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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-ClutterEffect">
<chapterinfo>
<author>
<firstname>Emmanuele</firstname>
<surname>Bassi</surname>
<affiliation>
<address>
<email>ebassi@linux.intel.com</email>
</address>
</affiliation>
</author>
</chapterinfo>
<title>Migrating from ClutterEffect</title>
<para>Since version 1.0, Clutter provides the #ClutterAnimation API
and the clutter_actor_animate() family of functions as replacements
for the <structname>ClutterEffectTemplate</structname> and
clutter_effect_* API for creating simple, one-off animations.</para>
<section id="using-actor-animate">
<title>Using <function>clutter_actor_animate()</function></title>
<para>Prior to Clutter 1.0, the way to create simple, one-off
animations involving a single actor was the ClutterEffect API. The
major downside of this API was that to abstract the duration and
easing function of the animation the application developer had to
create a <structname>ClutterEffectTemplate</structname> and keep it
around for the duration of the application.</para>
<para>The clutter_actor_animate() function performs all of the
memory management that was delegated to the
<structname>ClutterEffectTemplate</structname>, freeing the developer
from having to deal with object bookkeeping.</para>
<para>Another downside of the ClutterEffect API is that every
possible animation has its own function (scaling, opacity, rotation,
movement, etc.), and new functions cannot be added outside of
Clutter.</para>
<example id="example-clutter-effect">
<title>Effect example</title>
<para>The following code shows a simple animation using
the ClutterEffect API. It animates an actor linearly in 500
milliseconds, by moving it to the (100, 100) coordinates
while fading it out.</para>
<programlisting>
ClutterEffectTemplate *tmpl;
tmpl = clutter_effect_template_new_for_duration (500, clutter_ramp_inc_func);
clutter_effect_move (tmpl, actor, 100, 100, NULL, NULL);
clutter_effect_fade (tmpl, actor, 0, NULL, NULL);
g_object_unref (tmpl);
</programlisting>
</example>
<para>The clutter_actor_animate() function will implicitely
create a #ClutterAnimation with the passed duration and easing
mode, and will bind all the passed properties. All readable and
writable properties specified by a #ClutterActor are animatable
through clutter_actor_animate().</para>
<example id="example-actor-animate">
<title>Animation example</title>
<para>The following code shows the clutter_actor_animate() call
equivalent to the previous ClutterEffect example.</para>
<programlisting>
clutter_actor_animate (actor, CLUTTER_LINEAR, 500,
"x", 100.0,
"y", 100.0,
"opacity", 0,
NULL);
</programlisting>
</example>
<para>The ClutterEffect API provided a way to be notified of the
effect completion. Since the clutter_actor_animate() function creates
a #ClutterAnimation instance it's possible to use the
#ClutterAnimation::completed signal for the same notification.</para>
<example id="example-clutter-effect-complete">
<title>Effect complete example</title>
<para>The following code shows how to receive notification of the
completion of the animation.</para>
<programlisting>
static void
on_fade_complete (ClutterActor *actor,
gpointer data)
{
clutter_actor_hide (actor);
}
ClutterEffectTemplate *tmpl;
tmpl = clutter_effect_template_new_for_duration (500, clutter_ramp_inc_func);
clutter_effect_fade (tmpl, actor, 0, on_fade_complete, NULL);
g_object_unref (tmpl);
</programlisting>
</example>
<para>The clutter_actor_animate() function also has a convenience
wrapper that allows to inline the signal connection:</para>
<example id="example-actor-animate-complete">
<title>Animation completed example</title>
<para>The following code shows how to get the same notification
as the example above.</para>
<programlisting>
ClutterAnimation *animation;
animation = clutter_actor_animate (actor, CLUTTER_LINEAR, 500,
"opacity", 0,
NULL);
g_signal_connect_swapped (animation,
"completed", G_CALLBACK (clutter_actor_hide),
actor);
/* OR */
clutter_actor_animate (actor, CLUTTER_LINEAR, 500,
"opacity", 0,
"signal-swapped::completed", clutter_actor_hide, actor,
NULL);
</programlisting>
</example>
</section>
</chapter>
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