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Clutter 0.8.2 Reference Manual | |
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ClutterBehaviour;
ClutterBehaviourClass;
void clutter_behaviour_apply (ClutterBehaviour *behave,
ClutterActor *actor);
void clutter_behaviour_remove (ClutterBehaviour *behave,
ClutterActor *actor);
void clutter_behaviour_remove_all (ClutterBehaviour *behave);
gboolean clutter_behaviour_is_applied (ClutterBehaviour *behave,
ClutterActor *actor);
void (*ClutterBehaviourForeachFunc) (ClutterBehaviour *behaviour,
ClutterActor *actor,
gpointer data);
void clutter_behaviour_actors_foreach (ClutterBehaviour *behave,
ClutterBehaviourForeachFunc func,
gpointer data);
GSList* clutter_behaviour_get_actors (ClutterBehaviour *behave);
gint clutter_behaviour_get_n_actors (ClutterBehaviour *behave);
ClutterActor* clutter_behaviour_get_nth_actor (ClutterBehaviour *behave,
gint index_);
ClutterAlpha* clutter_behaviour_get_alpha (ClutterBehaviour *behave);
void clutter_behaviour_set_alpha (ClutterBehaviour *behave,
ClutterAlpha *alpha);
GObject +----ClutterBehaviour +----ClutterBehaviourBspline +----ClutterBehaviourDepth +----ClutterBehaviourEllipse +----ClutterBehaviourOpacity +----ClutterBehaviourPath +----ClutterBehaviourRotate +----ClutterBehaviourScale
ClutterBehaviour is the base class for implementing behaviours. A behaviour is a controller object for ClutterActors; you can use a behaviour to control one or more properties of an actor (such as its opacity, or its position). A ClutterBehaviour is driven by an "alpha function" stored inside a ClutterAlpha object; an alpha function is a function depending solely on time. The alpha function computes a value which is then applied to the properties of the actors driven by a behaviour.
Clutter provides some pre-defined behaviours, like ClutterBehaviourPath, which controls the position of a set of actors making them "walk" along a set of nodes; ClutterBehaviourOpacity, which controls the opacity of a set of actors; ClutterBehaviourScale, which controls the width and height of a set of actors.
To visualize the effects of different alpha functions on a ClutterBehaviour implementation it is possible to take the ClutterBehaviourPath as an example:
The actors position between the path's end points directly correlates
to the ClutterAlpha's current alpha value driving the behaviour. With
the ClutterAlpha's function set to CLUTTER_ALPHA_RAMP_INC the actor
will follow the path at a constant velocity, but when changing to
CLUTTER_ALPHA_SINE_INC the actor initially accelerates before quickly
decelerating.
In order to implement a new behaviour you should subclass ClutterBehaviour and override the "alpha_notify" virtual function; inside the overridden function you should obtain the alpha value from the ClutterAlpha instance bound to the behaviour and apply it to the desiderd property (or properties) of every actor controlled by the behaviour.
ClutterBehaviour is available since Clutter 0.2
typedef struct _ClutterBehaviour ClutterBehaviour;
ClutterBehaviour contains only private data and should be accessed with the functions below.
Since 0.2
typedef struct {
/* vfunc, not signal */
void (*alpha_notify) (ClutterBehaviour *behave,
guint32 alpha_value);
/* signals */
void (*applied) (ClutterBehaviour *behave,
ClutterActor *actor);
void (*removed) (ClutterBehaviour *behave,
ClutterActor *actor);
} ClutterBehaviourClass;
Base class for behaviours.
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virtual function, called each time the ClutterAlpha computes a new alpha value; the actors to which the behaviour applies should be changed in this function. Every subclass of ClutterBehaviour must implement this virtual function |
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signal class handler for the ClutterBehaviour::applied signal |
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signal class handler for the ClutterBehaviour::removed signal |
Since 0.2
void clutter_behaviour_apply (ClutterBehaviour *behave, ClutterActor *actor);
Applies behave to actor. This function adds a reference on
the actor.
