gdkframeclock: Loop the layout phase if needed

In the case where the layout phase queued a layout we don't
want to progress to the paint phase with invalid allocations, so
we loop the layout. This shouldn't normally happen, but it may
happen in some edge cases like if user/wm resizes clash with
natural window size changes from a gtk widget. This should not
generally loop though, so we detect this after 4 cycles and
print a warning.

This was detected because of an issue in GtkWindow where it
seems to incorrectly handle the case of a user interactive resize.
It seems gtk_window_move_resize() believes that configure_request_size_changed
changed due to hitting some corner case so it calls
gtk_widget_queue_resize_no_redraw(), marking the window as need_alloc
after the layout phase. This commit fixes the issue, but we should
also look into if we can fix that.

gdk/broadway/gdkwindow-broadway.c

@@ -1470,56 +1470,6 @@ _gdk_broadway_window_queue_antiexpose (GdkWindow *window,
   return TRUE;
 }
 
-static void
-copy_region (cairo_surface_t *surface,
-	     cairo_region_t *area,
-	     gint            dx,
-	     gint            dy)
-{
-  cairo_t *cr;
-
-  cr = cairo_create (surface);
-
-  gdk_cairo_region (cr, area);
-  cairo_clip (cr);
-
-  /* NB: This is a self-copy and Cairo doesn't support that yet.
-   * So we do a litle trick.
-   */
-  cairo_push_group (cr);
-
-  cairo_set_source_surface (cr, surface, dx, dy);
-  cairo_paint (cr);
-
-  cairo_pop_group_to_source (cr);
-  cairo_paint (cr);
-
-  cairo_destroy (cr);
-}
-
-void
-_gdk_broadway_window_translate (GdkWindow      *window,
-				cairo_region_t *area,
-				gint            dx,
-				gint            dy)
-{
-  GdkWindowImplBroadway *impl;
-  GdkBroadwayDisplay *broadway_display;
-
-  impl = GDK_WINDOW_IMPL_BROADWAY (window->impl);
-
-  if (impl->surface)
-    {
-      copy_region (impl->surface, area, dx, dy);
-      broadway_display = GDK_BROADWAY_DISPLAY (gdk_window_get_display (window));
-
-      if (_gdk_broadway_server_window_translate (broadway_display->server,
-						 impl->id,
-						 area, dx, dy))
-	queue_flush (window);
-    }
-}
-
 guint32
 gdk_broadway_get_last_seen_time (GdkWindow  *window)
 {
@@ -1558,7 +1508,6 @@ gdk_window_impl_broadway_class_init (GdkWindowImplBroadwayClass *klass)
   impl_class->input_shape_combine_region = gdk_window_broadway_input_shape_combine_region;
   impl_class->set_static_gravities = gdk_window_broadway_set_static_gravities;
   impl_class->queue_antiexpose = _gdk_broadway_window_queue_antiexpose;
-  impl_class->translate = _gdk_broadway_window_translate;
   impl_class->destroy = _gdk_broadway_window_destroy;
   impl_class->destroy_foreign = gdk_broadway_window_destroy_foreign;
   impl_class->resize_cairo_surface = gdk_window_broadway_resize_cairo_surface;

gdk/gdkframeclockidle.c

@@ -384,6 +384,7 @@ gdk_frame_clock_paint_idle (void *data)
         case GDK_FRAME_CLOCK_PHASE_LAYOUT:
           if (priv->freeze_count == 0)
             {
+	      int iter;
 #ifdef G_ENABLE_DEBUG
               if ((_gdk_debug_flags & GDK_DEBUG_FRAMES) != 0)
                 {
@@ -394,11 +395,20 @@ gdk_frame_clock_paint_idle (void *data)
 #endif /* G_ENABLE_DEBUG */
 
               priv->phase = GDK_FRAME_CLOCK_PHASE_LAYOUT;
-              if (priv->requested & GDK_FRAME_CLOCK_PHASE_LAYOUT)
+	      /* We loop in the layout phase, because we don't want to progress
+	       * into the paint phase with invalid size allocations. This may
+	       * happen in some situation like races between user window
+	       * resizes and natural size changes.
+	       */
+	      iter = 0;
+              while ((priv->requested & GDK_FRAME_CLOCK_PHASE_LAYOUT) &&
+		     priv->freeze_count == 0 && iter++ < 4)
                 {
                   priv->requested &= ~GDK_FRAME_CLOCK_PHASE_LAYOUT;
                   g_signal_emit_by_name (G_OBJECT (clock), "layout");
                 }
+	      if (iter == 4)
+		g_warning ("gdk-frame-clock: layout continuously requested, giving up after 4 tries");
             }
         case GDK_FRAME_CLOCK_PHASE_PAINT:
           if (priv->freeze_count == 0)

gdk/gdkinternals.h

@@ -224,6 +224,7 @@ struct _GdkWindow
   guint native_visibility : 2; /* the native visibility of a impl windows */
   guint viewable : 1; /* mapped and all parents mapped */
   guint applied_shape : 1;
+  guint in_update : 1;
   GdkFullscreenMode fullscreen_mode;
 
   /* The GdkWindow that has the impl, ref:ed if another window.
@@ -250,10 +251,6 @@ struct _GdkWindow
   GdkCursor *cursor;
   GHashTable *device_cursor;
 
-  GSList *implicit_paint;
-
-  GList *outstanding_moves;
-
   cairo_region_t *shape;
   cairo_region_t *input_shape;
 
@@ -269,6 +266,7 @@ struct _GdkWindow
   guint num_offscreen_children;
 
   GdkFrameClock *frame_clock; /* NULL to use from parent or default */
+  GdkWindowInvalidateHandlerFunc invalidate_handler;
 };
 
 #define GDK_WINDOW_TYPE(d) (((GDK_WINDOW (d)))->window_type)

gdk/gdkoffscreenwindow.c

@@ -555,42 +555,6 @@ gdk_offscreen_window_queue_antiexpose (GdkWindow *window,
   return FALSE;
 }
 
-static void
-gdk_offscreen_window_translate (GdkWindow      *window,
-                                cairo_region_t *area,
-                                gint            dx,
-                                gint            dy)
-{
-  GdkOffscreenWindow *offscreen = GDK_OFFSCREEN_WINDOW (window->impl);
-
-  if (offscreen->surface)
-    {
-      cairo_t *cr;
-
-      cr = cairo_create (offscreen->surface);
-
-      area = cairo_region_copy (area);
-
-      gdk_cairo_region (cr, area);
-      cairo_clip (cr);
-
-      /* NB: This is a self-copy and Cairo doesn't support that yet.
-       * So we do a litle trick.
-       */
-      cairo_push_group (cr);
-
-      cairo_set_source_surface (cr, offscreen->surface, dx, dy);
-      cairo_paint (cr);
-
-      cairo_pop_group_to_source (cr);
-      cairo_paint (cr);
-
-      cairo_destroy (cr);
-    }
-
-  _gdk_window_add_damage (window, area);
-}
-
 static cairo_surface_t *
 gdk_offscreen_window_resize_cairo_surface (GdkWindow       *window,
                                            cairo_surface_t *surface,
@@ -752,7 +716,6 @@ gdk_offscreen_window_class_init (GdkOffscreenWindowClass *klass)
   impl_class->input_shape_combine_region = gdk_offscreen_window_input_shape_combine_region;
   impl_class->set_static_gravities = gdk_offscreen_window_set_static_gravities;
   impl_class->queue_antiexpose = gdk_offscreen_window_queue_antiexpose;
-  impl_class->translate = gdk_offscreen_window_translate;
   impl_class->destroy = gdk_offscreen_window_destroy;
   impl_class->destroy_foreign = NULL;
   impl_class->resize_cairo_surface = gdk_offscreen_window_resize_cairo_surface;

gdk/gdkwindow.h

@@ -634,6 +634,26 @@ gboolean gdk_window_set_static_gravities (GdkWindow *window,
 
