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cookbook: Use new API to reverse timeline

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clutter_timeline_set_reverse() can be used to
automatically reverse a timeline's direction each time
it completes, so use that in looping animation recipe and
examples.
This commit is contained in:
Elliot Smith 2010-11-30 16:52:01 +00:00
parent 4f17bf3bcc
commit 50849ac1fd
2 changed files with 19 additions and 30 deletions
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25
doc/cookbook/animations.xml
View File

@ -2372,7 +2372,7 @@ clutter_actor_animate_with_timeline (actor,
</programlisting>
</informalexample>
<para>One further technique is to swop the timeline's
<para>One further technique is to repeatedly reverse the timeline's
direction to create a "closed loop" animation (one which returns
to its origin at the end of each iteration). See
<link linkend="animations-looping-discussion-closed-loop">this
@ -2655,12 +2655,23 @@ timeline_completed_cb (ClutterTimeline *timeline,
animations, one the inverse of the other, and chaining them together.</para>
<para>However, a simpler solution is to run forward through the timeline
once; then invert its direction when the end of timeline is reached.
The animation continues, but in reverse. Once the backward iteration
completes, set the timeline to run forward again. Keep changing the
timeline's direction each time it completes. This
is the approach used in <link linkend="animations-looping-example-1">the
example</link>, which results in a smooth, repeated right to left,
once, and have the timeline invert itself when its end is reached.
The animation then continues, but in reverse. Once the backward iteration
completes, the timeline sets itself to run forward again, etc.</para>
<para>To make a timeline reverse its direction each time it
completes, use the <function>clutter_timeline_set_reverse()</function>
function:</para>
<informalexample>
<programlisting>
clutter_timeline_set_reverse (timeline, TRUE);
</programlisting>
</informalexample>
<para>This is the approach used in
<link linkend="animations-looping-example-1">the example</link>,
which results in a smooth, repeated right to left,
left to right motion.</para>
<para>See <link linkend="animations-inversion">this

24
doc/cookbook/examples/animations-looping-implicit.c
View File

@ -10,20 +10,6 @@ typedef struct
ClutterTimeline *timeline;
} State;
static void
invert_timeline_cb (ClutterTimeline *timeline,
gpointer user_data)
{
ClutterTimelineDirection direction = clutter_timeline_get_direction (timeline);
if (direction == CLUTTER_TIMELINE_FORWARD)
direction = CLUTTER_TIMELINE_BACKWARD;
else
direction = CLUTTER_TIMELINE_FORWARD;
clutter_timeline_set_direction (timeline, direction);
}
static gboolean
key_pressed_cb (ClutterActor *actor,
ClutterEvent *event,
@ -63,21 +49,13 @@ main (int argc,
state->timeline = clutter_timeline_new (1000);
clutter_timeline_set_loop (state->timeline, TRUE);
clutter_timeline_set_reverse (state->timeline, TRUE);
g_signal_connect (stage,
"key-press-event",
G_CALLBACK (key_pressed_cb),
state);
/* the animation will not emit a "completed" signal,
* as it is set to loop; but the timeline emits "completed"
* at the end of each iteration of the loop
*/
g_signal_connect (state->timeline,
"completed",
G_CALLBACK (invert_timeline_cb),
NULL);
clutter_container_add_actor (CLUTTER_CONTAINER (stage), state->actor);
clutter_actor_show (stage);