/*
* Clutter.
*
* An OpenGL based 'interactive canvas' library.
*
* Authored By Matthew Allum <mallum@openedhand.com>
* Jorn Baayen <jorn@openedhand.com>
* Emmanuele Bassi <ebassi@openedhand.com>
* Tomas Frydrych <tf@openedhand.com>
*
* Copyright (C) 2006, 2007, 2008 OpenedHand
* Copyright (C) 2009, 2010 Intel Corp.
*
* 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, see <http://www.gnu.org/licenses/>.
*/
/**
* SECTION:clutter-alpha
* @short_description: A class for calculating a value as a function of time
*
* #ClutterAlpha is a class for calculating an floating point value
* dependent only on the position of a #ClutterTimeline.
*
* For newly written code, it is recommended to use the
* #ClutterTimeline:progress-mode property of #ClutterTimeline, or the
* clutter_timeline_set_progress_func() function instead of #ClutterAlpha.
* The #ClutterAlpha class will be deprecated in the future, and will not
* be available any more in the next major version of Clutter.
*
* A #ClutterAlpha binds a #ClutterTimeline to a progress function which
* translates the time T into an adimensional factor alpha. The factor can
* then be used to drive a #ClutterBehaviour, which will translate the
* alpha value into something meaningful for a #ClutterActor.
*
* You should provide a #ClutterTimeline and bind it to the #ClutterAlpha
* instance using clutter_alpha_set_timeline(). You should also set an
* "animation mode", either by using the #ClutterAnimationMode values that
* Clutter itself provides or by registering custom functions using
* clutter_alpha_register_func().
*
* Instead of a #ClutterAnimationMode you may provide a function returning
* the alpha value depending on the progress of the timeline, using
* clutter_alpha_set_func() or clutter_alpha_set_closure(). The alpha
* function will be executed each time a new frame in the #ClutterTimeline
* is reached.
*
* Since the alpha function is controlled by the timeline instance, you can
* pause, stop or resume the #ClutterAlpha from calling the alpha function by
* using the appropriate functions of the #ClutterTimeline object.
*
* #ClutterAlpha is used to "drive" a #ClutterBehaviour instance, and it
* is internally used by the #ClutterAnimation API.
*
* #ClutterAlpha is available since Clutter 0.2.
*
* #ClutterAlpha is deprecated since Clutter 1.12; use #ClutterTimeline and the
* #ClutterTimeline:progress-mode property.
*
* ## ClutterAlpha custom properties for #ClutterScript
*
* #ClutterAlpha defines a custom `function` property for
* #ClutterScript which allows to reference a custom alpha function
* available in the source code. Setting the `function` property
* is equivalent to calling clutter_alpha_set_func() with the
* specified function name. No user data or #GDestroyNotify is
* available to be passed.
*
* The following JSON fragment defines a #ClutterAlpha
* using a #ClutterTimeline with id "sine-timeline" and an alpha
* function called `my_sine_alpha`. The defined #ClutterAlpha
* instance can be reused in multiple #ClutterBehaviour
* definitions or for #ClutterAnimation definitions.
