diff --git a/clutter/clutter-actor.c b/clutter/clutter-actor.c index 87aba079a..ce699b50f 100644 --- a/clutter/clutter-actor.c +++ b/clutter/clutter-actor.c @@ -222,13 +222,22 @@ * * Evaluates to %TRUE if the %CLUTTER_ACTOR_MAPPED flag is set. * - * Means "the actor will be painted if the stage is mapped." + * The mapped state is set when the actor is visible and all its parents up + * to a top-level (e.g. a #ClutterStage) are visible, realized, and mapped. * - * %TRUE if the actor is visible; and all parents with possible exception - * of the stage are visible; and an ancestor of the actor is a toplevel. + * This check can be used to see if an actor is going to be painted, as only + * actors with the %CLUTTER_ACTOR_MAPPED flag set are going to be painted. * - * Clutter auto-maintains the mapped flag whenever actors are - * reparented or shown/hidden. + * The %CLUTTER_ACTOR_MAPPED flag is managed by Clutter itself, and it should + * not be checked directly; instead, the recommended usage is to connect a + * handler on the #GObject::notify signal for the #ClutterActor:mapped + * property of #ClutterActor, and check the presence of + * the %CLUTTER_ACTOR_MAPPED flag on state changes. + * + * It is also important to note that Clutter may delay the changes of + * the %CLUTTER_ACTOR_MAPPED flag on top-levels due to backend-specific + * limitations, or during the reparenting of an actor, to optimize + * unnecessary (and potentially expensive) state changes. * * Since: 0.2 */ @@ -243,7 +252,7 @@ * actor wants to delay allocating resources until it is attached to a * stage, it may use the realize state to do so. However it is * perfectly acceptable for an actor to allocate Cogl resources before - * being realized because there is only one GL context used by Clutter + * being realized because there is only one drawing context used by Clutter * so any resources will work on any stage. If an actor is mapped it * must also be realized, but an actor can be realized and unmapped * (this is so hiding an actor temporarily doesn't do an expensive @@ -264,7 +273,7 @@ * * Note that an actor is only painted onscreen if it's mapped, which * means it's visible, and all its parents are visible, and one of the - * parents is a toplevel stage. + * parents is a toplevel stage; see also %CLUTTER_ACTOR_IS_MAPPED. * * Since: 0.2 */