 /* GdkWindow */
 
+/**
+ * GdkWindowInvalidateHandlerFunc:
+ * @window: a #GdkWindow
+ * @region: a #cairo_region_t
+ *
+ * Whenever some area of the window is invalidated (directly in the
+ * window or in a child window) this gets called with @region in
+ * the coordinate space of @window. You can use @region to just
+ * keep track of the dirty region, or you can actually change
+ * @region in case you are doing display tricks like showing
+ * a child in multiple places.
+ *
+ * Since: 3.10
+ */
+typedef void (*GdkWindowInvalidateHandlerFunc)  (GdkWindow *window,
+						 cairo_region_t *region);
+GDK_AVAILABLE_IN_3_10
+void gdk_window_set_invalidate_handler (GdkWindow *window,
+					GdkWindowInvalidateHandlerFunc handler);
+
 gboolean      gdk_window_has_native         (GdkWindow       *window);
 void              gdk_window_set_type_hint (GdkWindow        *window,
                                             GdkWindowTypeHint hint);

gdk/gdkwindowimpl.h

@@ -125,16 +125,6 @@ struct _GdkWindowImplClass
   gboolean     (* queue_antiexpose)     (GdkWindow       *window,
 					 cairo_region_t  *update_area);
 
-  /* Called to move @area inside @window by @dx x @dy pixels. @area is 
-   * guaranteed to be inside @window. If part of @area is not invisible or
-   * invalid, it is this function's job to queue expose events in those 
-   * areas.
-   */
-  void         (* translate)            (GdkWindow       *window,
-					 cairo_region_t  *area,
-					 gint            dx,
-					 gint            dy);
-
 /* Called to do the windowing system specific part of gdk_window_destroy(),
  *
  * window: The window being destroyed

gdk/quartz/gdkwindow-quartz.c

@@ -2237,49 +2237,6 @@ gdk_quartz_window_queue_antiexpose (GdkWindow *window,
   return FALSE;
 }
 
-static void
-gdk_quartz_window_translate (GdkWindow      *window,
-                             cairo_region_t *area,
-                             gint            dx,
-                             gint            dy)
-{
-  cairo_region_t *invalidate, *scrolled;
-  GdkWindowImplQuartz *impl = (GdkWindowImplQuartz *)window->impl;
-  GdkRectangle extents;
-
-  cairo_region_get_extents (area, &extents);
-
-  [impl->view scrollRect:NSMakeRect (extents.x - dx, extents.y - dy,
-                                     extents.width, extents.height)
-              by:NSMakeSize (dx, dy)];
-
-  if (impl->needs_display_region)
-    {
-      cairo_region_t *intersection;
-
-      /* Invalidate already invalidated area that was moved at new
-       * location.
-       */
-      intersection = cairo_region_copy (impl->needs_display_region);
-      cairo_region_intersect (intersection, area);
-      cairo_region_translate (intersection, dx, dy);
-
-      gdk_quartz_window_set_needs_display_in_region (window, intersection);
-      cairo_region_destroy (intersection);
-    }
-
-  /* Calculate newly exposed area that needs invalidation */
-  scrolled = cairo_region_copy (area);
-  cairo_region_translate (scrolled, dx, dy);
-
-  invalidate = cairo_region_copy (area);
-  cairo_region_subtract (invalidate, scrolled);
-  cairo_region_destroy (scrolled);
-
-  gdk_quartz_window_set_needs_display_in_region (window, invalidate);
-  cairo_region_destroy (invalidate);
-}
-
 static void
 gdk_quartz_window_set_focus_on_map (GdkWindow *window,
                                     gboolean focus_on_map)
@@ -3078,7 +3035,6 @@ gdk_window_impl_quartz_class_init (GdkWindowImplQuartzClass *klass)
   impl_class->input_shape_combine_region = gdk_window_quartz_input_shape_combine_region;
   impl_class->set_static_gravities = gdk_window_quartz_set_static_gravities;
   impl_class->queue_antiexpose = gdk_quartz_window_queue_antiexpose;
-  impl_class->translate = gdk_quartz_window_translate;
   impl_class->destroy = gdk_quartz_window_destroy;
   impl_class->destroy_foreign = gdk_quartz_window_destroy_foreign;
   impl_class->resize_cairo_surface = gdk_window_quartz_resize_cairo_surface;

gdk/wayland/gdkwindow-wayland.c

@@ -1009,15 +1009,6 @@ gdk_wayland_window_queue_antiexpose (GdkWindow *window,
   return FALSE;
 }
 
-static void
-gdk_wayland_window_translate (GdkWindow      *window,
-			      cairo_region_t *area,
-			      gint            dx,
-			      gint            dy)
-{
-  _gdk_window_invalidate_for_expose (window, area);
-}
-
 static void
 gdk_wayland_window_destroy (GdkWindow *window,
 			    gboolean   recursing,
@@ -1726,7 +1717,6 @@ _gdk_window_impl_wayland_class_init (GdkWindowImplWaylandClass *klass)
   impl_class->input_shape_combine_region = gdk_window_wayland_input_shape_combine_region;
   impl_class->set_static_gravities = gdk_window_wayland_set_static_gravities;
   impl_class->queue_antiexpose = gdk_wayland_window_queue_antiexpose;
-  impl_class->translate = gdk_wayland_window_translate;
   impl_class->destroy = gdk_wayland_window_destroy;
   impl_class->destroy_foreign = gdk_window_wayland_destroy_foreign;
   impl_class->resize_cairo_surface = gdk_window_wayland_resize_cairo_surface;

gdk/win32/gdkwindow-win32.c

@@ -3319,77 +3319,6 @@ _gdk_win32_window_queue_antiexpose (GdkWindow *window,
   return FALSE;
 }
 