*
* |[
* {
* "id" : "sine-alpha",
* "timeline" : {
* "id" : "sine-timeline",
* "duration" : 500,
* "loop" : true
* },
* "function" : "my_sine_alpha"
* }
* ]|
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <math.h>
#include <gmodule.h>
#define CLUTTER_DISABLE_DEPRECATION_WARNINGS
#include "clutter-alpha.h"
#include "clutter-debug.h"
#include "clutter-enum-types.h"
#include "clutter-easing.h"
#include "clutter-main.h"
#include "clutter-marshal.h"
#include "clutter-private.h"
#include "clutter-scriptable.h"
#include "clutter-script-private.h"
struct _ClutterAlphaPrivate
{
ClutterTimeline *timeline;
guint timeline_new_frame_id;
gdouble alpha;
GClosure *closure;
ClutterAlphaFunc func;
gpointer user_data;
GDestroyNotify notify;
gulong mode;
};
enum
{
PROP_0,
PROP_TIMELINE,
PROP_ALPHA,
PROP_MODE,
PROP_LAST
};
static GParamSpec *obj_props[PROP_LAST];
static void clutter_scriptable_iface_init (ClutterScriptableIface *iface);
G_DEFINE_TYPE_WITH_CODE (ClutterAlpha,
clutter_alpha,
G_TYPE_INITIALLY_UNOWNED,
G_ADD_PRIVATE (ClutterAlpha)
G_IMPLEMENT_INTERFACE (CLUTTER_TYPE_SCRIPTABLE,
clutter_scriptable_iface_init));
static void
timeline_new_frame_cb (ClutterTimeline *timeline,
guint msecs,
ClutterAlpha *alpha)
{
ClutterAlphaPrivate *priv = alpha->priv;
/* Update alpha value and notify */
priv->alpha = clutter_alpha_get_alpha (alpha);
g_object_notify_by_pspec (G_OBJECT (alpha), obj_props[PROP_ALPHA]);
}
static void
clutter_alpha_set_property (GObject *object,
guint prop_id,
const GValue *value,
GParamSpec *pspec)
{
ClutterAlpha *alpha = CLUTTER_ALPHA (object);
switch (prop_id)
{
case PROP_TIMELINE:
clutter_alpha_set_timeline (alpha, g_value_get_object (value));
break;
case PROP_MODE:
clutter_alpha_set_mode (alpha, g_value_get_ulong (value));
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static void
clutter_alpha_get_property (GObject *object,
guint prop_id,
GValue *value,
GParamSpec *pspec)
{
ClutterAlphaPrivate *priv = CLUTTER_ALPHA (object)->priv;
switch (prop_id)
{
case PROP_TIMELINE:
g_value_set_object (value, priv->timeline);
break;
case PROP_ALPHA:
g_value_set_double (value, priv->alpha);
break;
case PROP_MODE:
g_value_set_ulong (value, priv->mode);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static void
clutter_alpha_finalize (GObject *object)
{
ClutterAlphaPrivate *priv = CLUTTER_ALPHA (object)->priv;
if (priv->notify != NULL)
priv->notify (priv->user_data);
else if (priv->closure != NULL)
g_closure_unref (priv->closure);
G_OBJECT_CLASS (clutter_alpha_parent_class)->finalize (object);
}
static void
clutter_alpha_dispose (GObject *object)
{
ClutterAlpha *self = CLUTTER_ALPHA(object);
clutter_alpha_set_timeline (self, NULL);
G_OBJECT_CLASS (clutter_alpha_parent_class)->dispose (object);
}
static ClutterAlphaFunc
resolve_alpha_func (const gchar *name)
{
static GModule *module = NULL;
ClutterAlphaFunc func;
CLUTTER_NOTE (SCRIPT, "Looking up '%s' alpha function", name);
if (G_UNLIKELY (module == NULL))
module = g_module_open (NULL, 0);
if (g_module_symbol (module, name, (gpointer) &func))
{
CLUTTER_NOTE (SCRIPT, "Found '%s' alpha function in the symbols table",
name);
return func;
}
return NULL;
}
static void
clutter_alpha_set_custom_property (ClutterScriptable *scriptable,
ClutterScript *script,
const gchar *name,
const GValue *value)
{
if (strncmp (name, "function", 8) == 0)
{
g_assert (G_VALUE_HOLDS (value, G_TYPE_POINTER));
if (g_value_get_pointer (value) != NULL)
{
clutter_alpha_set_func (CLUTTER_ALPHA (scriptable),
g_value_get_pointer (value),
NULL, NULL);
}
}
else
g_object_set_property (G_OBJECT (scriptable), name, value);
}
static gboolean
clutter_alpha_parse_custom_node (ClutterScriptable *scriptable,
ClutterScript *script,
GValue *value,
const gchar *name,
JsonNode *node)
{
if (strncmp (name, "function", 8) == 0)
{
const gchar *func_name = json_node_get_string (node);
g_value_init (value, G_TYPE_POINTER);
g_value_set_pointer (value, resolve_alpha_func (func_name));
return TRUE;
}
/* we need to do this because we use gulong in place
* of ClutterAnimationMode for ClutterAlpha:mode
*/
if (strncmp (name, "mode", 4) == 0)
{
gulong mode;
mode = _clutter_script_resolve_animation_mode (node);
g_value_init (value, G_TYPE_ULONG);
g_value_set_ulong (value, mode);
return TRUE;
}
return FALSE;
}
static void
clutter_scriptable_iface_init (ClutterScriptableIface *iface)
{
iface->parse_custom_node = clutter_alpha_parse_custom_node;
iface->set_custom_property = clutter_alpha_set_custom_property;
}
static void
clutter_alpha_class_init (ClutterAlphaClass *klass)
{
GObjectClass *object_class = G_OBJECT_CLASS (klass);
object_class->set_property = clutter_alpha_set_property;
object_class->get_property = clutter_alpha_get_property;
object_class->finalize = clutter_alpha_finalize;
object_class->dispose = clutter_alpha_dispose;
/**
* ClutterAlpha:timeline:
*
* A #ClutterTimeline instance used to drive the alpha function.
