compositor: get rid of initial black rectangle on xwayland clients

At the moment when a legacy X11 application client is first mapped it
gets briefly shown as a black rectangle before redrawing.

That behavior is because the initial Configure operation on the window
leads to the surface immediately getting full window damage posted by
Xwayland before the client has a chance to draw.

This commit changes mutter to send a sync request right away, when a
window first shows up, then waits until the reply from the application
before showing the window.

It leverages the same code paths already used to prevent flicker from
subsequent (non-initial) resizes on the window.

src/compositor/compositor.c

@@ -684,6 +684,9 @@ meta_compositor_sync_updates_frozen (MetaCompositor *compositor,
                                      MetaWindow     *window)
 {
   MetaWindowActor *window_actor = META_WINDOW_ACTOR (meta_window_get_compositor_private (window));
+  if (!window_actor)
+    return;
+
   meta_window_actor_sync_updates_frozen (window_actor);
 }
 

src/compositor/meta-surface-actor-wayland.c

@@ -99,6 +99,20 @@ meta_surface_actor_wayland_add_frame_callbacks (MetaSurfaceActorWayland *self,
   wl_list_insert_list (&priv->frame_callback_list, frame_callbacks);
 }
 
+static void
+meta_surface_actor_wayland_set_frozen (MetaSurfaceActor *actor,
+                                       gboolean          is_frozen)
+{
+  MetaSurfaceActorWayland *self = META_SURFACE_ACTOR_WAYLAND (actor);
+  MetaWaylandSurface *surface = meta_surface_actor_wayland_get_surface (self);
+
+  META_SURFACE_ACTOR_CLASS (meta_surface_actor_wayland_parent_class)->set_frozen (actor,
+                                                                                  is_frozen);
+
+  if (surface)
+    meta_wayland_surface_set_frozen (surface, is_frozen);
+}
+
 static MetaWindow *
 meta_surface_actor_wayland_get_window (MetaSurfaceActor *actor)
 {
@@ -111,6 +125,17 @@ meta_surface_actor_wayland_get_window (MetaSurfaceActor *actor)
   return surface->window;
 }
 
+static void
+meta_surface_actor_wayland_size_changed (MetaSurfaceActor *actor)
+{
+  MetaWindow *window;
+
+  window = meta_surface_actor_wayland_get_window (actor);
+
+  if (window)
+    meta_window_set_resize_pending (window, FALSE);
+}
+
 static void
 meta_surface_actor_wayland_get_preferred_width  (ClutterActor *actor,
                                                  gfloat        for_height,
@@ -220,8 +245,11 @@ meta_surface_actor_wayland_class_init (MetaSurfaceActorWaylandClass *klass)
   surface_actor_class->set_unredirected = meta_surface_actor_wayland_set_unredirected;
   surface_actor_class->is_unredirected = meta_surface_actor_wayland_is_unredirected;
 
+  surface_actor_class->set_frozen = meta_surface_actor_wayland_set_frozen;
   surface_actor_class->get_window = meta_surface_actor_wayland_get_window;
 
+  surface_actor_class->size_changed = meta_surface_actor_wayland_size_changed;
+
   object_class->dispose = meta_surface_actor_wayland_dispose;
 }
 

src/compositor/meta-surface-actor.c

@@ -31,6 +31,9 @@ struct _MetaSurfaceActorPrivate
 
 static void cullable_iface_init (MetaCullableInterface *iface);
 
+void meta_surface_actor_real_set_frozen (MetaSurfaceActor *self,
+                                         gboolean          frozen);
+
 G_DEFINE_ABSTRACT_TYPE_WITH_CODE (MetaSurfaceActor, meta_surface_actor, CLUTTER_TYPE_ACTOR,
                                   G_IMPLEMENT_INTERFACE (META_TYPE_CULLABLE, cullable_iface_init));
 
@@ -121,6 +124,8 @@ meta_surface_actor_class_init (MetaSurfaceActorClass *klass)
   object_class->dispose = meta_surface_actor_dispose;
   actor_class->pick = meta_surface_actor_pick;
 
