2008-02-15 Emmanuele Bassi <ebassi@openedhand.com>
* clutter-animation.sgml: Fix the animations documentation.
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Emmanuele Bassi
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@ -1,8 +1,10 @@
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2008-02-15 Emmanuele Bassi <ebassi@openedhand.com>
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* clutter-animation.sgml: Fix the animations documentation.
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2008-02-15 Chris Lord <chris@openedhand.com>
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reviewed by: <delete if not using a buddy>
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* clutter-docs.sgml:
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* clutter-docs.sgml: Fix documentation.
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2008-02-15 Matthew Allum <mallum@openedhand.com>
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@ -87,89 +87,109 @@ rotate_actor (gpointer data)
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<section id="clutter-animation-timelines">
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<title>Timelines</title>
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<para>
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Clutter Timelines abstract a set period of time with a set rate at
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which to call a provided call back function.
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#ClutterTimeline<!-- -->s abstract a set period of time with a set frame
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rate at which to call a provided callback.
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</para>
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<para>
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They essentially extend g_timeout like functionality further by;
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#ClutterTimeline<!-- -->s also extend the timeout sources functionality
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further by:
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</para>
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<orderedlist>
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<listitem><para>Having a set duration (in milliseconds) and a set 'frame rate'. Essentially the rate at which the callback is called.</para></listitem>
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<listitem><para>Passing current position information to the callback.</para></listitem>
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<listitem><para>Handling 'dropped frames' in guarenteeing the set duration and skipping over frames if Clutter cannot keep up with set rates.</para></listitem>
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<listitem><para>Query the number of milliseconds elapsed between current and previous callback.</para></listitem>
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<listitem><para>Allowing the timeline to be modified on the fly as well as being stoped, started, looped, rewound, reversed.</para></listitem>
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<listitem><para>Using the ClutterTimeoutPool to more efficiently schedule multiple timeout istances.</para></listitem>
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<listitem><para>Having a set duration (in milliseconds) and a set
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'frame rate' - that is, the rate at which the callback is
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called</para></listitem>
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<listitem><para>Passing current progress information to the
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callback</para></listitem>
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<listitem><para>Handling 'dropped frames' and guarenteeing the set
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duration by skipping over frames if the callback cannot keep up with
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the set frame rate</para></listitem>
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<listitem><para>Querying the number of milliseconds elapsed between
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the current and previous callback.</para></listitem>
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<listitem><para>Allowing the timeline to be modified on the fly as
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well as being stopped, started, looped, rewound and
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reversed</para></listitem>
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<listitem><para>Using a #ClutterTimeoutPool to more efficiently
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schedule multiple timeout sources without incurring in potential
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starvation of the main loop slices</para></listitem>
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</orderedlist>
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<para>
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A Timeline is created with;
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</para>
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<programlisting>
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clutter_timeline_new (guint n_frames, guint fps);
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clutter_timeline_new (n_frames, frames_per_seconds);
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</programlisting>
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<para>
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Taking a number of frames and a frames per second, or by;
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</para>
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<programlisting>
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clutter_timeline_new_for_duration (guint msecs);
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clutter_timeline_new_for_duration (msecs);
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</programlisting>
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<para>
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Which takes the duration of the timeline in milliseconds with a
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default frame rate (See #clutter_get_default_frame_rate())
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default frame rate (See clutter_get_default_frame_rate()).
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</para>
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<para>
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The speed, duration and number of frames of the timeline then be
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modifed via the objects properties and API calls. The timeline can
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be made to loop by settings it "loop" property to TRUE.
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be made to loop by settings it "loop" property to %TRUE.
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</para>
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<para>
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The timelines is started via #clutter_timeline_start () and its
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playback further manipulated by the #clutter_timeline_pause (),
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#clutter_timeline_stop (), #clutter_timeline_rewind () ,
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#clutter_timeline_skip () calls.
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The timelines is started via clutter_timeline_start() and its
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playback further manipulated by the clutter_timeline_pause(),
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clutter_timeline_stop(), clutter_timeline_rewind() and
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clutter_timeline_skip() calls.
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</para>
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<para>
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By attaching a handler to the timelines "new-frame" signal a timeline
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can then be used to drive an animation by altering actors visual
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properties in this callback. The callback looks like;
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By attaching a handler to the timeline's ClutterTimeline::new-frame
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signal a timeline can then be used to drive an animation by altering
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an actor's visual properties in this callback. The callback looks like:
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</para>
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<programlisting>
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void on_new_frame (ClutterTimeline *timeline,
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void
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on_new_frame (ClutterTimeline *timeline,
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gint frame_num,
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gpointer user_data)
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{
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}
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</programlisting>
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<para>
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The new-frame signals 'frame_num' parameter is set to the timelines
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current frame number this is between 0 and the "num-frames"
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property. This value can be used to compute the state of a
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particular animation that is dependant on the current timeline
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position. The function #clutter_timeline_get_progress () can also be
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used to get a normalised value of the timelines current position.
