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mutter-performance-source/clutter/clutter-behaviour.c
Emmanuele Bassi 742cc4d95b [docs] Small annotation fixes
2009-09-08 10:21:46 +01:00

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/*
* Clutter.
*
* An OpenGL based 'interactive canvas' library.
*
* Authored By Matthew Allum <mallum@openedhand.com>
*
* Copyright (C) 2006 OpenedHand
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
/**
* SECTION:clutter-behaviour
* @short_description: Class for providing behaviours to actors
*
* #ClutterBehaviour is the base class for implementing behaviours. A
* behaviour is a controller object for #ClutterActor<!-- -->s; 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:
*
* <figure id="behaviour-path-alpha">
* <title>Effects of alpha functions on a path</title>
* <graphic fileref="path-alpha-func.png" format="PNG"/>
* </figure>
*
* 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
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "clutter-main.h"
#include "clutter-actor.h"
#include "clutter-behaviour.h"
#include "clutter-debug.h"
#include "clutter-private.h"
#include "clutter-marshal.h"
/**
* clutter_knot_copy:
* @knot: a #ClutterKnot
*
* Makes an allocated copy of a knot.
*
* Return value: the copied knot.
*
* Since: 0.2
*/
ClutterKnot *
clutter_knot_copy (const ClutterKnot *knot)
{
ClutterKnot *copy;
copy = g_slice_new0 (ClutterKnot);
*copy = *knot;
return copy;
}
/**
* clutter_knot_free:
* @knot: a #ClutterKnot
*
* Frees the memory of an allocated knot.
*
* Since: 0.2
*/
void
clutter_knot_free (ClutterKnot *knot)
{
if (G_LIKELY (knot))
{
g_slice_free (ClutterKnot, knot);
}
}
/**
* clutter_knot_equal:
* @knot_a: First knot
* @knot_b: Second knot
*
* Compares to knot and checks if the point to the same location.
*
* Return value: %TRUE if the knots point to the same location.
*
* Since: 0.2
*/
gboolean
clutter_knot_equal (const ClutterKnot *knot_a,
const ClutterKnot *knot_b)
{
g_return_val_if_fail (knot_a != NULL, FALSE);
g_return_val_if_fail (knot_b != NULL, FALSE);
if (knot_a == knot_b)
return TRUE;
return knot_a->x == knot_b->x && knot_a->y == knot_b->y;
}
GType
clutter_knot_get_type (void)
{
static GType our_type = 0;
if (G_UNLIKELY (!our_type))
{
our_type =
g_boxed_type_register_static (I_("ClutterKnot"),
(GBoxedCopyFunc) clutter_knot_copy,
(GBoxedFreeFunc) clutter_knot_free);
}
return our_type;
}
G_DEFINE_ABSTRACT_TYPE (ClutterBehaviour,
clutter_behaviour,
G_TYPE_OBJECT);
struct _ClutterBehaviourPrivate
{
ClutterAlpha *alpha;
guint notify_id;
GSList *actors;
};
enum
{
PROP_0,
PROP_ALPHA
};
enum {
APPLIED,
REMOVED,
LAST_SIGNAL
};
static guint behave_signals[LAST_SIGNAL] = { 0 };
#define CLUTTER_BEHAVIOUR_GET_PRIVATE(obj) \
(G_TYPE_INSTANCE_GET_PRIVATE ((obj), \
CLUTTER_TYPE_BEHAVIOUR, \
ClutterBehaviourPrivate))
static void
clutter_behaviour_dispose (GObject *gobject)
{
ClutterBehaviour *self = CLUTTER_BEHAVIOUR (gobject);
clutter_behaviour_set_alpha (self, NULL);
clutter_behaviour_remove_all (self);
G_OBJECT_CLASS (clutter_behaviour_parent_class)->dispose (gobject);
}
static void
clutter_behaviour_set_property (GObject *object,
guint prop_id,
const GValue *value,
GParamSpec *pspec)
{
ClutterBehaviour *behaviour = CLUTTER_BEHAVIOUR (object);
switch (prop_id)
{
case PROP_ALPHA:
clutter_behaviour_set_alpha (behaviour, g_value_get_object (value));
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static void