+  klass->set_frozen = meta_surface_actor_real_set_frozen;
+
   signals[REPAINT_SCHEDULED] = g_signal_new ("repaint-scheduled",
                                              G_TYPE_FROM_CLASS (object_class),
                                              G_SIGNAL_RUN_LAST,
@@ -130,8 +135,8 @@ meta_surface_actor_class_init (MetaSurfaceActorClass *klass)
 
   signals[SIZE_CHANGED] = g_signal_new ("size-changed",
                                         G_TYPE_FROM_CLASS (object_class),
-                                        G_SIGNAL_RUN_LAST,
+                                        G_SIGNAL_RUN_FIRST,
-                                        0,
+                                        G_STRUCT_OFFSET (MetaSurfaceActorClass, size_changed),
                                         NULL, NULL, NULL,
                                         G_TYPE_NONE, 0);
 
@@ -331,6 +336,13 @@ meta_surface_actor_is_visible (MetaSurfaceActor *self)
 void
 meta_surface_actor_set_frozen (MetaSurfaceActor *self,
                                gboolean          frozen)
+{
+  return META_SURFACE_ACTOR_GET_CLASS (self)->set_frozen (self, frozen);
+}
+
+void
+meta_surface_actor_real_set_frozen (MetaSurfaceActor *self,
+                                    gboolean          frozen)
 {
   MetaSurfaceActorPrivate *priv = self->priv;
 

src/compositor/meta-surface-actor.h

@@ -36,7 +36,12 @@ struct _MetaSurfaceActorClass
                                   gboolean          unredirected);
   gboolean (* is_unredirected)   (MetaSurfaceActor *actor);
 
+  void     (* set_frozen)        (MetaSurfaceActor *actor,
+                                  gboolean          is_frozen);
+
   MetaWindow *(* get_window)      (MetaSurfaceActor *actor);
+
+  void     (* size_changed)      (MetaSurfaceActor *actor);
 };
 
 struct _MetaSurfaceActor

src/compositor/meta-window-actor.c

@@ -53,6 +53,8 @@ struct _MetaWindowActorPrivate
   MetaWindow *window;
   MetaCompositor *compositor;
 
+  MetaCompEffect  pending_effect;
+
   MetaSurfaceActor *surface;
 
   /* MetaShadowFactory only caches shadows that are actually in use;
@@ -117,6 +119,7 @@ struct _MetaWindowActorPrivate
 
   guint             updates_frozen         : 1;
   guint             first_frame_state      : 2; /* FirstFrameState */
+  guint             has_pending_effect     : 1;
 };
 
 typedef struct _FrameData FrameData;
@@ -296,6 +299,7 @@ surface_size_changed (MetaSurfaceActor *actor,
   MetaWindowActor *self = META_WINDOW_ACTOR (user_data);
 
   meta_window_actor_update_shape (self);
+  meta_window_actor_handle_updates (self);
 }
 
 static void
@@ -345,8 +349,11 @@ meta_window_actor_freeze (MetaWindowActor *self)
 {
   MetaWindowActorPrivate *priv = self->priv;
 
-  if (priv->freeze_count == 0 && priv->surface)
+  if (priv->freeze_count == 0)
-    meta_surface_actor_set_frozen (priv->surface, TRUE);
+    {
+      if (priv->surface)
+        meta_surface_actor_set_frozen (priv->surface, TRUE);
+    }
 
   priv->freeze_count ++;
 }
@@ -359,6 +366,12 @@ meta_window_actor_sync_thawed_state (MetaWindowActor *self)
   if (priv->first_frame_state == INITIALLY_FROZEN)
     priv->first_frame_state = DRAWING_FIRST_FRAME;
 
+  if (priv->has_pending_effect)
+    {
+      meta_window_actor_show (self, priv->pending_effect);
+      priv->has_pending_effect = FALSE;
+    }
+
   if (priv->surface)
     meta_surface_actor_set_frozen (priv->surface, FALSE);
 
@@ -1317,6 +1330,13 @@ meta_window_actor_show (MetaWindowActor   *self,
 
   g_return_if_fail (!priv->visible);
 
