clutter/actor: Emit a signal when the stage-views an actor is on change

Add a new signal that's emitted when the stage views an actor being
painted on have changed, "stage-views-changed". For example this signal
can be helpful when tracking whether an actor is painted on multiple
stage views or only one.

Since we must clear the stage-views list when an actor leaves the stage
(actors that aren't attached to a stage don't get notified about the
stage views being changed/replaced), we also emit the new signal when an
actor gets detached from the stage (otherwise there would be an edge
case where no signal is emitted but it really should: An actor is
visible on a stage view, then detached from the stage, and then attached
again and immeditely moved outside the view).

Also skip the comparison of the old stage-views list and the new one if
nobody is listening to the signal to save some resources.

https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1196
This commit is contained in:
Jonas Dreßler 2020-04-10 00:59:05 +02:00 committed by Carlos Garnacho
parent 675a97d58e
commit 18c792d6f8

View File

@ -1020,6 +1020,7 @@ enum
TRANSITIONS_COMPLETED,
TOUCH_EVENT,
TRANSITION_STOPPED,
STAGE_VIEWS_CHANGED,
LAST_SIGNAL
};
@ -4421,7 +4422,7 @@ clutter_actor_remove_child_internal (ClutterActor *self,
* to the stage views, so make sure all the stage-views lists are
* cleared as the child and its children leave the actor tree.
*/
if (clear_stage_views)
if (clear_stage_views && !CLUTTER_ACTOR_IN_DESTRUCTION (child))
clutter_actor_clear_stage_views_recursive (child);
if (emit_parent_set && !CLUTTER_ACTOR_IN_DESTRUCTION (child))
@ -8634,6 +8635,27 @@ clutter_actor_class_init (ClutterActorClass *klass)
g_signal_set_va_marshaller (actor_signals[TOUCH_EVENT],
G_TYPE_FROM_CLASS (object_class),
_clutter_marshal_BOOLEAN__BOXEDv);
/**
* ClutterActor::stage-views-changed:
* @actor: a #ClutterActor
*
* The ::stage-views-changed signal is emitted when the position or
* size an actor is being painted at have changed so that it's visible
* on different stage views.
*
* This signal is also emitted when the actor gets detached from the stage
* or when the views of the stage have been invalidated and will be
* replaced; it's not emitted when the actor gets hidden.
*/
actor_signals[STAGE_VIEWS_CHANGED] =
g_signal_new (I_("stage-views-changed"),
G_TYPE_FROM_CLASS (object_class),
G_SIGNAL_RUN_LAST,
0,
NULL, NULL, NULL,
G_TYPE_NONE, 0);
}
static void
@ -17540,10 +17562,15 @@ clear_stage_views_cb (ClutterActor *actor,
int depth,
gpointer user_data)
{
g_autoptr (GList) old_stage_views = NULL;
actor->priv->needs_update_stage_views = TRUE;
actor->priv->needs_compute_resource_scale = TRUE;
g_clear_pointer (&actor->priv->stage_views, g_list_free);
old_stage_views = g_steal_pointer (&actor->priv->stage_views);
if (old_stage_views)
g_signal_emit (actor, actor_signals[STAGE_VIEWS_CHANGED], 0);
return CLUTTER_ACTOR_TRAVERSE_VISIT_CONTINUE;
}
@ -17645,20 +17672,44 @@ clutter_actor_get_resource_scale (ClutterActor *self,
return FALSE;
}
static gboolean
sorted_lists_equal (GList *list_a,
GList *list_b)
{
GList *a, *b;
if (!list_a && !list_b)
return TRUE;
for (a = list_a, b = list_b;
a && b;
a = a->next, b = b->next)
{
if (a->data != b->data)
break;
if (!a->next && !b->next)
return TRUE;
}
return FALSE;
}
static void
update_stage_views (ClutterActor *self)
{
ClutterActorPrivate *priv = self->priv;
g_autoptr (GList) old_stage_views = NULL;
ClutterStage *stage;
graphene_rect_t bounding_rect;
g_clear_pointer (&priv->stage_views, g_list_free);
old_stage_views = g_steal_pointer (&priv->stage_views);
if (priv->needs_allocation)
{
g_warning ("Can't update stage views actor %s is on because it needs an "
"allocation.", _clutter_actor_get_debug_name (self));
return;
goto out;
}
stage = CLUTTER_STAGE (_clutter_actor_get_stage_internal (self));
@ -17673,10 +17724,18 @@ update_stage_views (ClutterActor *self)
if (bounding_rect.size.width == 0.0 ||
bounding_rect.size.height == 0.0)
return;
goto out;
priv->stage_views = clutter_stage_get_views_for_rect (stage,
&bounding_rect);
out:
if (g_signal_has_handler_pending (self, actor_signals[STAGE_VIEWS_CHANGED],
0, TRUE))
{
if (!sorted_lists_equal (old_stage_views, priv->stage_views))
g_signal_emit (self, actor_signals[STAGE_VIEWS_CHANGED], 0);
}
}
void