*
* Since: 0.2
*
* Deprecated: 1.12
*/
obj_props[PROP_TIMELINE] =
g_param_spec_object ("timeline",
P_("Timeline"),
P_("Timeline used by the alpha"),
CLUTTER_TYPE_TIMELINE,
CLUTTER_PARAM_READWRITE);
/**
* ClutterAlpha:alpha:
*
* The alpha value as computed by the alpha function. The linear
* interval is 0.0 to 1.0, but the Alpha allows overshooting by
* one unit in each direction, so the valid interval is -1.0 to 2.0.
*
* Since: 0.2
* Deprecated: 1.12
*/
obj_props[PROP_ALPHA] =
g_param_spec_double ("alpha",
P_("Alpha value"),
P_("Alpha value as computed by the alpha"),
-1.0, 2.0,
0.0,
CLUTTER_PARAM_READABLE);
/**
* ClutterAlpha:mode:
*
* The progress function logical id - either a value from the
* #ClutterAnimationMode enumeration or a value returned by
* clutter_alpha_register_func().
*
* If %CLUTTER_CUSTOM_MODE is used then the function set using
* clutter_alpha_set_closure() or clutter_alpha_set_func()
* will be used.
*
* Since: 1.0
* Deprecated: 1.12
*/
obj_props[PROP_MODE] =
g_param_spec_ulong ("mode",
P_("Mode"),
P_("Progress mode"),
0, G_MAXULONG,
CLUTTER_CUSTOM_MODE,
G_PARAM_CONSTRUCT | CLUTTER_PARAM_READWRITE);
g_object_class_install_properties (object_class,
PROP_LAST,
obj_props);
}
static void
clutter_alpha_init (ClutterAlpha *self)
{
self->priv = clutter_alpha_get_instance_private (self);
self->priv->mode = CLUTTER_CUSTOM_MODE;
self->priv->alpha = 0.0;
}
/**
* clutter_alpha_get_alpha:
* @alpha: A #ClutterAlpha
*
* Query the current alpha value.
*
* Return Value: The current alpha value for the alpha
*
* Since: 0.2
*
* Deprecated: 1.12
*/
gdouble
clutter_alpha_get_alpha (ClutterAlpha *alpha)
{
ClutterAlphaPrivate *priv;
gdouble retval = 0;
g_return_val_if_fail (CLUTTER_IS_ALPHA (alpha), 0);
priv = alpha->priv;
if (G_LIKELY (priv->func))
{
return priv->func (alpha, priv->user_data);
}
else if (priv->closure)
{
GValue params = G_VALUE_INIT;
GValue result_value = G_VALUE_INIT;
g_object_ref (alpha);
g_value_init (&result_value, G_TYPE_DOUBLE);
g_value_init (¶ms, CLUTTER_TYPE_ALPHA);
g_value_set_object (¶ms, alpha);
g_closure_invoke (priv->closure, &result_value, 1, ¶ms, NULL);
retval = g_value_get_double (&result_value);
g_value_unset (&result_value);
g_value_unset (¶ms);
g_object_unref (alpha);
}
return retval;
}
/*
* clutter_alpha_set_closure_internal:
* @alpha: a #ClutterAlpha
* @closure: a #GClosure
*
* Sets the @closure for @alpha. This function does not
* set the #ClutterAlpha:mode property and does not emit
* the #GObject::notify signal for it.