clutter_behaviour_get_property (GObject *object,
guint prop_id,
GValue *value,
GParamSpec *pspec)
{
ClutterBehaviour *behaviour = CLUTTER_BEHAVIOUR (object);
ClutterBehaviourPrivate *priv = behaviour->priv;
switch (prop_id)
{
case PROP_ALPHA:
g_value_set_object (value, priv->alpha);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static void
clutter_behaviour_alpha_notify_unimplemented (ClutterBehaviour *behaviour,
gdouble alpha_value)
{
g_warning ("ClutterBehaviourClass::alpha_notify not implemented for '%s'",
g_type_name (G_TYPE_FROM_INSTANCE (behaviour)));
}
static void
clutter_behaviour_class_init (ClutterBehaviourClass *klass)
{
GObjectClass *object_class = G_OBJECT_CLASS (klass);
object_class->dispose = clutter_behaviour_dispose;
object_class->set_property = clutter_behaviour_set_property;
object_class->get_property = clutter_behaviour_get_property;
/**
* ClutterBehaviour:alpha:
*
* 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
*/
g_object_class_install_property (object_class,
PROP_ALPHA,
g_param_spec_object ("alpha",
"Alpha",
"Alpha Object to drive the behaviour",
CLUTTER_TYPE_ALPHA,
CLUTTER_PARAM_READWRITE));
klass->alpha_notify = clutter_behaviour_alpha_notify_unimplemented;
/**
* ClutterBehaviour::applied:
* @behaviour: the #ClutterBehaviour that received the signal
* @actor: the actor the behaviour was applied to.
*
* The ::apply signal is emitted each time the behaviour is applied
* to an actor.
*
* Since: 0.4
*/
behave_signals[APPLIED] =
g_signal_new ("applied",
G_OBJECT_CLASS_TYPE (object_class),
G_SIGNAL_RUN_FIRST,
G_STRUCT_OFFSET (ClutterBehaviourClass, applied),
NULL, NULL,
clutter_marshal_VOID__OBJECT,
G_TYPE_NONE, 1,
CLUTTER_TYPE_ACTOR);
/**
* ClutterBehaviour::removed:
* @behaviour: the #ClutterBehaviour that received the signal
* @actor: the removed actor
*
* The ::removed signal is emitted each time a behaviour is not applied
* to an actor anymore.
*
*/
behave_signals[REMOVED] =
g_signal_new ("removed",
G_OBJECT_CLASS_TYPE (object_class),
G_SIGNAL_RUN_FIRST,
G_STRUCT_OFFSET (ClutterBehaviourClass, removed),
NULL, NULL,
clutter_marshal_VOID__OBJECT,
G_TYPE_NONE, 1,
CLUTTER_TYPE_ACTOR);
g_type_class_add_private (klass, sizeof (ClutterBehaviourPrivate));
}
static void
clutter_behaviour_init (ClutterBehaviour *self)
{
ClutterBehaviourPrivate *priv;
self->priv = priv = CLUTTER_BEHAVIOUR_GET_PRIVATE (self);
}
static void
remove_actor_on_destroy (ClutterActor *actor,
ClutterBehaviour *behaviour)
{
clutter_behaviour_remove (behaviour, actor);
}
/**
* clutter_behaviour_apply:
* @behave: a #ClutterBehaviour
* @actor: a #ClutterActor
*
* Applies @behave to @actor. This function adds a reference on
* the actor.
*
* Since: 0.2
*/
void
clutter_behaviour_apply (ClutterBehaviour *behave,
ClutterActor *actor)
{
ClutterBehaviourPrivate *priv;
g_return_if_fail (CLUTTER_IS_BEHAVIOUR (behave));
g_return_if_fail (CLUTTER_IS_ACTOR (actor));
priv = behave->priv;
if (g_slist_find (priv->actors, actor))
{
g_warning ("The behaviour of type %s already applies "
"to the actor of type %s",
g_type_name (G_OBJECT_TYPE (behave)),
g_type_name (G_OBJECT_TYPE (actor)));
return;
}
priv->actors = g_slist_append (priv->actors, g_object_ref (actor));
g_signal_connect (actor, "destroy",
G_CALLBACK (remove_actor_on_destroy),
behave);
g_signal_emit (behave, behave_signals[APPLIED], 0, actor);
}
/**
* clutter_behaviour_is_applied:
* @behave: a #ClutterBehaviour
* @actor: a #ClutterActor
*
* Check if @behave applied to @actor.