-/* Gets called from gdwindow.c(do_move_region_bits_on_impl)
- * and got tested with testgtk::big_window. Given the previous,
- * untested implementation this one looks much too simple ;)
- */
-static void
-_gdk_win32_window_translate (GdkWindow *window,
-                             cairo_region_t *area, /* In impl window coords */
-                             gint       dx,
-                             gint       dy)
-{
-  GdkWindowImplWin32 *impl = GDK_WINDOW_IMPL_WIN32 (window->impl);
-  HRGN hrgn, area_hrgn;
-  cairo_region_t *update_region;
-  HDC hdc;
-  int ret;
-
-  /* Note: This is the destination area, not the source, and
-     it has been moved by dx, dy from the source area */
-  area_hrgn = cairo_region_to_hrgn (area, 0, 0);
-
-  /* First we copy any outstanding invalid areas in the 
-     source area to the new position in the destination area */
-  hrgn = CreateRectRgn (0, 0, 0, 0);
-  ret = GetUpdateRgn (GDK_WINDOW_HWND (window), hrgn, FALSE);
-  if (ret == ERROR)
-    WIN32_API_FAILED ("GetUpdateRgn");
-  else if (ret != NULLREGION)
-    {
-      /* Convert the source invalid region as it would be copied */
-      OffsetRgn (hrgn, dx, dy);
-      /* Keep what intersects the copy destination area */
-      ret = CombineRgn (hrgn, hrgn, area_hrgn, RGN_AND);
-      /* And invalidate it */
-      if (ret == ERROR)
-        WIN32_API_FAILED ("CombineRgn");
-      else if (ret != NULLREGION)
-	API_CALL (InvalidateRgn, (GDK_WINDOW_HWND (window), hrgn, TRUE));
-    }
-
-  /* Then we copy the bits, invalidating whatever is copied from
-     otherwise invisible areas */
-
-  hdc = _gdk_win32_impl_acquire_dc (impl);
-
-  /* Clip hdc to target region */
-  API_CALL (SelectClipRgn, (hdc, area_hrgn));
-
-  SetRectRgn (hrgn, 0, 0, 0, 0);
-
-  if (!ScrollDC (hdc, dx, dy, NULL, NULL, hrgn, NULL))
-    WIN32_GDI_FAILED ("ScrollDC");
-  else
-    {
-      update_region = _gdk_win32_hrgn_to_region (hrgn);
-      if (!cairo_region_is_empty (update_region))
-	_gdk_window_invalidate_for_expose (window, update_region);
-      cairo_region_destroy (update_region);
-    }
-
-  /* Unset hdc clip region */
-  API_CALL (SelectClipRgn, (hdc, NULL));
-
-  _gdk_win32_impl_release_dc (impl);
-
-  if (!DeleteObject (hrgn))
-    WIN32_GDI_FAILED ("DeleteObject");
-
-  if (!DeleteObject (area_hrgn))
-    WIN32_GDI_FAILED ("DeleteObject");
-}
-
 static void
 gdk_win32_input_shape_combine_region (GdkWindow *window,
 				      const cairo_region_t *shape_region,
@@ -3556,7 +3485,6 @@ gdk_window_impl_win32_class_init (GdkWindowImplWin32Class *klass)
   impl_class->input_shape_combine_region = gdk_win32_input_shape_combine_region;
   impl_class->set_static_gravities = gdk_win32_window_set_static_gravities;
   impl_class->queue_antiexpose = _gdk_win32_window_queue_antiexpose;
-  impl_class->translate = _gdk_win32_window_translate;
   impl_class->destroy = gdk_win32_window_destroy;
   impl_class->destroy_foreign = gdk_win32_window_destroy_foreign;
   impl_class->resize_cairo_surface = gdk_win32_window_resize_cairo_surface;

gdk/x11/gdkgeometry-x11.c

@@ -28,26 +28,11 @@
 typedef struct _GdkWindowQueueItem GdkWindowQueueItem;
 typedef struct _GdkWindowParentPos GdkWindowParentPos;
 
-typedef enum {
-  GDK_WINDOW_QUEUE_TRANSLATE,
-  GDK_WINDOW_QUEUE_ANTIEXPOSE
-} GdkWindowQueueType;
-
 struct _GdkWindowQueueItem
 {
   GdkWindow *window;
   gulong serial;
-  GdkWindowQueueType type;
-  union {
-    struct {
-      cairo_region_t *area;
-      gint dx;
-      gint dy;
-    } translate;
-    struct {
-      cairo_region_t *area;
-    } antiexpose;
-  } u;
+  cairo_region_t *antiexpose_area;
 };
 
 void
@@ -140,14 +125,7 @@ queue_item_free (GdkWindowQueueItem *item)
 				    (gpointer *)&(item->window));
     }
   
-  if (item->type == GDK_WINDOW_QUEUE_ANTIEXPOSE)
-    cairo_region_destroy (item->u.antiexpose.area);
-  else
-    {
-      if (item->u.translate.area)
-	cairo_region_destroy (item->u.translate.area);
-    }
-  
+  cairo_region_destroy (item->antiexpose_area);
   g_free (item);
 }
 
@@ -213,11 +191,8 @@ gdk_window_queue (GdkWindow          *window,
 	  GdkWindowQueueItem *item = tmp_list->data;
 	  GList *next = tmp_list->next;
 	  
-	  if (item->type == GDK_WINDOW_QUEUE_ANTIEXPOSE)
-	    {
-	      queue_delete_link (display_x11->translate_queue, tmp_list);
-	      queue_item_free (item);
-	    }
+	  queue_delete_link (display_x11->translate_queue, tmp_list);
+	  queue_item_free (item);
 
 	  tmp_list = next;
 	}
@@ -232,86 +207,12 @@ gdk_window_queue (GdkWindow          *window,
   g_queue_push_tail (display_x11->translate_queue, item);
 }
 
-static GC
-_get_scratch_gc (GdkWindow *window, cairo_region_t *clip_region)
-{
-  GdkX11Screen *screen;
-  XRectangle *rectangles;
-  gint n_rects;
-  gint depth;
-
-  screen = GDK_X11_SCREEN (gdk_window_get_screen (window));
-  depth = gdk_visual_get_depth (gdk_window_get_visual (window)) - 1;
-
-  if (!screen->subwindow_gcs[depth])
-    {
-      XGCValues values;
-      
-      values.graphics_exposures = True;
-      values.subwindow_mode = IncludeInferiors;
-      
-      screen->subwindow_gcs[depth] = XCreateGC (screen->xdisplay,
-                                                GDK_WINDOW_XID (window),
-                                                GCSubwindowMode | GCGraphicsExposures,
-                                                &values);
-    }
-  
-  _gdk_x11_region_get_xrectangles (clip_region,
-                                   0, 0,
-                                   &rectangles,
-                                   &n_rects);
-  
-  XSetClipRectangles (screen->xdisplay,
-                      screen->subwindow_gcs[depth],
-                      0, 0,
-                      rectangles, n_rects,
-                      YXBanded);
-  
-  g_free (rectangles);
-  return screen->subwindow_gcs[depth];
-}
-
-
-
-void
-_gdk_x11_window_translate (GdkWindow      *window,
-                           cairo_region_t *area,
-                           gint            dx,
-                           gint            dy)
-{
-  GdkWindowQueueItem *item;
-  GC xgc;
-  GdkRectangle extents;
-
-  cairo_region_get_extents (area, &extents);
-
-  xgc = _get_scratch_gc (window, area);
-
-  cairo_region_translate (area, -dx, -dy); /* Move to source region */
-
-  item = g_new (GdkWindowQueueItem, 1);
-  item->type = GDK_WINDOW_QUEUE_TRANSLATE;
-  item->u.translate.area = cairo_region_copy (area);
-  item->u.translate.dx = dx;
-  item->u.translate.dy = dy;
-  gdk_window_queue (window, item);
-
-  XCopyArea (GDK_WINDOW_XDISPLAY (window),
-             GDK_WINDOW_XID (window),
-             GDK_WINDOW_XID (window),
-             xgc,
-             extents.x - dx, extents.y - dy,
-             extents.width, extents.height,
-             extents.x, extents.y);
-}
-
 gboolean
 _gdk_x11_window_queue_antiexpose (GdkWindow *window,
 				  cairo_region_t *area)
 {
   GdkWindowQueueItem *item = g_new (GdkWindowQueueItem, 1);
-  item->type = GDK_WINDOW_QUEUE_ANTIEXPOSE;
-  item->u.antiexpose.area = area;
+  item->antiexpose_area = area;
 
   gdk_window_queue (window, item);
 