*/
static inline void
clutter_alpha_set_closure_internal (ClutterAlpha *alpha,
GClosure *closure)
{
ClutterAlphaPrivate *priv = alpha->priv;
if (priv->notify != NULL)
priv->notify (priv->user_data);
else if (priv->closure != NULL)
g_closure_unref (priv->closure);
priv->func = NULL;
priv->user_data = NULL;
priv->notify = NULL;
if (closure == NULL)
return;
/* need to take ownership of the closure before sinking it */
priv->closure = g_closure_ref (closure);
g_closure_sink (closure);
/* set the marshaller */
if (G_CLOSURE_NEEDS_MARSHAL (closure))
{
GClosureMarshal marshal = _clutter_marshal_DOUBLE__VOID;
g_closure_set_marshal (priv->closure, marshal);
}
}
/**
* clutter_alpha_set_closure:
* @alpha: A #ClutterAlpha
* @closure: A #GClosure
*
* Sets the #GClosure used to compute the alpha value at each
* frame of the #ClutterTimeline bound to @alpha.
*
* Since: 0.8
*
* Deprecated: 1.12
*/
void
clutter_alpha_set_closure (ClutterAlpha *alpha,
GClosure *closure)
{
ClutterAlphaPrivate *priv;
g_return_if_fail (CLUTTER_IS_ALPHA (alpha));
g_return_if_fail (closure != NULL);
priv = alpha->priv;
clutter_alpha_set_closure_internal (alpha, closure);
priv->mode = CLUTTER_CUSTOM_MODE;
g_object_notify_by_pspec (G_OBJECT (alpha), obj_props[PROP_MODE]);
}
/**
* clutter_alpha_set_func:
* @alpha: A #ClutterAlpha
* @func: A #ClutterAlphaFunc
* @data: user data to be passed to the alpha function, or %NULL
* @destroy: notify function used when disposing the alpha function
*
* Sets the #ClutterAlphaFunc function used to compute
* the alpha value at each frame of the #ClutterTimeline
* bound to @alpha.
*
* This function will not register @func as a global alpha function.
*
* Since: 0.2
*
* Deprecated: 1.12
*/
void
clutter_alpha_set_func (ClutterAlpha *alpha,
ClutterAlphaFunc func,
gpointer data,
GDestroyNotify destroy)
{
ClutterAlphaPrivate *priv;
g_return_if_fail (CLUTTER_IS_ALPHA (alpha));
g_return_if_fail (func != NULL);
priv = alpha->priv;
if (priv->notify != NULL)
{
priv->notify (priv->user_data);
}
else if (priv->closure != NULL)
{
g_closure_unref (priv->closure);
priv->closure = NULL;
}
priv->func = func;
priv->user_data = data;
priv->notify = destroy;
priv->mode = CLUTTER_CUSTOM_MODE;
g_object_notify_by_pspec (G_OBJECT (alpha), obj_props[PROP_MODE]);
}
/**
* clutter_alpha_set_timeline:
* @alpha: A #ClutterAlpha
* @timeline: A #ClutterTimeline
*
* Binds @alpha to @timeline.
*
* Since: 0.2
*
* Deprecated: 1.12
*/
void
clutter_alpha_set_timeline (ClutterAlpha *alpha,
ClutterTimeline *timeline)
{
ClutterAlphaPrivate *priv;
g_return_if_fail (CLUTTER_IS_ALPHA (alpha));
g_return_if_fail (timeline == NULL || CLUTTER_IS_TIMELINE (timeline));
priv = alpha->priv;
if (priv->timeline == timeline)
return;
if (priv->timeline)
{
g_signal_handlers_disconnect_by_func (priv->timeline,
timeline_new_frame_cb,
alpha);
g_object_unref (priv->timeline);
priv->timeline = NULL;
}
if (timeline)
{
priv->timeline = g_object_ref (timeline);
g_signal_connect (priv->timeline, "new-frame",
G_CALLBACK (timeline_new_frame_cb),
alpha);
}
g_object_notify_by_pspec (G_OBJECT (alpha), obj_props[PROP_TIMELINE]);
}
/**
* clutter_alpha_get_timeline:
* @alpha: A #ClutterAlpha
*
* Gets the #ClutterTimeline bound to @alpha.
