mutter/doc/reference/clutter/migrating-ClutterBehaviour.xml
Emmanuele Bassi c444447cd3 timeline: Rename the reverse property to auto-reverse
Other frameworks expose the same functionality as "auto-reverse",
probably to match the cassette tape player. It actually makes sense
for Clutter to follow suit.
2010-12-17 12:07:52 +00:00

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<?xml version="1.0"?>
<!DOCTYPE chapter PUBLIC
"-//OASIS//DTD DocBook XML V4.3//EN"
"http://www.oasis-open.org/docbook/xml/4.3/docbookx.dtd" [
]>
<chapter id="migrating-ClutterBehaviour">
<chapterinfo>
<author>
<firstname>Emmanuele</firstname>
<surname>Bassi</surname>
<affiliation>
<address>
<email>ebassi@linux.intel.com</email>
</address>
</affiliation>
</author>
</chapterinfo>
<title>Migrating from ClutterBehaviour</title>
<para>The #ClutterBehaviour class and its sub-classes have been deprecated
since Clutter 1.6. The animation framework provided by #ClutterAnimation,
#ClutterAnimator and #ClutterState fully replaces all functionality from the
#ClutterBehaviour classes.</para>
<para>Generally, animations using #ClutterBehaviour sub-classes can be
effectively re-implemented just by using #ClutterActor properties.</para>
<para>Here is an example of an animation using a
#ClutterBehaviourOpacity instance:</para>
<informalexample>
<programlisting>
ClutterTimeline *timeline = clutter_timeline_new (250);
ClutterAlpha *alpha = clutter_alpha_new_full (timeline, CLUTTER_LINEAR);
ClutterBehaviour *behaviour = clutter_behaviour_opacity_new (alpha, 255, 0);
clutter_behaviour_apply (behaviour, some_actor);
clutter_timeline_start (timeline);
</programlisting>
</informalexample>
<para>The same effect can be achieved by using clutter_actor_animate() and
the #ClutterActor:opacity property:</para>
<informalexample>
<programlisting>
clutter_actor_set_opacity (some_actor, 255);
clutter_actor_animate (some_actor, CLUTTER_LINEAR, 250,
"opacity", 0,
NULL);
</programlisting>
</informalexample>
<para>#ClutterBehaviour<!-- -->s used for continuous animations with looping
timelines can still be effectively replaced by looping animations; for
instance, the following example of a "pulsating" actor using
#ClutterBehaviourScale:</para>
<informalexample>
<programlisting>
static void
reverse_timeline (ClutterTimeline *timeline)
{
ClutterTimelineDirection dir = clutter_timeline_get_direction (timeline);
if (dir == CLUTTER_TIMELINE_FORWARD)
dir = CLUTTER_TIMELINE_BACKWARD;
else
dir = CLUTTER_TIMELINE_FORWARD;
clutter_timeline_set_direction (timeline, dir);
}
ClutterTimeline *timeline = clutter_timeline_new (500);
ClutterAlpha *alpha = clutter_alpha_new_full (timeline, CLUTTER_LINEAR);
ClutterBehaviour *behaviour;
g_object_set (some_actor, "scale-gravity", CLUTTER_GRAVITY_CENTER, NULL);
behaviour = clutter_behaviour_scale_new (alpha,
1.0, 2.0,
1.0, 2.0);
clutter_behaviour_apply (behaviour, some_actor);
g_signal_connect (timeline,
"completed", G_CALLBACK (reverse_timeline),
NULL);
clutter_timeline_set_loop (timeline);
clutter_timeline_start (timeline);
</programlisting>
</informalexample>
<para>The same effect can be achieved using a #ClutterAnimation:</para>
<informalexample>
<programlisting>
ClutterAnimation *animation =
clutter_actor_animate (some_actor, CLUTTER_LINEAR, 500,
"scale-x", 2.0,
"scale-y", 2.0,
"fixed::scale-gravity", CLUTTER_GRAVITY_CENTER,
NULL);
ClutterTimeline *timeline = clutter_animation_get_timeline (animation);
clutter_timeline_set_loop (timeline, TRUE);
clutter_timeline_set_auto_reverse (timeline, TRUE);
</programlisting>
</informalexample>
<para>#ClutterBehaviour sub-classes can be applied to multiple actors, in
order to share the duration and the easing mode. It is possible to use the
same underlying #ClutterTimeline and #ClutterAlpha instances with
#ClutterAnimation to achieve the same effect. Complex animations, spanning
multiple actors, should use the #ClutterAnimator and #ClutterState classes
instead.</para>
</chapter>