ClutterActor now has all the API and capabilities for being a concrete
class:
- layout management, through delegation
- container implementation and API
- background color
This means that a simple scene can be built straight out of actors
without using subclasses except for the Stage.
This is the first step towards the deprecation of most of the Actor
subclasses provided by Clutter.
And make sure that overriding Container and calling
clutter_actor_add_child() will result in the same sequence of operations
as the current set_parent()+queue_relayout()+signal_emit pattern.
Existing containers can continue using:
clutter_actor_set_parent (child, CLUTTER_ACTOR (container));
clutter_actor_queue_relayout (CLUTTER_ACTOR (container));
g_signal_emit_by_name (container, "actor-added", child);
and newly written containers overriding Container.add() can simply call:
clutter_actor_add_child (CLUTTER_ACTOR (container), child);
instead.