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The <literal>frame_num</literal> parameter is set to the timeline's
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current frame number (which is between 0 and the "num-frames" property).
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This value can be used to compute the state of a particular animation
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that is dependant on the frame numer. The clutter_timeline_get_progress()
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function can also be used to get a normalised value of the timeline's
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current position between 0 and 1.
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</para>
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<para>
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Timelines can also be played in reverse
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#clutter_timeline_set_direction() and a one-time delay set before
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they begin playing #clutter_timeline_set_delay ().
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Timelines can also be played in reverse by setting the direction using
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clutter_timeline_set_direction(), and can also have a one-time delay set
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before they begin playing by using clutter_timeline_set_delay().
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</para>
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<para>
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When using a timeline to control a physical simulation using
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#clutter_timeline_get_delta() allows retrieving the number of frames
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and milliseconds since the previous callback to ensure the physics
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simulation to be able to take the actual time elapsed between
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Timelines can also control a pyshical simulation; the
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clutter_timeline_get_delta() function allows retrieving the number of
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frames and milliseconds elapsed since the previous callback to ensure
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the physics engine to be able to take the actual time elapsed between
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iterations into account.
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</para>
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@ -188,9 +208,11 @@ on_new_frame (ClutterTimeline *timeline,
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{
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ClutterActor *actor = CLUTTER_ACTOR(data);
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clutter_actor_set_rotation (actor, (gdouble)frame_num,
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clutter_actor_set_rotation (actor, CLUTTER_Z_AXIS,
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(gdouble) frame_num,
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clutter_actor_get_width (actor) / 2,
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clutter_actor_get_height (actor)/2);
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clutter_actor_get_height (actor) / 2,
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0);
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}
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int
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@ -213,8 +235,8 @@ main (int argc, char *argv[])
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clutter_actor_set_position (actor, 100, 100);
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timeline = clutter_timeline_new (360, 60); /* num frames, fps */
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g_object_set(timeline, "loop", TRUE, NULL); /* have it loop */
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timeline = clutter_timeline_new_for (360, 60); /* a degree per frame */
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clutter_timeline_set_loop (timeline, TRUE);
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g_signal_connect (timeline, "new-frame", G_CALLBACK (on_new_frame), actor);
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@ -266,19 +288,58 @@ main (int argc, char *argv[])
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</para>
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<para>
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%CLUTTER_ALPHA_RAMP_INC
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%CLUTTER_ALPHA_RAMP_DEC
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%CLUTTER_ALPHA_RAMP
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%CLUTTER_ALPHA_SINE
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%CLUTTER_ALPHA_SINE_INC
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%CLUTTER_ALPHA_SINE_DEC
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%CLUTTER_ALPHA_SINE_HALF
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%CLUTTER_ALPHA_SQUARE
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%CLUTTER_ALPHA_SMOOTHSTEP_INC
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%CLUTTER_ALPHA_SMOOTHSTEP_DEC
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%CLUTTER_ALPHA_EXP_INC
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%CLUTTER_ALPHA_EXP_DEC
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<variablelist>
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<varlistentry>
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<term>%CLUTTER_ALPHA_RAMP_INC</term>
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<listitem><simpara>Increasing ramp function</simpara></listitem>
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</varlistentry>
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<varlistentry>
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<term>%CLUTTER_ALPHA_RAMP_DEC</term>
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<listitem><simpara>Decreasing ramp function</simpara></listitem>
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</varlistentry>
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<varlistentry>
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<term>%CLUTTER_ALPHA_RAMP</term>
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<listitem><simpara>Full ramp function</simpara></listitem>
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</varlistentry>
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<varlistentry>
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<term>%CLUTTER_ALPHA_SINE_INC</term>
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<listitem><simpara>Increasing sine function</simpara></listitem>
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</varlistentry>
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<varlistentry>
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<term>%CLUTTER_ALPHA_SINE_DEC</term>
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<listitem><simpara>Decreasing sine function</simpara></listitem>
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</varlistentry>
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<varlistentry>
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<term>%CLUTTER_ALPHA_SINE_HALF</term>
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<listitem><simpara>Half sine function</simpara></listitem>
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</varlistentry>
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<varlistentry>
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<term>%CLUTTER_ALPHA_SINE</term>
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<listitem><simpara>Full sine function</simpara></listitem>
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</varlistentry>
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<varlistentry>
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<term>%CLUTTER_ALPHA_SQUARE</term>
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<listitem><simpara>Square waveform ("step") function</simpara></listitem>
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</varlistentry>
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<varlistentry>
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<term>%CLUTTER_ALPHA_SMOOTHSTEP_INC</term>
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<listitem><simpara>Increasing smooth transition step