+  if (is_frozen (self))
+    {
+      priv->pending_effect = effect;
+      priv->has_pending_effect = TRUE;
+      return;
+    }
+
   self->priv->visible = TRUE;
 
   switch (effect)
@@ -1918,10 +1938,11 @@ meta_window_actor_handle_updates (MetaWindowActor *self)
 {
   MetaWindowActorPrivate *priv = self->priv;
 
-  if (is_frozen (self))
+  if (is_frozen (self) || meta_window_resize_is_pending (priv->window))
     {
-      /* The window is frozen due to a pending animation: we'll wait until
+      /* If the window is frozen due to a pending animation or a resize is
-       * the animation finishes to reshape and repair the window */
+       * pending then we'll wait until the animation or resize finishes to
+       * reshape and repair the window */
       return;
     }
 

src/core/window-private.h

@@ -407,6 +407,12 @@ struct _MetaWindow
   /* whether or not the window is from a program running on another machine */
   guint is_remote : 1;
 
+  /* if TRUE, the X server hasn't yet committed a new buffer following resize of the frame/client window */
+  guint resize_pending : 1;
+
+  /* if TRUE, the window frame has a redraw queued */
+  guint frame_redraw_pending : 1;
+
   /* if non-NULL, the bounds of the window frame */
   cairo_region_t *frame_bounds;
 
@@ -781,6 +787,12 @@ void meta_window_move_resize_internal (MetaWindow          *window,
                                        MetaMoveResizeFlags  flags,
                                        int                  gravity,
                                        MetaRectangle        frame_rect);
+void meta_window_set_resize_pending (MetaWindow *window,
+                                     gboolean    is_resize_pending);
+gboolean meta_window_resize_is_pending (MetaWindow  *window);
+
+void meta_window_set_frame_redraw_pending (MetaWindow *window,
+                                           gboolean    is_frame_redraw_pending);
 
 void meta_window_grab_op_began (MetaWindow *window, MetaGrabOp op);
 void meta_window_grab_op_ended (MetaWindow *window, MetaGrabOp op);

src/core/window.c

@@ -3730,6 +3730,9 @@ meta_window_updates_are_frozen (MetaWindow *window)
   if (window->sync_request_serial < window->sync_request_wait_serial)
     return TRUE;
 
+  if (window->frame_redraw_pending)
+    return TRUE;
+
   return FALSE;
 }
 
@@ -6311,6 +6314,28 @@ meta_window_update_resize (MetaWindow *window,
   update_resize (window, snap, x, y, force);
 }
 
+void
+meta_window_set_resize_pending (MetaWindow *window,
+                                gboolean    is_resize_pending)
+{
+  window->resize_pending = is_resize_pending;
+}
+
+gboolean
+meta_window_resize_is_pending (MetaWindow  *window)
+{
+  return window->resize_pending;
+}
+
+void
+meta_window_set_frame_redraw_pending (MetaWindow *window,
+                                      gboolean    is_frame_redraw_pending)
+{
+  window->frame_redraw_pending = is_frame_redraw_pending;
+
+  meta_compositor_sync_updates_frozen (window->display->compositor, window);
+}
+
 static void
 end_grab_op (MetaWindow *window,
              const ClutterEvent *event)

src/ui/frames.c

@@ -149,6 +149,7 @@ static void
 invalidate_whole_window (MetaUIFrame *frame)
 {
   gdk_window_invalidate_rect (frame->window, NULL, FALSE);
+  meta_window_set_frame_redraw_pending (frame->meta_window, TRUE);
 }
 
 static MetaStyleInfo *
@@ -484,6 +485,27 @@ meta_ui_frame_attach_style (MetaUIFrame *frame)
                                                                             variant));
 }
 