*
* Return value: (transfer none): a #ClutterTimeline instance
*
* Since: 0.2
*
* Deprecated: 1.12
*/
ClutterTimeline *
clutter_alpha_get_timeline (ClutterAlpha *alpha)
{
g_return_val_if_fail (CLUTTER_IS_ALPHA (alpha), NULL);
return alpha->priv->timeline;
}
/**
* clutter_alpha_new:
*
* Creates a new #ClutterAlpha instance. You must set a function
* to compute the alpha value using clutter_alpha_set_func() and
* bind a #ClutterTimeline object to the #ClutterAlpha instance
* using clutter_alpha_set_timeline().
*
* You should use the newly created #ClutterAlpha instance inside
* a #ClutterBehaviour object.
*
* Return value: the newly created empty #ClutterAlpha instance.
*
* Since: 0.2
*
* Deprecated: 1.12
*/
ClutterAlpha *
clutter_alpha_new (void)
{
return g_object_new (CLUTTER_TYPE_ALPHA, NULL);
}
/**
* clutter_alpha_new_full:
* @timeline: #ClutterTimeline timeline
* @mode: animation mode
*
* Creates a new #ClutterAlpha instance and sets the timeline
* and animation mode.
*
* See also clutter_alpha_set_timeline() and clutter_alpha_set_mode().
*
* Return Value: the newly created #ClutterAlpha
*
* Since: 1.0
*
* Deprecated: 1.12
*/
ClutterAlpha *
clutter_alpha_new_full (ClutterTimeline *timeline,
gulong mode)
{
g_return_val_if_fail (CLUTTER_IS_TIMELINE (timeline), NULL);
g_return_val_if_fail (mode != CLUTTER_ANIMATION_LAST, NULL);
return g_object_new (CLUTTER_TYPE_ALPHA,
"timeline", timeline,
"mode", mode,
NULL);
}
/**
* clutter_alpha_new_with_func:
* @timeline: a #ClutterTimeline
* @func: a #ClutterAlphaFunc
* @data: data to pass to the function, or %NULL
* @destroy: function to call when removing the alpha function, or %NULL
*
* Creates a new #ClutterAlpha instances and sets the timeline
* and the alpha function.
*
* This function will not register @func as a global alpha function.
*
* See also clutter_alpha_set_timeline() and clutter_alpha_set_func().
*
* Return value: the newly created #ClutterAlpha
*
* Since: 1.0
*
* Deprecated: 1.12
*/
ClutterAlpha *
clutter_alpha_new_with_func (ClutterTimeline *timeline,
ClutterAlphaFunc func,
gpointer data,
GDestroyNotify destroy)
{
ClutterAlpha *retval;
g_return_val_if_fail (CLUTTER_IS_TIMELINE (timeline), NULL);
g_return_val_if_fail (func != NULL, NULL);
retval = clutter_alpha_new ();
clutter_alpha_set_timeline (retval, timeline);
clutter_alpha_set_func (retval, func, data, destroy);
return retval;
}
/**
* clutter_alpha_get_mode:
* @alpha: a #ClutterAlpha
*
* Retrieves the #ClutterAnimationMode used by @alpha.
*
* Return value: the animation mode
*
* Since: 1.0
*
* Deprecated: 1.12
*/
gulong
clutter_alpha_get_mode (ClutterAlpha *alpha)
{
g_return_val_if_fail (CLUTTER_IS_ALPHA (alpha), CLUTTER_CUSTOM_MODE);
return alpha->priv->mode;
}
typedef struct _AlphaData {
guint closure_set : 1;
ClutterAlphaFunc func;
gpointer data;
GClosure *closure;
} AlphaData;
static GPtrArray *clutter_alphas = NULL;
static gdouble
clutter_alpha_easing_func (ClutterAlpha *alpha,
gpointer data G_GNUC_UNUSED)
{
ClutterAlphaPrivate *priv = alpha->priv;
ClutterTimeline *timeline = priv->timeline;
gdouble t, d;
if (G_UNLIKELY (priv->timeline == NULL))
return 0.0;
t = clutter_timeline_get_elapsed_time (timeline);
d = clutter_timeline_get_duration (timeline);
return clutter_easing_for_mode (priv->mode, t, d);
}
/**
* clutter_alpha_set_mode:
* @alpha: a #ClutterAlpha
* @mode: a #ClutterAnimationMode
*
* Sets the progress function of @alpha using the symbolic value
* of @mode, as taken by the #ClutterAnimationMode enumeration or
* using the value returned by clutter_alpha_register_func().
