not controlled
by us. In fact don't do exposes on foreign windows either.

diff --git a/gdk/gdkwindow.c b/gdk/gdkwindow.c
index a6e26967be3ac324ab0f91f4adbd8c652976d589..1245e5702f8e097c1b956e8b07fc82c05fc2a1a7 100644 (file)
--- a/gdk/gdkwindow.c
+++ b/gdk/gdkwindow.c
@@ -4443,21 +4443,37 @@ _gdk_window_process_updates_recurse (GdkWindow *window,
       gdk_region_destroy (child_region);
     }
 
-  if (private->event_mask & GDK_EXPOSURE_MASK &&
-      !gdk_region_empty (expose_region))
+  if (!gdk_region_empty (expose_region) &&
+      private->window_type != GDK_WINDOW_FOREIGN)
     {
-      GdkEvent event;
-      
-      event.expose.type = GDK_EXPOSE;
-      event.expose.window = g_object_ref (window);
-      event.expose.send_event = FALSE;
-      event.expose.count = 0;
-      event.expose.region = expose_region;
-      gdk_region_get_clipbox (expose_region, &event.expose.area);
-      
-      (*_gdk_event_func) (&event, _gdk_event_data);
-      
-      g_object_unref (window);
+      if (private->event_mask & GDK_EXPOSURE_MASK)
+       {
+         GdkEvent event;
+         
+         event.expose.type = GDK_EXPOSE;
+         event.expose.window = g_object_ref (window);
+         event.expose.send_event = FALSE;
+         event.expose.count = 0;
+         event.expose.region = expose_region;
+         gdk_region_get_clipbox (expose_region, &event.expose.area);
+         
+         (*_gdk_event_func) (&event, _gdk_event_data);
+         
+         g_object_unref (window);
+       }
+      else
+       {
+         /* No exposure mask set, so nothing will be drawn, the
+          * app relies on the background being what it specified
+          * for the window. So, we need to clear this manually.
+          *
+          * We use begin/end_paint around the clear so that we can
+          * piggyback on the implicit paint */
+         
+         gdk_window_begin_paint_region (window, expose_region);
+         gdk_window_clear_region_internal (window, expose_region, FALSE);
+         gdk_window_end_paint (window);
+       }
     }
 }