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function</simpara></listitem>
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</varlistentry>
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<varlistentry>
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<term>%CLUTTER_ALPHA_SMOOTHSTEP_DEC</term>
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<listitem><simpara>Decreasing smooth transition step
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function</simpara></listitem>
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</varlistentry>
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<varlistentry>
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<term>%CLUTTER_ALPHA_EXP_INC</term>
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<listitem><simpara>Increasing exponential function</simpara></listitem>
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</varlistentry>
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<varlistentry>
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<term>%CLUTTER_ALPHA_EXP_DEC</term>
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<listitem><simpara>Decreasing exponential function</simpara></listitem>
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</varlistentry>
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</variablelist>
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</para>
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<para>
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@ -331,18 +392,42 @@ main (int argc, char *argv[])
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</para>
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<para>
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The behaviours included with clutter are
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The behaviours included in Clutter are
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</para>
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<para>
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#ClutterBehaviourBspline
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#ClutterBehaviourDepth
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#ClutterBehaviourEllipse
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#ClutterBehaviourOpacity
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#ClutterBehaviourPath
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#ClutterBehaviourRotate
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#ClutterBehaviourScale
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<variablelist>
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<varlistentry>
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<term>#ClutterBehaviourBspline</term>
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<listitem><simpara>Moves actors along a B-spline path</simpara></listitem>
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</varlistentry>
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<varlistentry>
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<term>#ClutterBehaviourDepth</term>
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<listitem><simpara>Changes the depth of actors</simpara></listitem>
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</varlistentry>
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<varlistentry>
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<term>#ClutterBehaviourEllipse</term>
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<listitem><simpara>Moves actors along an ellipsis</simpara></listitem>
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</varlistentry>
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<varlistentry>
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<term>#ClutterBehaviourOpacity</term>
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<listitem><simpara>Changes the opacity of actors</simpara></listitem>
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</varlistentry>
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<varlistentry>
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<term>#ClutterBehaviourPath</term>
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<listitem><simpara>Moves actors along a path</simpara></listitem>
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</varlistentry>
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<varlistentry>
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<term>#ClutterBehaviourRotate</term>
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<listitem><simpara>Rotates actors along an axis</simpara></listitem>
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</varlistentry>
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<varlistentry>
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<term>#ClutterBehaviourScale</term>
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<listitem><simpara>Changes the scaling factors of
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actors</simpara></listitem>
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</varlistentry>
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</variablelist>
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</para>
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@ -372,10 +457,10 @@ main (int argc, char *argv[])
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clutter_container_add_actor (CLUTTER_CONTAINER (stage), actor);
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timeline = clutter_timeline_new (100, 26); /* num frames, fps */
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g_object_set(timeline, "loop", TRUE, NULL); /* have it loop */
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timeline = clutter_timeline_new_for_duration (4000); /* milliseconds */
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clutter_timeline_set_loop (timeline, TRUE);
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/* Set an alpha func to power behaviour */
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/* Set an alpha func to power the behaviour */
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alpha = clutter_alpha_new_full (timeline,
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CLUTTER_ALPHA_SINE,
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NULL, NULL);
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@ -386,8 +471,8 @@ main (int argc, char *argv[])
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400, /* width */
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300, /* height */
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CLUTTER_ROTATE_CW, /* direction */
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0.0, /* angle begin */
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360.0); /* angle end */
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0.0, /* initial angle */
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360.0); /* final angle */
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clutter_behaviour_apply (behave, actor);
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@ -397,6 +482,10 @@ main (int argc, char *argv[])
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clutter_main();
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/* clean up */
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g_object_unref (behave);
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g_object_unref (timeline);
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return 0;
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}
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@ -406,18 +495,20 @@ main (int argc, char *argv[])
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<note>Behaviour parameters can be changed whilst a animation is running</note>
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<para>
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There can be many ClutterAlpha's attached to a single timeline. There can be
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many Behaviours for a ClutterAlpha There can be many Behaviours applied to an
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actor. A ClutterScore can be used to chain many behaviour togeather
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There can be many #ClutterAlpha's attached to a single timeline. There
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can be many behaviours for a #ClutterAlpha. There can be many behaviours
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applied to an actor. A #ClutterScore can be used to chain many behaviour
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together.