+static void
+after_paint (GdkFrameClock *frame_clock,
+             MetaUIFrame   *frame)
+{
+  MetaFrames *frames = frame->frames;
+  MetaWindow *window = frame->meta_window;
+
+  /* Make sure the damage is posted to the X server before
+   * we mark the frame redraw finished and unfreeze, so there's
+   * a wayland surface commit waiting for us at unfreeze time
+   */
+  if (meta_is_wayland_compositor ())
+    gdk_display_sync (gtk_widget_get_display (GTK_WIDGET (frames)));
+
+  meta_window_set_frame_redraw_pending (window, FALSE);
+
+  g_signal_handlers_disconnect_by_func (G_OBJECT (gdk_window_get_frame_clock (frame->window)),
+                                        G_CALLBACK (after_paint),
+                                        frame);
+}
+
 MetaUIFrame *
 meta_frames_manage_window (MetaFrames *frames,
                            MetaWindow *meta_window,
@@ -531,6 +553,10 @@ meta_ui_frame_unmanage (MetaUIFrame *frame)
                                frame->xwindow,
                                META_CURSOR_DEFAULT);
 
+  g_signal_handlers_disconnect_by_func (G_OBJECT (gdk_window_get_frame_clock (frame->window)),
+                                        G_CALLBACK (after_paint),
+                                        frame);
+
   gdk_window_set_user_data (frame->window, NULL);
 
   g_hash_table_remove (frames->frames, &frame->xwindow);
@@ -1396,6 +1422,11 @@ meta_frames_draw (GtkWidget *widget,
   meta_ui_frame_paint (frame, cr);
   cairo_region_destroy (region);
 
+  g_signal_connect (G_OBJECT (gdk_window_get_frame_clock (frame->window)),
+                    "after-paint",
+                    G_CALLBACK (after_paint),
+                    frame);
+
   return TRUE;
 }
 

src/wayland/meta-wayland-surface.c

@@ -703,6 +703,9 @@ cleanup:
 static void
 meta_wayland_surface_commit (MetaWaylandSurface *surface)
 {
+  if (surface->is_frozen)
+    return;
+
   /*
    * If this is a sub-surface and it is in effective synchronous mode, only
    * cache the pending surface state until either one of the following two
@@ -1099,6 +1102,7 @@ meta_wayland_surface_set_window (MetaWaylandSurface *surface,
                                "position-changed",
                                G_CALLBACK (window_position_changed),
                                surface, 0);
+      meta_window_set_resize_pending (window, FALSE);
     }
 }
 
@@ -1719,3 +1723,16 @@ meta_wayland_surface_is_shortcuts_inhibited (MetaWaylandSurface *surface,
 
   return g_hash_table_contains (surface->shortcut_inhibited_seats, seat);
 }
+
+void
+meta_wayland_surface_set_frozen (MetaWaylandSurface *surface,
+                                 gboolean            is_frozen)
+{
+  if (surface->is_frozen == is_frozen)
+    return;
+
+  surface->is_frozen = is_frozen;
+
+  if (!surface->is_frozen && surface->pending)
+    meta_wayland_surface_commit (surface);
+}

src/wayland/meta-wayland-surface.h

@@ -203,6 +203,8 @@ struct _MetaWaylandSurface
 
   /* table of seats for which shortcuts are inhibited */
   GHashTable *shortcut_inhibited_seats;
+
+  guint32 is_frozen : 1;
 };
 
 void                meta_wayland_shell_init     (MetaWaylandCompositor *compositor);
@@ -302,5 +304,7 @@ void                meta_wayland_surface_restore_shortcuts (MetaWaylandSurface *
 
 gboolean            meta_wayland_surface_is_shortcuts_inhibited (MetaWaylandSurface *surface,
                                                                  MetaWaylandSeat    *seat);
+void                meta_wayland_surface_set_frozen (MetaWaylandSurface *surface,
+                                                     gboolean            is_frozen);
 
 #endif

src/wayland/meta-window-xwayland.c

@@ -71,6 +71,20 @@ meta_window_xwayland_shortcuts_inhibited (MetaWindow         *window,
   return meta_wayland_compositor_is_shortcuts_inhibited (compositor, source);
 }
 