*
* Return value: TRUE if actor has behaviour. FALSE otherwise.
*
* Since: 0.4
*/
gboolean
clutter_behaviour_is_applied (ClutterBehaviour *behave,
ClutterActor *actor)
{
g_return_val_if_fail (CLUTTER_IS_BEHAVIOUR (behave), FALSE);
g_return_val_if_fail (CLUTTER_IS_ACTOR (actor), FALSE);
return (g_slist_find (behave->priv->actors, actor) != NULL);
}
/**
* clutter_behaviour_remove:
* @behave: a #ClutterBehaviour
* @actor: a #ClutterActor
*
* Removes @actor from the list of #ClutterActor<!-- -->s to which
* @behave applies. This function removes a reference on the actor.
*
* Since: 0.2
*/
void
clutter_behaviour_remove (ClutterBehaviour *behave,
ClutterActor *actor)
{
ClutterBehaviourPrivate *priv;
g_return_if_fail (CLUTTER_IS_BEHAVIOUR (behave));
g_return_if_fail (CLUTTER_IS_ACTOR (actor));
priv = behave->priv;
if (!g_slist_find (priv->actors, actor))
{
g_warning ("The behaviour of type %s is not applied "
"to the actor of type %s",
g_type_name (G_OBJECT_TYPE (behave)),
g_type_name (G_OBJECT_TYPE (actor)));
return;
}
g_signal_handlers_disconnect_by_func (actor,
G_CALLBACK (remove_actor_on_destroy),
behave);
priv->actors = g_slist_remove (priv->actors, actor);
g_signal_emit (behave, behave_signals[REMOVED], 0, actor);
g_object_unref (actor);
}
/**
* clutter_behaviour_get_n_actors:
* @behave: a #ClutterBehaviour
*
* Gets the number of actors this behaviour is applied too.
*
* Return value: The number of applied actors
*
* Since: 0.2
*/
gint
clutter_behaviour_get_n_actors (ClutterBehaviour *behave)
{
g_return_val_if_fail (CLUTTER_IS_BEHAVIOUR (behave), 0);
return g_slist_length (behave->priv->actors);
}
/**
* clutter_behaviour_get_nth_actor:
* @behave: a #ClutterBehaviour
* @index_: the index of an actor this behaviour is applied too.
*
* Gets an actor the behaviour was applied to referenced by index num.
*
* Return value: (transfer none): A Clutter actor or NULL if @index_ is invalid.
*
* Since: 0.2
*/
ClutterActor*
clutter_behaviour_get_nth_actor (ClutterBehaviour *behave,
gint index_)
{
g_return_val_if_fail (CLUTTER_IS_BEHAVIOUR (behave), NULL);
return g_slist_nth_data (behave->priv->actors, index_);
}
/**
* clutter_behaviour_actors_foreach:
* @behave: a #ClutterBehaviour
* @func: a function called for each actor
* @data: optional data to be passed to the function, or %NULL
*
* Calls @func for every actor driven by @behave.
*
* Since: 0.2
*/
void
clutter_behaviour_actors_foreach (ClutterBehaviour *behave,
ClutterBehaviourForeachFunc func,
gpointer data)
{
GSList *l;
g_return_if_fail (CLUTTER_IS_BEHAVIOUR (behave));
g_return_if_fail (func != NULL);
for (l = behave->priv->actors; l != NULL; l = l->next)
{
ClutterActor *actor = l->data;
g_assert (CLUTTER_IS_ACTOR (actor));
func (behave, actor, data);
}
}
/**
* clutter_behaviour_get_alpha:
* @behave: a #ClutterBehaviour
*
* Retrieves the #ClutterAlpha object bound to @behave.
*
* Return value: (transfer none): a #ClutterAlpha object, or %NULL if no alpha
* object has been bound to this behaviour.
