mirror of
https://github.com/brl/mutter.git
synced 2024-11-13 01:36:10 -05:00
89 lines
3.4 KiB
C
89 lines
3.4 KiB
C
/**
|
|
* SECTION:clutter-constraint
|
|
* @Title: ClutterConstraint
|
|
* @Short_Description: Abstract class for constraints on position or size
|
|
* @See_Also: #ClutterAction
|
|
*
|
|
* #ClutterConstraint is a base abstract class for modifiers of a #ClutterActor
|
|
* position or size.
|
|
*
|
|
* A #ClutterConstraint sub-class should contain the logic for modifying
|
|
* the position or size of the #ClutterActor to which it is applied, by
|
|
* updating the actor's allocation. Each #ClutterConstraint can change the
|
|
* allocation of the actor to which they are applied by overriding the
|
|
* <function>update_allocation()</function> virtual function.
|
|
*
|
|
* <refsect2 id="ClutterConstraint-implementation">
|
|
* <title>Implemting a ClutterConstraint</title>
|
|
* <para>Creating a sub-class of #ClutterConstraint requires the
|
|
* implementation of the <function>update_allocation()</function>
|
|
* virtual function.</para>
|
|
* <para>The <function>update_allocation()</function> virtual function
|
|
* is called during the allocation sequence of a #ClutterActor, and
|
|
* allows any #ClutterConstraint attached to that actor to modify the
|
|
* allocation before it is passed to the <function>allocate()</function>
|
|
* implementation.</para>
|
|
* <para>The #ClutterActorBox passed to the
|
|
* <function>update_allocation()</function> implementation contains the
|
|
* original allocation of the #ClutterActor, plus the eventual modifications
|
|
* applied by the other #ClutterConstraint<!-- -->s.</para>
|
|
* <note><para>Constraints are queried in the same order as they were
|
|
* applied using clutter_actor_add_constraint() or
|
|
* clutter_actor_add_constraint_with_name().</para></note>
|
|
* <para>It is not necessary for a #ClutterConstraint sub-class to chain
|
|
* up to the parent's implementation.</para>
|
|
* <para>If a #ClutterConstraint is parametrized - i.e. if it contains
|
|
* properties that affect the way the constraint is implemented - it should
|
|
* call clutter_actor_queue_relayout() on the actor to which it is attached
|
|
* to whenever any parameter is changed. The actor to which it is attached
|
|
* can be recovered at any point using clutter_actor_meta_get_actor().</para>
|
|
* </refsect2>
|
|
*
|
|
* #ClutterConstraint is available since Clutter 1.4
|
|
*/
|
|
|
|
#ifdef HAVE_CONFIG_H
|
|
#include "config.h"
|
|
#endif
|
|
|
|
#include "clutter-constraint.h"
|
|
|
|
#include "clutter-actor.h"
|
|
#include "clutter-actor-meta-private.h"
|
|
|
|
G_DEFINE_ABSTRACT_TYPE (ClutterConstraint,
|
|
clutter_constraint,
|
|
CLUTTER_TYPE_ACTOR_META);
|
|
|
|
static void
|
|
constraint_update_allocation (ClutterConstraint *constraint,
|
|
ClutterActor *actor,
|
|
ClutterActorBox *allocation)
|
|
{
|
|
}
|
|
|
|
static void
|
|
clutter_constraint_class_init (ClutterConstraintClass *klass)
|
|
{
|
|
klass->update_allocation = constraint_update_allocation;
|
|
}
|
|
|
|
static void
|
|
clutter_constraint_init (ClutterConstraint *self)
|
|
{
|
|
}
|
|
|
|
void
|
|
_clutter_constraint_update_allocation (ClutterConstraint *constraint,
|
|
ClutterActor *actor,
|
|
ClutterActorBox *allocation)
|
|
{
|
|
g_return_if_fail (CLUTTER_IS_CONSTRAINT (constraint));
|
|
g_return_if_fail (CLUTTER_IS_ACTOR (actor));
|
|
g_return_if_fail (allocation != NULL);
|
|
|
|
CLUTTER_CONSTRAINT_GET_CLASS (constraint)->update_allocation (constraint,
|
|
actor,
|
|
allocation);
|
|
}
|