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a ClutterBehaviour |
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a ClutterActor |
Since 0.2
void clutter_behaviour_remove (ClutterBehaviour *behave, ClutterActor *actor);
Removes actor from the list of ClutterActors to which
behave applies. This function removes a reference on the actor.
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a ClutterBehaviour |
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a ClutterActor |
Since 0.2
void clutter_behaviour_remove_all (ClutterBehaviour *behave);
Removes every actor from the list that behave holds.
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a ClutterBehaviour |
Since 0.4
gboolean clutter_behaviour_is_applied (ClutterBehaviour *behave, ClutterActor *actor);
Check if behave applied to actor.
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a ClutterBehaviour |
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a ClutterActor |
Returns : |
TRUE if actor has behaviour. FALSE otherwise. |
Since 0.4
void (*ClutterBehaviourForeachFunc) (ClutterBehaviour *behaviour, ClutterActor *actor, gpointer data);
This function is passed to clutter_behaviour_foreach_actor() and
will be called for each actor driven by behaviour.
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the ClutterBehaviour |
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an actor driven by behaviour
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optional data passed to the function |
Since 0.2
void clutter_behaviour_actors_foreach (ClutterBehaviour *behave, ClutterBehaviourForeachFunc func, gpointer data);
Calls func for every actor driven by behave.
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a ClutterBehaviour |
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a function called for each actor |
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optional data to be passed to the function, or NULL
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Since 0.2
GSList* clutter_behaviour_get_actors (ClutterBehaviour *behave);
Retrieves all the actors to which behave applies. It is not recommended
for derived classes to use this in there alpha notify method but use
clutter_behaviour_actors_foreach as it avoids alot of needless allocations.
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a ClutterBehaviour |
Returns : |
a list of actors. You should free the returned list
with g_slist_free() when finished using it.
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Since 0.2
gint clutter_behaviour_get_n_actors (ClutterBehaviour *behave);
Gets the number of actors this behaviour is applied too.
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a ClutterBehaviour |
Returns : |
The number of applied actors |
Since 0.2
ClutterActor* clutter_behaviour_get_nth_actor (ClutterBehaviour *behave, gint index_);
Gets an actor the behaviour was applied to referenced by index num.
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a ClutterBehaviour |
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the index of an actor this behaviour is applied too. |
Returns : |
A Clutter actor or NULL if index_ is invalid.
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Since 0.2
ClutterAlpha* clutter_behaviour_get_alpha (ClutterBehaviour *behave);
Retrieves the ClutterAlpha object bound to behave.
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a ClutterBehaviour |
Returns : |
a ClutterAlpha object, or NULL if no alpha
object has been bound to this behaviour.
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Since 0.2
void clutter_behaviour_set_alpha (ClutterBehaviour *behave, ClutterAlpha *alpha);
Binds alpha to a ClutterBehaviour. The ClutterAlpha object
is what makes a behaviour work: for each tick of the timeline
used by ClutterAlpha a new value of the alpha parameter is
computed by the alpha function; the value should be used by
the ClutterBehaviour to update one or more properties of the
actors to which the behaviour applies.
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a ClutterBehaviour |
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a ClutterAlpha or NULL to unset a previously set alpha
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Since 0.2
"alpha" property"alpha" ClutterAlpha* : Read / Write
The ClutterAlpha object used to drive this behaviour. A ClutterAlpha object binds a ClutterTimeline and a function which computes a value (the "alpha") depending on the time. Each time the alpha value changes the alpha-notify virtual function is called.
Since 0.2
"applied" signalvoid user_function (ClutterBehaviour *behaviour, ClutterActor *actor, gpointer user_data) : Run First
The ::apply signal is emitted each time the behaviour is applied to an actor.
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the ClutterBehaviour that received the signal |
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the actor the behaviour was applied to. |
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user data set when the signal handler was connected. |
Since 0.4
"removed" signalvoid user_function (ClutterBehaviour *behaviour, ClutterActor *actor, gpointer user_data) : Run First
The ::removed signal is emitted each time a behaviour is not applied to an actor anymore.
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the ClutterBehaviour that received the signal |
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the removed actor |
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user data set when the signal handler was connected. |