@@ -339,28 +240,7 @@ _gdk_x11_window_process_expose (GdkWindow    *window,
           if (serial - item->serial > (gulong) G_MAXLONG)
             {
               if (item->window == window)
-                {
-                  if (item->type == GDK_WINDOW_QUEUE_TRANSLATE)
-                    {
-                      if (item->u.translate.area)
-                        {
-                          cairo_region_t *intersection;
-
-                          intersection = cairo_region_copy (invalidate_region);
-                          cairo_region_intersect (intersection, item->u.translate.area);
-                          cairo_region_subtract (invalidate_region, intersection);
-                          cairo_region_translate (intersection, item->u.translate.dx, item->u.translate.dy);
-                          cairo_region_union (invalidate_region, intersection);
-                          cairo_region_destroy (intersection);
-                        }
-                      else
-                        cairo_region_translate (invalidate_region, item->u.translate.dx, item->u.translate.dy);
-                    }
-                  else /* anti-expose */
-                    {
-                      cairo_region_subtract (invalidate_region, item->u.antiexpose.area);
-                    }
-                }
+		cairo_region_subtract (invalidate_region, item->antiexpose_area);
             }
           else
             {

gdk/x11/gdkwindow-x11.c

@@ -5334,7 +5334,6 @@ gdk_window_impl_x11_class_init (GdkWindowImplX11Class *klass)
   impl_class->input_shape_combine_region = gdk_window_x11_input_shape_combine_region;
   impl_class->set_static_gravities = gdk_window_x11_set_static_gravities;
   impl_class->queue_antiexpose = _gdk_x11_window_queue_antiexpose;
-  impl_class->translate = _gdk_x11_window_translate;
   impl_class->destroy = gdk_x11_window_destroy;
   impl_class->destroy_foreign = gdk_x11_window_destroy_foreign;
   impl_class->resize_cairo_surface = gdk_window_x11_resize_cairo_surface;

gtk/gtkcontainer.c

@@ -3365,7 +3365,7 @@ gtk_container_propagate_draw (GtkContainer   *container,
 {
   GdkEventExpose *event;
   GtkAllocation allocation;
-  GdkWindow *window, *w;
+  GdkWindow *window, *w, *event_window, *child_in_window;
   int x, y;
 
   g_return_if_fail (GTK_IS_CONTAINER (container));
@@ -3374,13 +3374,26 @@ gtk_container_propagate_draw (GtkContainer   *container,
 
   g_assert (gtk_widget_get_parent (child) == GTK_WIDGET (container));
 
+  if (!gtk_widget_is_drawable (child))
+    return;
+
+  /* Only propagate to native child window if we're not handling
+     an expose (i.e. in a pure gtk_widget_draw() call */
   event = _gtk_cairo_get_event (cr);
-  if (event)
-    {
-      if (gtk_widget_get_has_window (child) ||
-          gtk_widget_get_window (child) != event->window)
-        return;
-    }
+  if (event &&
+      (gtk_widget_get_has_window (child) &&
+       gdk_window_has_native (gtk_widget_get_window (child))))
+    return;
+
+  /* Never propagate to a child window when exposing a window
+     that is not the one the child widget is in. */
+  event_window = _gtk_cairo_get_event_window (cr);
+  if (gtk_widget_get_has_window (child))
+    child_in_window = gdk_window_get_parent (gtk_widget_get_window (child));
+  else
+    child_in_window = gtk_widget_get_window (child);
+  if (child_in_window != event_window)
+    return;
 
   cairo_save (cr);
 
@@ -3422,7 +3435,7 @@ gtk_container_propagate_draw (GtkContainer   *container,
 
   cairo_translate (cr, x, y);
 
-  _gtk_widget_draw_internal (child, cr, TRUE);
+  gtk_widget_draw (child, cr);
 
   cairo_restore (cr);
 }

gtk/gtkmain.c

@@ -1615,9 +1615,17 @@ gtk_main_do_event (GdkEvent *event)
     case GDK_EXPOSE:
       if (event->any.window && gtk_widget_get_double_buffered (event_widget))
         {
-          gdk_window_begin_paint_region (event->any.window, event->expose.region);
-          gtk_widget_send_expose (event_widget, event);
-          gdk_window_end_paint (event->any.window);
+	  /* We handle exposes only on native windows, relying on the
+	   * draw() handler to propagate down to non-native windows.
+	   * This is ok now that we child windows always are considered
+	   * (semi)transparent.
+	   */
+	  if (gdk_window_has_native (event->expose.window))
+	    {
+	      gdk_window_begin_paint_region (event->any.window, event->expose.region);
+	      gtk_widget_send_expose (event_widget, event);
+	      gdk_window_end_paint (event->any.window);
+	    }
         }
       else
         {

gtk/gtkviewport.c

@@ -66,6 +66,13 @@ struct _GtkViewportPrivate
   GdkWindow      *bin_window;
   GdkWindow      *view_window;
 
+  int backing_surface_x;
+  int backing_surface_y;
+  int backing_surface_w;
+  int backing_surface_h;
+  cairo_surface_t *backing_surface;
+  cairo_region_t *backing_surface_dirty;
+
   /* GtkScrollablePolicy needs to be checked when
    * driving the scrollable adjustment values */
   guint hscroll_policy : 1;
@@ -649,6 +656,37 @@ gtk_viewport_get_view_window (GtkViewport *viewport)
   return viewport->priv->view_window;
 }
 
+static void
+gtk_viewport_bin_window_invalidate_handler (GdkWindow *window,
+					    cairo_region_t *region)
+{
+  gpointer widget;
+  GtkViewport *viewport;
+  GtkViewportPrivate *priv;
+  cairo_rectangle_int_t r;
+
+  gdk_window_get_user_data (window, &widget);
+  viewport = GTK_VIEWPORT (widget);
+  priv = viewport->priv;
+
+  if (priv->backing_surface_dirty == NULL)
+    priv->backing_surface_dirty = cairo_region_create ();
+
+  cairo_region_translate (region,
+			  -priv->backing_surface_x,
+			  -priv->backing_surface_y);
+  cairo_region_union (priv->backing_surface_dirty, region);
+  cairo_region_translate (region,
+			  priv->backing_surface_x,
+			  priv->backing_surface_y);
+
+  r.x = 0;
+  r.y = 0;
+  r.width = priv->backing_surface_w;
+  r.height = priv->backing_surface_h;
+  cairo_region_intersect_rectangle (priv->backing_surface_dirty, &r);
+}
+
 static void
 gtk_viewport_realize (GtkWidget *widget)
 {
@@ -713,6 +751,8 @@ gtk_viewport_realize (GtkWidget *widget)
 
   priv->bin_window = gdk_window_new (priv->view_window, &attributes, attributes_mask);
   gtk_widget_register_window (widget, priv->bin_window);
+  gdk_window_set_invalidate_handler (priv->bin_window,
+				     gtk_viewport_bin_window_invalidate_handler);
 
   child = gtk_bin_get_child (bin);
   if (child)
@@ -750,7 +790,10 @@ gtk_viewport_draw (GtkWidget *widget,
   GtkViewport *viewport = GTK_VIEWPORT (widget);
   GtkViewportPrivate *priv = viewport->priv;
   GtkStyleContext *context;
-  int x, y;
+  cairo_t *backing_cr;
+  GtkWidget *child;
+  int x, y, bin_x, bin_y, new_surf_x, new_surf_y;
+  cairo_rectangle_int_t view_pos;
 
   context = gtk_widget_get_style_context (widget);
 
