Move _NET_WM_WINDOW_OPACITY handling to the standard window-props interface

This removes one X11 dependency that the MetaWindowActor interface has,
making it easier for us to use Wayland on this one...

https://bugzilla.gnome.org/show_bug.cgi?id=720106

src/compositor/compositor-private.h

@@ -17,7 +17,6 @@ struct _MetaCompositor
 {
   MetaDisplay    *display;
 
-  Atom            atom_net_wm_window_opacity;
   guint           repaint_func_id;
 
   ClutterActor   *shadow_src;

src/compositor/compositor.c

@@ -175,31 +175,6 @@ process_damage (MetaCompositor     *compositor,
   meta_window_actor_process_damage (window_actor, event);
 }
 
-static void
-process_property_notify (MetaCompositor	*compositor,
-                         XPropertyEvent *event,
-                         MetaWindow     *window)
-{
-  MetaWindowActor *window_actor;
-
-  if (window == NULL)
-    return;
-
-  window_actor = META_WINDOW_ACTOR (meta_window_get_compositor_private (window));
-  if (window_actor == NULL)
-    return;
-
-  /* Check for the opacity changing */
-  if (event->atom == compositor->atom_net_wm_window_opacity)
-    {
-      meta_window_actor_update_opacity (window_actor);
-      DEBUG_TRACE ("process_property_notify: net_wm_window_opacity\n");
-      return;
-    }
-
-  DEBUG_TRACE ("process_property_notify: unknown\n");
-}
-
 static Window
 get_output_window (MetaScreen *screen)
 {
@@ -877,6 +852,18 @@ meta_compositor_window_shape_changed (MetaCompositor *compositor,
   meta_window_actor_update_shape (window_actor);
 }
 
+void
+meta_compositor_window_opacity_changed (MetaCompositor *compositor,
+                                        MetaWindow     *window)
+{
+  MetaWindowActor *window_actor;
+  window_actor = META_WINDOW_ACTOR (meta_window_get_compositor_private (window));
+  if (!window_actor)
+    return;
+
+  meta_window_actor_update_opacity (window_actor);
+}
+
 /* Clutter makes the assumption that there is only one X window
  * per stage, which is a valid assumption to make for a generic
  * application toolkit. As such, it will ignore any events sent
@@ -983,13 +970,6 @@ meta_compositor_process_event (MetaCompositor *compositor,
 	}
     }
 
-  switch (event->type)
-    {
-    case PropertyNotify:
-      process_property_notify (compositor, (XPropertyEvent *) event, window);
-      break;
-
-    default:
   if (event->type == meta_display_get_damage_event_base (compositor->display) + XDamageNotify)
     {
       /* Core code doesn't handle damage events, so we need to extract the MetaWindow
@@ -1004,8 +984,6 @@ meta_compositor_process_event (MetaCompositor *compositor,
       DEBUG_TRACE ("meta_compositor_process_event (process_damage)\n");
       process_damage (compositor, (XDamageNotifyEvent *) event, window);
     }
-      break;
-    }
 
   /* Clutter needs to know about MapNotify events otherwise it will
      think the stage is invisible */
@@ -1508,12 +1486,7 @@ on_shadow_factory_changed (MetaShadowFactory *factory,
 MetaCompositor *
 meta_compositor_new (MetaDisplay *display)
 {
-  char *atom_names[] = {
-    "_NET_WM_WINDOW_OPACITY",
-  };
-  Atom                   atoms[G_N_ELEMENTS(atom_names)];
   MetaCompositor        *compositor;
-  Display               *xdisplay = meta_display_get_xdisplay (display);
 
   if (!composite_at_least_version (display, 0, 3))
     return NULL;
@@ -1525,17 +1498,11 @@ meta_compositor_new (MetaDisplay *display)
   if (g_getenv("META_DISABLE_MIPMAPS"))
     compositor->no_mipmaps = TRUE;
 
-  meta_verbose ("Creating %d atoms\n", (int) G_N_ELEMENTS (atom_names));
-  XInternAtoms (xdisplay, atom_names, G_N_ELEMENTS (atom_names),
-                False, atoms);
-
   g_signal_connect (meta_shadow_factory_get_default (),
                     "changed",
                     G_CALLBACK (on_shadow_factory_changed),
                     compositor);
 