*
* Since: 0.2
*/
ClutterAlpha *
clutter_behaviour_get_alpha (ClutterBehaviour *behave)
{
g_return_val_if_fail (CLUTTER_IS_BEHAVIOUR (behave), NULL);
return behave->priv->alpha;
}
static void
notify_cb (GObject *object,
GParamSpec *param_spec,
ClutterBehaviour *behave)
{
ClutterBehaviourClass *klass;
klass = CLUTTER_BEHAVIOUR_GET_CLASS (behave);
CLUTTER_NOTE (BEHAVIOUR, "notify::alpha");
/* no actors, we can stop right here */
if (behave->priv->actors == NULL)
return;
if (klass->alpha_notify)
{
gdouble alpha_value = clutter_alpha_get_alpha (behave->priv->alpha);
CLUTTER_NOTE (BEHAVIOUR, "calling %s::alpha_notify (%p, %.4f)",
g_type_name (G_TYPE_FROM_CLASS (klass)),
behave, alpha_value);
klass->alpha_notify (behave, alpha_value);
}
}
/**
* clutter_behaviour_set_alpha:
* @behave: a #ClutterBehaviour
* @alpha: a #ClutterAlpha or %NULL to unset a previously set 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.
*
* If @alpha is not %NULL, the #ClutterBehaviour will take ownership
* of the #ClutterAlpha instance.
*
* Since: 0.2
*/
void
clutter_behaviour_set_alpha (ClutterBehaviour *behave,
ClutterAlpha *alpha)
{
ClutterBehaviourPrivate *priv;
g_return_if_fail (CLUTTER_IS_BEHAVIOUR (behave));
g_return_if_fail (alpha == NULL || CLUTTER_IS_ALPHA (alpha));
priv = behave->priv;
if (alpha)
g_object_ref_sink (alpha);
if (priv->notify_id)
{
CLUTTER_NOTE (BEHAVIOUR, "removing previous notify-id (%d)",
priv->notify_id);
g_signal_handler_disconnect (priv->alpha, priv->notify_id);
priv->notify_id = 0;
}
if (priv->alpha)
{
CLUTTER_NOTE (BEHAVIOUR, "removing previous alpha object");
g_object_unref (priv->alpha);
priv->alpha = NULL;
}
if (alpha)
{
priv->alpha = alpha;
priv->notify_id = g_signal_connect (priv->alpha, "notify::alpha",
G_CALLBACK(notify_cb),
behave);
CLUTTER_NOTE (BEHAVIOUR, "setting new alpha object (%p, notify:%d)",
priv->alpha, priv->notify_id);
}
}
/**
* clutter_behaviour_get_actors:
* @behave: a #ClutterBehaviour
*
* 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.
*
* Return value: (transfer container) (element-type ClutterActor): a list of
* actors. You should free the returned list with g_slist_free() when
* finished using it.
*
* Since: 0.2
*/
GSList *
clutter_behaviour_get_actors (ClutterBehaviour *behave)
{
ClutterBehaviourPrivate *priv;
GSList *retval, *l;
g_return_val_if_fail (CLUTTER_BEHAVIOUR (behave), NULL);
priv = behave->priv;
retval = NULL;
for (l = priv->actors; l != NULL; l = l->next)
retval = g_slist_prepend (retval, l->data);
return g_slist_reverse (retval);
}
/**
* clutter_behaviour_remove_all:
* @behave: a #ClutterBehaviour
*
* Removes every actor from the list that @behave holds.
*
* Since: 0.4
*/
void
clutter_behaviour_remove_all (ClutterBehaviour *behave)
{
ClutterBehaviourPrivate *priv;
GSList *l;
g_return_if_fail (CLUTTER_IS_BEHAVIOUR (behave));
priv = behave->priv;
for (l = priv->actors; l != NULL; l = l->next)
{
ClutterActor *actor = l->data;
g_signal_emit (behave, behave_signals[REMOVED], 0, actor);
g_signal_handlers_disconnect_by_func (actor,
G_CALLBACK (remove_actor_on_destroy),
behave);
g_object_unref (actor);
}
g_slist_free (priv->actors);
priv->actors = NULL;
}
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