+static void
+meta_window_xwayland_move_resize_internal (MetaWindow                *window,
+                                           int                        gravity,
+                                           MetaRectangle              unconstrained_rect,
+                                           MetaRectangle              constrained_rect,
+                                           MetaMoveResizeFlags        flags,
+                                           MetaMoveResizeResultFlags *result)
+{
+  META_WINDOW_CLASS (meta_window_xwayland_parent_class)->move_resize_internal (window, gravity, unconstrained_rect, constrained_rect, flags, result);
+
+  if (*result & META_MOVE_RESIZE_RESULT_RESIZED)
+    meta_window_set_resize_pending (window, TRUE);
+}
+
 static void
 meta_window_xwayland_get_property (GObject    *object,
                                    guint       prop_id,
@@ -117,6 +131,7 @@ meta_window_xwayland_class_init (MetaWindowXwaylandClass *klass)
 
   window_class->force_restore_shortcuts = meta_window_xwayland_force_restore_shortcuts;
   window_class->shortcuts_inhibited = meta_window_xwayland_shortcuts_inhibited;
+  window_class->move_resize_internal = meta_window_xwayland_move_resize_internal;
 
   gobject_class->get_property = meta_window_xwayland_get_property;
   gobject_class->set_property = meta_window_xwayland_set_property;

src/x11/window-x11.c

@@ -1244,8 +1244,9 @@ meta_window_x11_move_resize_internal (MetaWindow                *window,
     {
       meta_error_trap_push (window->display);
 
-      if (window == window->display->grab_window &&
+      if ((window->constructing ||
-          meta_grab_op_is_resizing (window->display->grab_op) &&
+          (window == window->display->grab_window &&
+           meta_grab_op_is_resizing (window->display->grab_op))) &&
           !window->disable_sync &&
           window->sync_request_counter != None &&
           window->sync_request_alarm != None &&
@@ -3496,27 +3497,32 @@ meta_window_x11_update_sync_request_counter (MetaWindow *window,
   window->sync_request_serial = new_counter_value;
   meta_compositor_sync_updates_frozen (window->display->compositor, window);
 
-  if (window == window->display->grab_window &&
+  if (new_counter_value >= window->sync_request_wait_serial && window->sync_request_timeout_id)
-      meta_grab_op_is_resizing (window->display->grab_op) &&
-      new_counter_value >= window->sync_request_wait_serial &&
-      (!window->extended_sync_request_counter || new_counter_value % 2 == 0) &&
-      window->sync_request_timeout_id)
     {
-      meta_topic (META_DEBUG_RESIZING,
+	if (!window->extended_sync_request_counter || new_counter_value % 2 == 0)
-                  "Alarm event received last motion x = %d y = %d\n",
+         {
-                  window->display->grab_latest_motion_x,
+	   g_source_remove (window->sync_request_timeout_id);
-                  window->display->grab_latest_motion_y);
+	   window->sync_request_timeout_id = 0;
+	 }
 
-      g_source_remove (window->sync_request_timeout_id);
+	if (window == window->display->grab_window &&
-      window->sync_request_timeout_id = 0;
+	    meta_grab_op_is_resizing (window->display->grab_op) &&
+            !meta_window_resize_is_pending (window) &&
+	    (!window->extended_sync_request_counter || new_counter_value % 2 == 0))
+	  {
+	    meta_topic (META_DEBUG_RESIZING,
+			"Alarm event received last motion x = %d y = %d\n",
+			 window->display->grab_latest_motion_x,
+			 window->display->grab_latest_motion_y);
 
-      /* This means we are ready for another configure;
+	    /* This means we are ready for another configure;
-       * no pointer round trip here, to keep in sync */
+	     * no pointer round trip here, to keep in sync */
-      meta_window_update_resize (window,
+	    meta_window_update_resize (window,
-                                 window->display->grab_last_user_action_was_snap,
+                                       window->display->grab_last_user_action_was_snap,
-                                 window->display->grab_latest_motion_x,
+                                       window->display->grab_latest_motion_x,
-                                 window->display->grab_latest_motion_y,
+                                       window->display->grab_latest_motion_y,
-                                 TRUE);
+                                       TRUE);
+	  }
     }
 
   /* If sync was previously disabled, turn it back on and hope