-  compositor->atom_net_wm_window_opacity = atoms[0];
-
   compositor->repaint_func_id = clutter_threads_add_repaint_func (meta_repaint_func,
                                                                   compositor,
                                                                   NULL);

src/compositor/meta-window-actor.c

@@ -68,8 +68,6 @@ struct _MetaWindowActorPrivate
 
   Damage            damage;
 
-  guint8            opacity;
-
   /* A region that matches the shape of the window, including frame bounds */
   cairo_region_t   *shape_region;
   /* If the window has an input shape, a region that matches the shape */
@@ -270,7 +268,6 @@ meta_window_actor_init (MetaWindowActor *self)
   priv = self->priv = G_TYPE_INSTANCE_GET_PRIVATE (self,
 						   META_TYPE_WINDOW_ACTOR,
 						   MetaWindowActorPrivate);
-  priv->opacity = 0xff;
   priv->shadow_class = NULL;
 }
 
@@ -319,6 +316,15 @@ window_appears_focused_notify (MetaWindow *mw,
   clutter_actor_queue_redraw (CLUTTER_ACTOR (data));
 }
 
+static gboolean
+is_non_opaque (MetaWindowActor *self)
+{
+  MetaWindowActorPrivate *priv = self->priv;
+  MetaWindow *window = priv->window;
+
+  return priv->argb32 || (window->opacity != 0xFF);
+}
+
 static void
 meta_window_actor_constructed (GObject *object)
 {
@@ -596,7 +602,7 @@ clip_shadow_under_window (MetaWindowActor *self)
 {
   MetaWindowActorPrivate *priv = self->priv;
 
-  return (priv->argb32 || priv->opacity != 0xff) && priv->window->frame;
+  return is_non_opaque (self) && priv->window->frame;
 }
 
 static void
@@ -622,6 +628,7 @@ meta_window_actor_paint (ClutterActor *actor)
       MetaShadowParams params;
       cairo_rectangle_int_t shape_bounds;
       cairo_region_t *clip = priv->shadow_clip;
+      MetaWindow *window = priv->window;
 
       meta_window_actor_get_shape_bounds (self, &shape_bounds);
       meta_window_actor_get_shadow_params (self, appears_focused, &params);
@@ -645,7 +652,7 @@ meta_window_actor_paint (ClutterActor *actor)
                          params.y_offset + shape_bounds.y,
                          shape_bounds.width,
                          shape_bounds.height,
-                         (clutter_actor_get_paint_opacity (actor) * params.opacity * priv->opacity) / (255 * 255),
+                         (clutter_actor_get_paint_opacity (actor) * params.opacity * window->opacity) / (255 * 255),
                          clip,
                          clip_shadow_under_window (self)); /* clip_strictly - not just as an optimization */
 
@@ -732,10 +739,10 @@ meta_window_actor_has_shadow (MetaWindowActor *self)
     return TRUE;
 
   /*
-   * Do not add shadows to ARGB windows; eventually we should generate a
-   * shadow from the input shape for such windows.
+   * Do not add shadows to non-opaque windows; eventually we should generate
+   * a shadow from the input shape for such windows.
    */
-  if (priv->argb32 || priv->opacity != 0xff)
+  if (is_non_opaque (self))
     return FALSE;
 
   /*
@@ -1270,7 +1277,7 @@ meta_window_actor_should_unredirect (MetaWindowActor *self)
   if (meta_window_requested_dont_bypass_compositor (metaWindow))
     return FALSE;
 
-  if (priv->opacity != 0xff)
+  if (metaWindow->opacity != 0xFF)
     return FALSE;
 
   if (metaWindow->shape_region != NULL)
@@ -1645,8 +1652,9 @@ static cairo_region_t *
 meta_window_actor_get_obscured_region (MetaWindowActor *self)
 {
   MetaWindowActorPrivate *priv = self->priv;
+  MetaWindow *window = priv->window;
 
-  if (priv->back_pixmap && priv->opacity == 0xff && !priv->window->shaded)
+  if (priv->back_pixmap && window->opacity != 0xFF && !priv->window->shaded)
     return priv->opaque_region;
   else
     return NULL;
@@ -2560,23 +2568,9 @@ void
 meta_window_actor_update_opacity (MetaWindowActor *self)
 {
   MetaWindowActorPrivate *priv = self->priv;
-  MetaDisplay *display = meta_screen_get_display (priv->screen);
-  MetaCompositor *compositor = meta_display_get_compositor (display);
-  Window xwin = meta_window_get_xwindow (priv->window);
-  gulong value;
-  guint8 opacity;
+  MetaWindow *window = priv->window;
 