@@ -766,30 +809,151 @@ gtk_viewport_draw (GtkWidget *widget,
 
       gtk_style_context_restore (context);
     }
-  
-  if (gtk_cairo_should_draw_window (cr, priv->view_window))
+
+  if (priv->backing_surface &&
+      /* Don't use backing surface if rendering elsewhere */
+      cairo_surface_get_type (priv->backing_surface) == cairo_surface_get_type (cairo_get_target (cr)))
     {
-      /* This is a cute hack to ensure the contents of bin_window are
-       * restricted to where they are visible. We only need to do this
-       * clipping when called via gtk_widget_draw() and not in expose
-       * events. And when that happens every window (including this one)
-       * should be drawn.
-       */
-      gdk_window_get_position (priv->view_window, &x, &y);
-      cairo_rectangle (cr, x, y, 
-                       gdk_window_get_width (priv->view_window),
-                       gdk_window_get_height (priv->view_window));
-      cairo_clip (cr);
+      gdk_window_get_position (priv->bin_window, &bin_x, &bin_y);
+      view_pos.x = -bin_x;
+      view_pos.y = -bin_y;
+      view_pos.width = gdk_window_get_width (priv->view_window);
+      view_pos.height = gdk_window_get_height (priv->view_window);
+
+      /* Reposition so all is visible visible */
+      if (priv->backing_surface)
+	{
+	  cairo_rectangle_int_t r;
+	  cairo_region_t *copy_region;
+	  if (view_pos.x < priv->backing_surface_x ||
+	      view_pos.x + view_pos.width >
+	      priv->backing_surface_x + priv->backing_surface_w ||
+	      view_pos.y < priv->backing_surface_y ||
+	      view_pos.y + view_pos.height >
+	      priv->backing_surface_y + priv->backing_surface_h)
+	    {
+	      new_surf_x = priv->backing_surface_x;
+	      if (view_pos.x < priv->backing_surface_x)
+		new_surf_x = view_pos.x - (priv->backing_surface_w - view_pos.width);
+	      else if (view_pos.x + view_pos.width >
+		       priv->backing_surface_x + priv->backing_surface_w)
+		new_surf_x = view_pos.x;
+
+	      new_surf_y = priv->backing_surface_y;
+	      if (view_pos.y < priv->backing_surface_y)
+		new_surf_y = view_pos.y - (priv->backing_surface_h - view_pos.height);
+	      else if (view_pos.y + view_pos.height >
+		       priv->backing_surface_y + priv->backing_surface_h)
+		new_surf_y = view_pos.y;
+
+	      r.x = 0;
+	      r.y = 0;
+	      r.width = priv->backing_surface_w;
+	      r.height = priv->backing_surface_h;
+	      copy_region = cairo_region_create_rectangle (&r);
+
+	      if (priv->backing_surface_dirty)
+		{
+		  cairo_region_subtract (copy_region, priv->backing_surface_dirty);
+		  cairo_region_destroy (priv->backing_surface_dirty);
+		  priv->backing_surface_dirty = NULL;
+		}
+
+	      cairo_region_translate (copy_region,
+				      priv->backing_surface_x - new_surf_x,
+				      priv->backing_surface_y - new_surf_y);
+	      cairo_region_intersect_rectangle (copy_region, &r);
+
+	      backing_cr = cairo_create (priv->backing_surface);
+	      gdk_cairo_region (backing_cr, copy_region);
+	      cairo_clip (backing_cr);
+	      cairo_push_group (backing_cr);
+	      cairo_set_source_surface (backing_cr, priv->backing_surface,
+					priv->backing_surface_x - new_surf_x,
+					priv->backing_surface_y - new_surf_y);
+	      cairo_paint (backing_cr);
+	      cairo_pop_group_to_source (backing_cr);
+	      cairo_set_operator (backing_cr, CAIRO_OPERATOR_SOURCE);
+	      cairo_paint (backing_cr);
+	      cairo_destroy (backing_cr);
+
+	      priv->backing_surface_x = new_surf_x;
+	      priv->backing_surface_y = new_surf_y;
+
+	      cairo_region_xor_rectangle (copy_region, &r);
+	      priv->backing_surface_dirty = copy_region;
+	    }
+	}
+
+      if (priv->backing_surface_dirty &&
+	  !cairo_region_is_empty (priv->backing_surface_dirty))
+	{
+	  backing_cr = cairo_create (priv->backing_surface);
+	  gdk_cairo_region (backing_cr, priv->backing_surface_dirty);
+	  cairo_clip (backing_cr);
+	  cairo_translate (backing_cr,
+			   -priv->backing_surface_x,
+			   -priv->backing_surface_y);
+	  cairo_set_source_rgba (backing_cr,
+				 0, 0, 0, 0);
+	  cairo_set_operator (backing_cr, CAIRO_OPERATOR_SOURCE);
+	  cairo_paint (backing_cr);
+	  cairo_set_operator (backing_cr, CAIRO_OPERATOR_OVER);
+	  gtk_render_background (context, backing_cr,
+				 0,0,
+				 gdk_window_get_width (priv->bin_window),
+				 gdk_window_get_height (priv->bin_window));
+	  child = gtk_bin_get_child (GTK_BIN (widget));
+	  if (child && gtk_widget_get_visible (child)) {
+	    if (!gtk_widget_get_has_window (child))
+	      {
+		GtkAllocation child_allocation;
+		gtk_widget_get_allocation (child, &child_allocation);
+		cairo_translate (backing_cr,
+				 child_allocation.x,
+				 child_allocation.y);
+	      }
+
+	    gtk_widget_draw (child, backing_cr);
+	  }
+
+	  cairo_destroy (backing_cr);
+	}
+
+      if (priv->backing_surface_dirty)
+	{
+	  cairo_region_destroy (priv->backing_surface_dirty);
+	  priv->backing_surface_dirty = NULL;
+	}
+
+      if (gtk_cairo_should_draw_window (cr, priv->bin_window))
+	{
+	  gdk_window_get_position (priv->view_window, &x, &y);
+	  cairo_set_source_surface (cr, priv->backing_surface,
+				    priv->backing_surface_x + bin_x + x,
+				    priv->backing_surface_y + bin_y + y);
+	  cairo_rectangle (cr, x, y,
+			   gdk_window_get_width (priv->view_window),
+			   gdk_window_get_height (priv->view_window));
+	  cairo_fill (cr);
+	}
     }
-
-  if (gtk_cairo_should_draw_window (cr, priv->bin_window))
+  else
     {
-      gdk_window_get_position (priv->bin_window, &x, &y);
-      gtk_render_background (context, cr, x, y,
-                             gdk_window_get_width (priv->bin_window),
-                             gdk_window_get_height (priv->bin_window));
-
-      GTK_WIDGET_CLASS (gtk_viewport_parent_class)->draw (widget, cr);
+      /* Don't use backing_surface */
+      if (gtk_cairo_should_draw_window (cr, priv->bin_window))
+	{
+	  gdk_window_get_position (priv->view_window, &x, &y);
+	  cairo_rectangle (cr, x, y,
+			   gdk_window_get_width (priv->view_window),
+			   gdk_window_get_height (priv->view_window));
+	  cairo_clip (cr);
+	  gdk_window_get_position (priv->bin_window, &x, &y);
+	  gtk_render_background (context, cr, x, y,
+				 gdk_window_get_width (priv->bin_window),
+				 gdk_window_get_height (priv->bin_window));
+	  GTK_WIDGET_CLASS (gtk_viewport_parent_class)->draw (widget, cr);
+	}
     }
 
   return FALSE;
@@ -823,6 +987,7 @@ gtk_viewport_size_allocate (GtkWidget     *widget,
   GtkAdjustment *vadjustment = priv->vadjustment;
   GtkAllocation child_allocation;
   GtkWidget *child;
+  int surface_w, surface_h;
 
   border_width = gtk_container_get_border_width (GTK_CONTAINER (widget));
 