*
* Since: 1.0
*
* Deprecated: 1.12
*/
void
clutter_alpha_set_mode (ClutterAlpha *alpha,
gulong mode)
{
ClutterAlphaPrivate *priv;
g_return_if_fail (CLUTTER_IS_ALPHA (alpha));
g_return_if_fail (mode != CLUTTER_ANIMATION_LAST);
priv = alpha->priv;
if (mode == CLUTTER_CUSTOM_MODE)
{
priv->mode = mode;
}
else if (mode < CLUTTER_ANIMATION_LAST)
{
if (priv->mode == mode)
return;
/* sanity check to avoid getting an out of sync
* enum/function mapping
*/
g_assert (clutter_get_easing_func_for_mode (mode) != NULL);
clutter_alpha_set_closure_internal (alpha, NULL);
priv->mode = mode;
CLUTTER_NOTE (ANIMATION, "New easing mode '%s'[%lu]\n",
clutter_get_easing_name_for_mode (priv->mode),
priv->mode);
priv->func = clutter_alpha_easing_func;
priv->user_data = NULL;
priv->notify = NULL;
}
else if (mode > CLUTTER_ANIMATION_LAST)
{
AlphaData *alpha_data = NULL;
gulong real_index = 0;
if (priv->mode == mode)
return;
if (G_UNLIKELY (clutter_alphas == NULL))
{
g_warning ("No alpha functions defined for ClutterAlpha to use. "
"Use clutter_alpha_register_func() to register an "
"alpha function.");
return;
}
real_index = mode - CLUTTER_ANIMATION_LAST - 1;
alpha_data = g_ptr_array_index (clutter_alphas, real_index);
if (G_UNLIKELY (alpha_data == NULL))
{
g_warning ("No alpha function registered for mode %lu.",
mode);
return;
}
if (alpha_data->closure_set)
clutter_alpha_set_closure (alpha, alpha_data->closure);
else
{
clutter_alpha_set_closure_internal (alpha, NULL);
priv->func = alpha_data->func;
priv->user_data = alpha_data->data;
priv->notify = NULL;
}
priv->mode = mode;
}
else
g_assert_not_reached ();
g_object_notify_by_pspec (G_OBJECT (alpha), obj_props[PROP_MODE]);
}
static gulong
register_alpha_internal (AlphaData *alpha_data)
{
if (G_UNLIKELY (clutter_alphas == NULL))
clutter_alphas = g_ptr_array_new ();
g_ptr_array_add (clutter_alphas, alpha_data);
return clutter_alphas->len + CLUTTER_ANIMATION_LAST;
}
/**
* clutter_alpha_register_func: (skip)
* @func: a #ClutterAlphaFunc
* @data: user data to pass to @func, or %NULL
*
* Registers a global alpha function and returns its logical id
* to be used by clutter_alpha_set_mode() or by #ClutterAnimation.
*
* The logical id is always greater than %CLUTTER_ANIMATION_LAST.
*
* Return value: the logical id of the alpha function
*
* Since: 1.0
*
* Deprecated: 1.12
*/
gulong
clutter_alpha_register_func (ClutterAlphaFunc func,
gpointer data)
{
AlphaData *alpha_data;
g_return_val_if_fail (func != NULL, 0);
alpha_data = g_slice_new (AlphaData);
alpha_data->closure_set = FALSE;
alpha_data->func = func;
alpha_data->data = data;
return register_alpha_internal (alpha_data);
}
/**
* clutter_alpha_register_closure:
* @closure: a #GClosure
*
* #GClosure variant of clutter_alpha_register_func().
*
* Registers a global alpha function and returns its logical id
* to be used by clutter_alpha_set_mode() or by #ClutterAnimation.
*
* The logical id is always greater than %CLUTTER_ANIMATION_LAST.
*
* Rename to: clutter_alpha_register_func
*
* Return value: the logical id of the alpha function
*
* Since: 1.0
*
* Deprecated: 1.12
*/
gulong
clutter_alpha_register_closure (GClosure *closure)
{
AlphaData *alpha_data;
g_return_val_if_fail (closure != NULL, 0);
alpha_data = g_slice_new (AlphaData);
alpha_data->closure_set = TRUE;
alpha_data->closure = closure;
return register_alpha_internal (alpha_data);
}