-  if (meta_prop_get_cardinal (display, xwin,
-                              compositor->atom_net_wm_window_opacity,
-                              &value))
-    {
-      opacity = (guint8)((gfloat)value * 255.0 / ((gfloat)0xffffffff));
-    }
-  else
-    opacity = 255;
-
-  self->priv->opacity = opacity;
-  clutter_actor_set_opacity (self->priv->actor, opacity);
+  clutter_actor_set_opacity (self->priv->actor, window->opacity);
 }
 
 void

src/core/window-private.h

@@ -355,6 +355,9 @@ struct _MetaWindow
   /* the input shape region for picking */
   cairo_region_t *input_region;
 
+  /* _NET_WM_WINDOW_OPACITY */
+  guint opacity;
+
   /* if TRUE, the we have the new form of sync request counter which
    * also handles application frames */
   guint extended_sync_request_counter : 1;
@@ -695,6 +698,8 @@ void meta_window_update_input_region_x11  (MetaWindow *window);
 void meta_window_set_shape_region         (MetaWindow     *window,
                                            cairo_region_t *region);
 void meta_window_update_shape_region_x11  (MetaWindow *window);
+void meta_window_set_opacity              (MetaWindow *window,
+                                           guint       opacity);
 
 Window meta_window_get_toplevel_xwindow (MetaWindow *window);
 

src/core/window-props.c

@@ -1709,6 +1709,20 @@ reload_bypass_compositor (MetaWindow    *window,
   window->bypass_compositor = requested_value;
 }
 
+static void
+reload_window_opacity (MetaWindow    *window,
+                       MetaPropValue *value,
+                       gboolean       initial)
+
+{
+  int requested_value = 0xFF;
+
+  if (value->type != META_PROP_VALUE_INVALID)
+    requested_value = (int) value->v.cardinal;
+
+  meta_window_set_opacity (window, requested_value);
+}
+
 #define RELOAD_STRING(var_name, propname) \
   static void                                       \
   reload_ ## var_name (MetaWindow    *window,       \
@@ -1811,6 +1825,7 @@ meta_display_init_window_prop_hooks (MetaDisplay *display)
     { display->atom__NET_WM_STRUT,         META_PROP_VALUE_INVALID, reload_struts,            FALSE, FALSE },
     { display->atom__NET_WM_STRUT_PARTIAL, META_PROP_VALUE_INVALID, reload_struts,            FALSE, FALSE },
     { display->atom__NET_WM_BYPASS_COMPOSITOR, META_PROP_VALUE_CARDINAL,  reload_bypass_compositor, FALSE, FALSE },
+    { display->atom__NET_WM_WINDOW_OPACITY, META_PROP_VALUE_CARDINAL, reload_window_opacity,  TRUE, TRUE },
     { 0 },
   };
 

src/core/window.c

@@ -1201,6 +1201,8 @@ meta_window_new_with_attrs (MetaDisplay       *display,
    */
   window->stable_sequence = ++display->window_sequence_counter;
 
+  window->opacity = 0xFF;
+
   /* assign the window to its group, or create a new group if needed
    */
   window->group = NULL;
@@ -11444,3 +11446,13 @@ meta_window_get_toplevel_xwindow (MetaWindow *window)
 {
   return window->frame ? window->frame->xwindow : window->xwindow;
 }
+
+void
+meta_window_set_opacity (MetaWindow *window,
+                         guint       opacity)
+{
+  window->opacity = opacity;
+
+  if (window->display->compositor)
+    meta_compositor_window_opacity_changed (window->display->compositor, window);
+}

src/meta/atomnames.h

@@ -179,6 +179,7 @@ item(_NET_WM_BYPASS_COMPOSITOR)
 item(_NET_WM_OPAQUE_REGION)
 item(_NET_WM_FRAME_DRAWN)
 item(_NET_WM_FRAME_TIMINGS)
+item(_NET_WM_WINDOW_OPACITY)
 
 #if 0
 /* We apparently never use: */

src/meta/compositor.h

@@ -66,6 +66,8 @@ void meta_compositor_unmanage_screen (MetaCompositor *compositor,
 
 void meta_compositor_window_shape_changed (MetaCompositor *compositor,
                                            MetaWindow     *window);
+void meta_compositor_window_opacity_changed (MetaCompositor *compositor,
+                                             MetaWindow     *window);
 
 gboolean meta_compositor_process_event (MetaCompositor *compositor,
                                         XEvent         *event,