@@ -843,7 +1008,7 @@ gtk_viewport_size_allocate (GtkWidget     *widget,
 
   viewport_set_hadjustment_values (viewport);
   viewport_set_vadjustment_values (viewport);
-  
+
   child_allocation.x = 0;
   child_allocation.y = 0;
   child_allocation.width = gtk_adjustment_get_upper (hadjustment);
@@ -851,6 +1016,7 @@ gtk_viewport_size_allocate (GtkWidget     *widget,
   if (gtk_widget_get_realized (widget))
     {
       GtkAllocation view_allocation;
+      cairo_rectangle_int_t rect;
 
       gdk_window_move_resize (gtk_widget_get_window (widget),
 			      allocation->x + border_width,
@@ -869,6 +1035,48 @@ gtk_viewport_size_allocate (GtkWidget     *widget,
                               - gtk_adjustment_get_value (vadjustment),
                               child_allocation.width,
                               child_allocation.height);
+
+      surface_w = view_allocation.width;
+      if (child_allocation.width > view_allocation.width)
+	surface_w = MIN (surface_w + 64, child_allocation.width);
+
+      surface_h = view_allocation.height;
+      if (child_allocation.height > view_allocation.height)
+	surface_h = MIN (surface_h + 64, child_allocation.height);
+
+      if (priv->backing_surface != NULL &&
+	  (priv->backing_surface_w < view_allocation.width ||
+	   priv->backing_surface_w > surface_w + 32 ||
+	   priv->backing_surface_h < view_allocation.height ||
+	   priv->backing_surface_h > surface_h + 32))
+	{
+	  cairo_surface_destroy (priv->backing_surface);
+	  priv->backing_surface = NULL;
+	  if (priv->backing_surface_dirty)
+	    cairo_region_destroy (priv->backing_surface_dirty);
+	  priv->backing_surface_dirty = NULL;
+	}
+
+      if (priv->backing_surface == NULL &&
+	  (view_allocation.width < child_allocation.width ||
+	   view_allocation.height < child_allocation.height))
+	{
+	  priv->backing_surface_x = gtk_adjustment_get_value (hadjustment);
+	  priv->backing_surface_y = gtk_adjustment_get_value (vadjustment);
+	  priv->backing_surface_w = surface_w;
+	  priv->backing_surface_h = surface_h;
+	  priv->backing_surface_dirty = cairo_region_create ();
+	  priv->backing_surface =
+	    gdk_window_create_similar_surface (priv->bin_window,
+					       CAIRO_CONTENT_COLOR_ALPHA,
+					       surface_w, surface_h);
+	  rect.x = 0;
+	  rect.y = 0;
+	  rect.width = surface_w;
+	  rect.height = surface_h;
+	  cairo_region_union_rectangle (priv->backing_surface_dirty,
+					&rect);
+	}
     }
 
   child = gtk_bin_get_child (bin);

gtk/gtkwidget.c

@@ -854,9 +854,10 @@ static void gtk_widget_on_frame_clock_update (GdkFrameClock *frame_clock,
                                               GtkWidget     *widget);
 
 static gboolean event_window_is_still_viewable (GdkEvent *event);
+static void gtk_cairo_set_event_window (cairo_t        *cr,
+					GdkWindow *window);
 static void gtk_cairo_set_event (cairo_t        *cr,
 				 GdkEventExpose *event);
-static void gtk_widget_propagate_alpha (GtkWidget *widget);
 
 /* --- variables --- */
 static gpointer         gtk_widget_parent_class = NULL;
@@ -967,24 +968,9 @@ gtk_widget_draw_marshaller (GClosure     *closure,
                             gpointer      invocation_hint,
                             gpointer      marshal_data)
 {
-  GtkWidget *widget = g_value_get_object (&param_values[0]);
-  GdkEventExpose *tmp_event;
-  gboolean push_group;
   cairo_t *cr = g_value_get_boxed (&param_values[1]);
 
   cairo_save (cr);
-  tmp_event = _gtk_cairo_get_event (cr);
-
-  push_group =
-    widget->priv->opacity_group ||
-    (widget->priv->alpha != 255 &&
-     (!gtk_widget_get_has_window (widget) || tmp_event == NULL));
-
-  if (push_group)
-    {
-      cairo_push_group (cr);
-      gtk_cairo_set_event (cr, NULL);
-    }
 
   _gtk_marshal_BOOLEAN__BOXED (closure,
                                return_value,
@@ -994,14 +980,6 @@ gtk_widget_draw_marshaller (GClosure     *closure,
                                marshal_data);
 
 
-  if (push_group)
-    {
-      cairo_pop_group_to_source (cr);
-      cairo_set_operator (cr, CAIRO_OPERATOR_OVER);
-      cairo_paint_with_alpha (cr, widget->priv->alpha / 255.0);
-    }
-
-  gtk_cairo_set_event (cr, tmp_event);
   cairo_restore (cr);
 }
 
@@ -1014,9 +992,6 @@ gtk_widget_draw_marshallerv (GClosure     *closure,
 			     int           n_params,
 			     GType        *param_types)
 {
-  GtkWidget *widget = GTK_WIDGET (instance);
-  GdkEventExpose *tmp_event;
-  gboolean push_group;
   cairo_t *cr;
   va_list args_copy;
 
@@ -1024,18 +999,6 @@ gtk_widget_draw_marshallerv (GClosure     *closure,
   cr = va_arg (args_copy, gpointer);
 
   cairo_save (cr);
-  tmp_event = _gtk_cairo_get_event (cr);
-
-  push_group =
-    widget->priv->opacity_group ||
-    (widget->priv->alpha != 255 &&
-     (!gtk_widget_get_has_window (widget) || tmp_event == NULL));
-
-  if (push_group)
-    {
-      cairo_push_group (cr);
-      gtk_cairo_set_event (cr, NULL);
-    }
 
   _gtk_marshal_BOOLEAN__BOXEDv (closure,
 				return_value,
@@ -1046,14 +1009,6 @@ gtk_widget_draw_marshallerv (GClosure     *closure,
 				param_types);
 
 
-  if (push_group)
-    {
-      cairo_pop_group_to_source (cr);
-      cairo_set_operator (cr, CAIRO_OPERATOR_OVER);
-      cairo_paint_with_alpha (cr, widget->priv->alpha / 255.0);
-    }
-
-  gtk_cairo_set_event (cr, tmp_event);
   cairo_restore (cr);
 
   va_end (args_copy);
@@ -4203,8 +4158,6 @@ gtk_widget_unparent (GtkWidget *widget)
     g_object_notify_queue_clear (G_OBJECT (widget), nqueue);
   g_object_notify_queue_thaw (G_OBJECT (widget), nqueue);
 
-  gtk_widget_propagate_alpha (widget);
-
   gtk_widget_pop_verify_invariants (widget);
   g_object_unref (widget);
 }
@@ -6282,6 +6235,23 @@ gtk_widget_real_mnemonic_activate (GtkWidget *widget,
   return TRUE;
 }
 
+static const cairo_user_data_key_t event_window_key;
+
+GdkWindow *
+_gtk_cairo_get_event_window (cairo_t *cr)
+{
+  g_return_val_if_fail (cr != NULL, NULL);
+
+  return cairo_get_user_data (cr, &event_window_key);
+}
+
+static void
+gtk_cairo_set_event_window (cairo_t        *cr,
+			    GdkWindow *event_window)
+{
+  cairo_set_user_data (cr, &event_window_key, event_window, NULL);
+}
+
 static const cairo_user_data_key_t event_key;
 
 GdkEventExpose *
@@ -6294,7 +6264,7 @@ _gtk_cairo_get_event (cairo_t *cr)
 
 static void
 gtk_cairo_set_event (cairo_t        *cr,
-                     GdkEventExpose *event)
+		     GdkEventExpose *event)
 {
   cairo_set_user_data (cr, &event_key, event, NULL);
 }
@@ -6323,15 +6293,15 @@ gboolean
 gtk_cairo_should_draw_window (cairo_t *cr,
                               GdkWindow *window)
 {
-  GdkEventExpose *event;
+  GdkWindow *event_window;
 
   g_return_val_if_fail (cr != NULL, FALSE);
   g_return_val_if_fail (GDK_IS_WINDOW (window), FALSE);
 
-  event = _gtk_cairo_get_event (cr);
+  event_window = _gtk_cairo_get_event_window (cr);
 
