c444447cd3
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.
121 lines
4.0 KiB
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121 lines
4.0 KiB
XML
<?xml version="1.0"?>
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<!DOCTYPE chapter PUBLIC
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"-//OASIS//DTD DocBook XML V4.3//EN"
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"http://www.oasis-open.org/docbook/xml/4.3/docbookx.dtd" [
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]>
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<chapter id="migrating-ClutterBehaviour">
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<chapterinfo>
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<author>
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<firstname>Emmanuele</firstname>
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<surname>Bassi</surname>
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<affiliation>
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<address>
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<email>ebassi@linux.intel.com</email>
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</address>
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</affiliation>
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</author>
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</chapterinfo>
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<title>Migrating from ClutterBehaviour</title>
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<para>The #ClutterBehaviour class and its sub-classes have been deprecated
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since Clutter 1.6. The animation framework provided by #ClutterAnimation,
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#ClutterAnimator and #ClutterState fully replaces all functionality from the
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#ClutterBehaviour classes.</para>
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<para>Generally, animations using #ClutterBehaviour sub-classes can be
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effectively re-implemented just by using #ClutterActor properties.</para>
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<para>Here is an example of an animation using a
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#ClutterBehaviourOpacity instance:</para>
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<informalexample>
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<programlisting>
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ClutterTimeline *timeline = clutter_timeline_new (250);
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ClutterAlpha *alpha = clutter_alpha_new_full (timeline, CLUTTER_LINEAR);
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ClutterBehaviour *behaviour = clutter_behaviour_opacity_new (alpha, 255, 0);
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clutter_behaviour_apply (behaviour, some_actor);
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clutter_timeline_start (timeline);
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</programlisting>
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</informalexample>
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<para>The same effect can be achieved by using clutter_actor_animate() and
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the #ClutterActor:opacity property:</para>
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<informalexample>
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<programlisting>
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clutter_actor_set_opacity (some_actor, 255);
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clutter_actor_animate (some_actor, CLUTTER_LINEAR, 250,
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"opacity", 0,
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NULL);
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</programlisting>
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</informalexample>
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<para>#ClutterBehaviour<!-- -->s used for continuous animations with looping
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timelines can still be effectively replaced by looping animations; for
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instance, the following example of a "pulsating" actor using
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#ClutterBehaviourScale:</para>
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<informalexample>
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<programlisting>
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static void
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reverse_timeline (ClutterTimeline *timeline)
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{
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ClutterTimelineDirection dir = clutter_timeline_get_direction (timeline);
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if (dir == CLUTTER_TIMELINE_FORWARD)
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dir = CLUTTER_TIMELINE_BACKWARD;
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else
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dir = CLUTTER_TIMELINE_FORWARD;
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clutter_timeline_set_direction (timeline, dir);
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}
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ClutterTimeline *timeline = clutter_timeline_new (500);
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ClutterAlpha *alpha = clutter_alpha_new_full (timeline, CLUTTER_LINEAR);
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ClutterBehaviour *behaviour;
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g_object_set (some_actor, "scale-gravity", CLUTTER_GRAVITY_CENTER, NULL);
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behaviour = clutter_behaviour_scale_new (alpha,
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1.0, 2.0,
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1.0, 2.0);
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clutter_behaviour_apply (behaviour, some_actor);
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g_signal_connect (timeline,
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"completed", G_CALLBACK (reverse_timeline),
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NULL);
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clutter_timeline_set_loop (timeline);
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clutter_timeline_start (timeline);
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</programlisting>
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</informalexample>
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<para>The same effect can be achieved using a #ClutterAnimation:</para>
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<informalexample>
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<programlisting>
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ClutterAnimation *animation =
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clutter_actor_animate (some_actor, CLUTTER_LINEAR, 500,
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"scale-x", 2.0,
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"scale-y", 2.0,
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"fixed::scale-gravity", CLUTTER_GRAVITY_CENTER,
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NULL);
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ClutterTimeline *timeline = clutter_animation_get_timeline (animation);
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clutter_timeline_set_loop (timeline, TRUE);
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clutter_timeline_set_auto_reverse (timeline, TRUE);
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</programlisting>
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</informalexample>
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<para>#ClutterBehaviour sub-classes can be applied to multiple actors, in
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order to share the duration and the easing mode. It is possible to use the
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same underlying #ClutterTimeline and #ClutterAlpha instances with
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#ClutterAnimation to achieve the same effect. Complex animations, spanning
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multiple actors, should use the #ClutterAnimator and #ClutterState classes
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instead.</para>
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</chapter>
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