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</para>
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<warn>combining behaviours that effect the same actor properties
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(i.e two seperate paths) will cause unexpected results. The values
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<warn><para>Combining behaviours that effect the same actor properties
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(i.e two separate paths) will cause unexpected results. The values
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will not be merged in any way with essentially a the last applied
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behaviour taking precedence.</warn>
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behaviour taking precedence.</para></warn>
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<para>
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FIXME: actually move subclassing behaviours here?
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Tips for implementing a new behaviour can be found <link
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linkend="creating-your-own-behaviours">here</link>.
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</para>
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</section>
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@ -426,22 +517,20 @@ behaviour taking precedence.</warn>
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<para>
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ClutterEffect's provide a simplified abstraction for firing simple
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transitions from code. ClutterEffects are created from
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ClutterEffectTemplate s which are an abstraction of a timeline and
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an alpha. An effect template can be created with:
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Clutter effects API provide a simplified abstraction for firing simple
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transitions from code. Clutter effects are created from a
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#ClutterEffectTemplate which is an abstraction of a timeline and
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an alpha function. An effect template can be created with:
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</para>
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<programlisting>
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ClutterEffectTemplate *etemplate;
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etemplate = clutter_effect_template_new_for_duration (
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2000, CLUTTER_ALPHA_RAMP_INC);
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ClutterEffectTemplate *etemplate =
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clutter_effect_template_new_for_duration (2000, CLUTTER_ALPHA_RAMP_INC);
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</programlisting>
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<para>
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This will create an effect template lasting 2000 milliseconds (2
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seconds) and use an alpha function of CLUTTER_ALPHA_RAMP_INC, there
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seconds) and use an alpha function of %CLUTTER_ALPHA_RAMP_INC, there
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are other more advanced forms for creating effect templates from
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existing timelines, as well as attaching a callback to be called
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with user_data when the effect template is destroyed.
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@ -449,32 +538,39 @@ etemplate = clutter_effect_template_new_for_duration (
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</para>
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<para>
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When we have an effect-template we can create a temporary behaviour
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When we have an effect template we can create a temporary behaviour
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animating an actor simply by issuing:
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</para>
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<programlisting>
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clutter_actor_move (etemplate, actor, 23, 42, NULL, NULL);
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clutter_effect_move (etemplate, actor, 23, 42, NULL, NULL);
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</programlisting>
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<para>
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and the actor will move to the coordintes 23, 42 in 2 seconds, if we at the
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same time issued:
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and the actor will move from its current position to the coordinates
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(23, 42) in 2 seconds. Effects can also be stacked, so calling:
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</para>
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<programlisting>
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clutter_actor_fade (etemplate, actor, 0x0, NULL, NULL);
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clutter_effect_move (etemplate, actor, 23, 42, NULL, NULL);
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clutter_effect_fade (etemplate, actor, 0, NULL, NULL);
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</programlisting>
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<para>
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The actor would fade out at the same time.
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The actor will move and fade out at the same time.
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</para>
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<para>
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Clutter effects return a timeline, you can stop an effect from
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Since effects return a #ClutterTimeline, you can stop an effect from
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immediatly happening by calling clutter_timeline_stop () on the
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returned timeline. This returned timeline can also be used to then
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||||
use effects in the ClutterScore etc.
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returned timeline.
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||||
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||||
</para>
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||||
<para>
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||||
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||||
The timeline and all the effect infrastructure is unreferenced as soon
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||||
as the timeline emits the ClutterTimeline::completed signal.
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||||
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||||
</para>
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||||
</section>
|
||||
|
||||
<section id="clutter-animation-conclusion">
|
||||
<title>Conclusion</title>
|
||||
<para>
|
||||
@ -493,7 +589,10 @@ The actor would fade out at the same time.
|
||||
</para>
|
||||
<para>
|
||||
|
||||
The animation functionality in clutter is primarily suited to building animations with a set or finite running time - i.e transitions and the like. For animations involving variable input (such as touchscreen handling) physical simulations may be more suited.
|
||||
The animation functionality in Clutter is primarily suited to
|
||||
building animations with a set or finite running time - i.e transitions
|
||||
and the like. For animations involving variable input (such as touchscreen
|
||||
handling) physical simulations may be more suited.
|
||||
|
||||
</para>
|
||||
|
||||
|
||||
Loading…
Reference in New Issue
Block a user