-  return event == NULL ||
-         event->window == window;
+  return event_window == NULL ||
+    event_window == window;
 }
 
 static gboolean
@@ -6348,17 +6318,20 @@ gtk_widget_get_clip_draw (GtkWidget *widget)
   return TRUE;
 }
 
-/* code shared by gtk_container_propagate_draw() and
- * gtk_widget_draw()
- */
-void
+static void
 _gtk_widget_draw_internal (GtkWidget *widget,
                            cairo_t   *cr,
-                           gboolean   clip_to_size)
+                           gboolean   clip_to_size,
+			   GdkWindow *window)
 {
+  GdkWindow *tmp_event_window;
+
   if (!gtk_widget_is_drawable (widget))
     return;
 
+  tmp_event_window = _gtk_cairo_get_event_window (cr);
+  gtk_cairo_set_event_window (cr, window);
+
   clip_to_size &= gtk_widget_get_clip_draw (widget);
 
   if (clip_to_size)
@@ -6399,7 +6372,7 @@ _gtk_widget_draw_internal (GtkWidget *widget,
 #endif
 
       if (cairo_status (cr) &&
-          _gtk_cairo_get_event (cr))
+          _gtk_cairo_get_event_window (cr))
         {
           /* We check the event so we only warn about internal GTK calls.
            * Errors might come from PDF streams having write failures and
@@ -6411,6 +6384,77 @@ _gtk_widget_draw_internal (GtkWidget *widget,
                      cairo_status_to_string (cairo_status (cr)));
         }
     }
+
+  gtk_cairo_set_event_window (cr, tmp_event_window);
+}
+
+/* Emit draw() on the widget that owns window,
+   and on any child windows that also belong
+   to the widget. */
+static void
+_gtk_widget_draw_windows (GdkWindow *window,
+			  cairo_t *cr,
+			  int window_x,
+			  int window_y)
+{
+  cairo_pattern_t *pattern;
+  gboolean do_clip;
+  GtkWidget *widget = NULL;
+  GList *l;
+  int x, y;
+
+  if (!gdk_window_is_viewable (window))
+    return;
+
+  cairo_save (cr);
+  cairo_translate (cr, window_x, window_y);
+  cairo_rectangle (cr, 0, 0,
+		   gdk_window_get_width (window),
+		   gdk_window_get_height (window));
+  cairo_clip (cr);
+
+  if (gdk_cairo_get_clip_rectangle (cr, NULL))
+    {
+      cairo_save (cr);
+      pattern = gdk_window_get_background_pattern (window);
+      cairo_set_source (cr, pattern);
+      cairo_paint (cr);
+      cairo_restore (cr);
+
+      gdk_window_get_user_data (window, (gpointer *) &widget);
+      do_clip = _gtk_widget_get_translation_to_window (widget, window,
+						       &x, &y);
+      cairo_save (cr);
+      cairo_translate (cr, -x, -y);
+      _gtk_widget_draw_internal (widget, cr, do_clip, window);
+      cairo_restore (cr);
+
+      for (l = g_list_last (gdk_window_peek_children (window));
+	   l != NULL;
+	   l = l->prev)
+	{
+	  GdkWindow *child_window = l->data;
+	  gpointer child_data;
+	  GdkWindowType type;
+	  int wx, wy;
+
+	  type = gdk_window_get_window_type (child_window);
+	  if (!gdk_window_is_visible (child_window) ||
+	      gdk_window_is_input_only (child_window) ||
+	      type == GDK_WINDOW_OFFSCREEN ||
+	      type == GDK_WINDOW_FOREIGN)
+	    continue;
+
+	  gdk_window_get_user_data (child_window, &child_data);
+	  if (child_data == (gpointer)widget)
+	    {
+	      gdk_window_get_position (child_window, &wx, &wy);
+	      _gtk_widget_draw_windows (child_window, cr, wx,wy);
+	    }
+	}
+    }
+
+  cairo_restore (cr);
 }
 
 /**
@@ -6443,23 +6487,89 @@ void
 gtk_widget_draw (GtkWidget *widget,
                  cairo_t   *cr)
 {
-  GdkEventExpose *tmp_event;
+  GdkWindow *window, *child_window;
+  gpointer child_data;
+  GList *l;
+  int wx, wy;
+  gboolean push_group;
+  GdkWindowType type;
 
+  /* We get expose events only on native windows, so the draw
+   * implementation has to walk the entire widget hierarchy, except
+   * that it stops at native subwindows while we're in an expose
+   * event (_gtk_cairo_get_event () != NULL).
+   *
+   * However, we need to properly clip drawing into child windows
+   * to avoid drawing outside if widgets use e.g. cairo_paint(), so
+   * we traverse over GdkWindows as well as GtkWidgets.
+   *
+   * In order to be able to have opacity groups for entire widgets
+   * that consists of multiple windows we collect all the windows
+   * that belongs to a widget and draw them in one go. This means
+   * we may somewhat reorder GdkWindows when we paint them, but
+   * thats not generally a problem, as if you want a guaranteed
+   * order you generally use a windowed widget where you control
+   * the window hierarchy.
+   */
   g_return_if_fail (GTK_IS_WIDGET (widget));
   g_return_if_fail (!widget->priv->alloc_needed);
   g_return_if_fail (cr != NULL);
 
   cairo_save (cr);
-  /* We have to reset the event here so that draw functions can call
-   * gtk_widget_draw() on random other widgets and get the desired
-   * effect: Drawing all contents, not just the current window.
-   */
-  tmp_event = _gtk_cairo_get_event (cr);
-  gtk_cairo_set_event (cr, NULL);
 
-  _gtk_widget_draw_internal (widget, cr, TRUE);
+  push_group =
+    widget->priv->opacity_group ||
+    (widget->priv->alpha != 255 &&
+     !gtk_widget_is_toplevel (widget));
+
+  if (push_group)
+    cairo_push_group (cr);
+
+  window = gtk_widget_get_window (widget);
+  if (gtk_widget_get_has_window (widget))
+    {
+      /* The widget will be completely contained in its window, so just
+       * expose that (and any child window belonging to the widget) */
+      _gtk_widget_draw_windows (window, cr, 0, 0);
+    }
+  else
+    {
+      /* The widget draws in its parent window, so we send a draw() for
+       * that. */
+      _gtk_widget_draw_internal (widget, cr, TRUE, window);
+
+      /* But, it may also have child windows in the parent which we should
+       * draw (after having drawn on the parent) */
+      for (l = g_list_last (gdk_window_peek_children (window));
+	   l != NULL;
+	   l = l->prev)
+	{
+	  child_window = l->data;
+	  type = gdk_window_get_window_type (child_window);
+	  if (!gdk_window_is_visible (child_window) ||
+	      gdk_window_is_input_only (child_window) ||
+	      type == GDK_WINDOW_OFFSCREEN ||
+	      type == GDK_WINDOW_FOREIGN)
+	    continue;
+
+	  gdk_window_get_user_data (child_window, &child_data);
+	  if (child_data == (gpointer)widget)
+	    {
+	      gdk_window_get_position (child_window, &wx, &wy);
+	      _gtk_widget_draw_windows (child_window, cr,
+					wx - widget->priv->allocation.x,
+					wy - widget->priv->allocation.y);
+	    }
+	}
+    }
+
+  if (push_group)
+    {
+      cairo_pop_group_to_source (cr);
+      cairo_set_operator (cr, CAIRO_OPERATOR_OVER);
+      cairo_paint_with_alpha (cr, widget->priv->alpha / 255.0);
+    }
 
-  gtk_cairo_set_event (cr, tmp_event);
   cairo_restore (cr);
 }
 
@@ -6755,8 +6865,6 @@ gtk_widget_send_expose (GtkWidget *widget,
 {
   gboolean result = FALSE;
   cairo_t *cr;
-  int x, y;
-  gboolean do_clip;
 
   g_return_val_if_fail (GTK_IS_WIDGET (widget), TRUE);
   g_return_val_if_fail (gtk_widget_get_realized (widget), TRUE);
@@ -6764,21 +6872,18 @@ gtk_widget_send_expose (GtkWidget *widget,
   g_return_val_if_fail (event->type == GDK_EXPOSE, TRUE);
 
   cr = gdk_cairo_create (event->expose.window);
-  gtk_cairo_set_event (cr, &event->expose);
-
   gdk_cairo_region (cr, event->expose.region);
   cairo_clip (cr);
 
-  do_clip = _gtk_widget_get_translation_to_window (widget,
-						   event->expose.window,
-						   &x, &y);
-  cairo_translate (cr, -x, -y);
+  gtk_cairo_set_event (cr, &event->expose);
 
-  _gtk_widget_draw_internal (widget, cr, do_clip);
+  if (event->expose.window == widget->priv->window)
+    gtk_widget_draw (widget, cr);
+  else
+    _gtk_widget_draw_windows (event->expose.window, cr, 0, 0);
 
-  /* unset here, so if someone keeps a reference to cr we
-   * don't leak the window. */
   gtk_cairo_set_event (cr, NULL);
+
   cairo_destroy (cr);
 
   return result;
@@ -8460,6 +8565,9 @@ gtk_widget_get_app_paintable (GtkWidget *widget)
  * expose events, since even the clearing to the background color or
  * pixmap will not happen automatically (as it is done in
  * gdk_window_begin_paint_region()).
+ *
+ * Since 3.10 this function only works for widgets with native
+ * windows.
  **/
 void
 gtk_widget_set_double_buffered (GtkWidget *widget,
@@ -8718,8 +8826,6 @@ gtk_widget_set_parent (GtkWidget *widget,
       gtk_widget_queue_compute_expand (parent);
     }
 
-  gtk_widget_propagate_alpha (widget);
-
   gtk_widget_pop_verify_invariants (widget);
 }
 
@@ -14556,10 +14662,6 @@ gtk_widget_set_window (GtkWidget *widget,
     {
       priv->window = window;
 
-      if (gtk_widget_get_has_window (widget) && window != NULL && !gdk_window_has_native (window))
-	gdk_window_set_opacity (window,
-				priv->norender ? 0 : priv->alpha / 255.0);
-
       g_object_notify (G_OBJECT (widget), "window");
     }
 }
@@ -14698,86 +14800,8 @@ gtk_widget_set_support_multidevice (GtkWidget *widget,
  * in gtk_widget_set_opacity, secondly we can get it from the css opacity. These two
  * are multiplied together to form the total alpha. Secondly, the user can specify
  * an opacity group for a widget, which means we must essentially handle it as having alpha.
- *
- * We handle opacity in two ways. For a windowed widget, with opacity set but no opacity
- * group we directly set the opacity of widget->window. This will cause gdk to properly
- * redirect drawing inside the window to a buffer and do OVER paint_with_alpha.
- *
- * However, if the widget is not windowed, or the user specified an opacity group for the
- * widget we do the opacity handling in the ::draw marshaller for the widget. A naive
- * implementation of this would break for windowed widgets or descendant widgets with
- * windows, as these would not be handled by the ::draw signal. To handle this we set
- * all such gdkwindows as fully transparent and then override gtk_cairo_should_draw_window()
- * to make the draw signal propagate to *all* child widgets/windows.
- *
- * Note: We don't make all child windows fully transparent, we stop at the first one
- * in each branch when propagating down the hierarchy.
  */
 
-
-/* This is called when priv->alpha or priv->opacity_group group changes, and should
- * update priv->norender and GdkWindow opacity for this widget and any children that
- * needs changing. It is also called whenver the parent changes, the parents
- * norender_children state changes, or the has_window state of the widget changes.
- */
-static void
-gtk_widget_propagate_alpha (GtkWidget *widget)
-{
-  GtkWidgetPrivate *priv = widget->priv;
-  GtkWidget *parent;
-  gboolean norender, norender_children;
-  GList *l;
-
-  parent = priv->parent;
-
-  /* Norender affects only windowed widget and means don't render widget->window in the
-     normal fashion.
-     We only set this if the parent has norender_children, because:
-     a) For an opacity group (that does not have a norender_children parent) we still
-     need to render the window or we will never get an expose event.
-     b) For alpha we set the opacity of window->widget directly, so no other
-     work is needed.
-  */
-  norender = (parent != NULL && parent->priv->norender_children);
-
-  /* windows under this widget should not render if:
-     a) This widget has an opacity group
-     b) This widget has alpha and is no-windowed (otherwise we'd set alpha on widget->window)
-     c) This widget has norender but is no-windowed (a windowed widget would "swallow" the norender)
-  */
-  norender_children =
-    priv->opacity_group ||
-    (!gtk_widget_get_has_window (widget) &&
-     ( norender || priv->alpha != 255));
-
-  if (gtk_widget_get_has_window (widget))
-    {
-      if (priv->window != NULL &&
-	  (!gdk_window_has_native (priv->window) || gtk_widget_is_toplevel (widget)))
-	gdk_window_set_opacity (priv->window,
-				norender ? 0 : priv->alpha / 255.0);
-    }
-
-  for (l = priv->registered_windows; l != NULL; l = l->next)
-    {
-      GdkWindow *w = l->data;
-      if (w != priv->window && !gdk_window_has_native (w))
-	gdk_window_set_opacity (w, norender_children ? 0.0 : 1.0);
-    }
-
-  priv->norender = norender;
-  if (priv->norender_children != norender_children)
-    {
-      priv->norender_children = norender_children;
-
-      if (GTK_IS_CONTAINER (widget))
-	gtk_container_forall (GTK_CONTAINER (widget), (GtkCallback)gtk_widget_propagate_alpha, NULL);
-    }
-
-  if (gtk_widget_get_realized (widget))
-    gtk_widget_queue_draw (widget);
-}
-
 static void
 gtk_widget_update_alpha (GtkWidget *widget)
 {
@@ -14804,8 +14828,12 @@ gtk_widget_update_alpha (GtkWidget *widget)
 
   priv->alpha = alpha;
 
-  gtk_widget_propagate_alpha (widget);
+  if (gtk_widget_is_toplevel (widget))
+    gdk_window_set_opacity (priv->window,
+			    priv->alpha / 255.0);
 
+  if (gtk_widget_get_realized (widget))
+    gtk_widget_queue_draw (widget);
 }
 
 static void
@@ -14825,7 +14853,8 @@ gtk_widget_set_has_opacity_group  (GtkWidget *widget,
 
   priv->opacity_group = has_opacity_group;
 
-  gtk_widget_propagate_alpha (widget);
+  if (gtk_widget_get_realized (widget))
+    gtk_widget_queue_draw (widget);
 }
 
 /**

gtk/gtkwidgetprivate.h

@@ -89,11 +89,9 @@ const gchar*      _gtk_widget_get_accel_path               (GtkWidget *widget,
 
 AtkObject *       _gtk_widget_peek_accessible              (GtkWidget *widget);
 
+GdkWindow *       _gtk_cairo_get_event_window              (cairo_t *cr);
 GdkEventExpose *  _gtk_cairo_get_event                     (cairo_t *cr);
 
-void              _gtk_widget_draw_internal                (GtkWidget *widget,
-                                                            cairo_t   *cr,
-                                                            gboolean   clip_to_size);
 void              _gtk_widget_set_has_default              (GtkWidget *widget,
                                                             gboolean   has_default);
 void              _gtk_widget_set_has_grab                 (GtkWidget *widget,