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mutter-performance-source/clutter/clutter-behaviour-opacity.c
Emmanuele Bassi 7d7372af43 [animation] Move the alpha value to floating point 
The current Alpha value is an unsigned integer that can be used
implicitly as a fixed point value. This makes writing an alpha
function overshooting below and above the current range basically
impossible without complicating an already complex code, and
creating weird corner cases.

For this reason, the Alpha value should be defined as a floating
point normalized value, spanning a range between 0.0 and 1.0; in
order to allow overshooting, the valid range is extended one unit
below and one unit above, thus making it -1.0 .. 2.0.

This commit updates the various users of the ClutterAlpha API
and the tests cases.

This commit also removes all the current alpha functions exposed
in the public API.
2009-01-20 16:42:49 +00:00

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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-opacity
* @short_description: A behaviour controlling opacity
*
* #ClutterBehaviourPath interpolates actors opacity between two values.
*
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "clutter-actor.h"
#include "clutter-behaviour.h"
#include "clutter-behaviour-opacity.h"
#include "clutter-enum-types.h"
#include "clutter-main.h"
#include "clutter-private.h"
#include "clutter-debug.h"
#include <math.h>
/**
* SECTION:clutter-behaviour-opacity
* @short_description: Behaviour controlling the opacity
*
* #ClutterBehaviourOpacity controls the opacity of a set of actors.
*
* Since: 0.2
*/
G_DEFINE_TYPE (ClutterBehaviourOpacity,
clutter_behaviour_opacity,
CLUTTER_TYPE_BEHAVIOUR);
struct _ClutterBehaviourOpacityPrivate
{
guint8 opacity_start;
guint8 opacity_end;
};
#define CLUTTER_BEHAVIOUR_OPACITY_GET_PRIVATE(obj) \
(G_TYPE_INSTANCE_GET_PRIVATE ((obj), \
CLUTTER_TYPE_BEHAVIOUR_OPACITY, \
ClutterBehaviourOpacityPrivate))
enum
{
PROP_0,
PROP_OPACITY_START,
PROP_OPACITY_END
};
static void
alpha_notify_foreach (ClutterBehaviour *behaviour,
ClutterActor *actor,
gpointer data)
{
clutter_actor_set_opacity (actor, GPOINTER_TO_UINT(data));
}
static void
clutter_behaviour_alpha_notify (ClutterBehaviour *behave,
gdouble alpha_value)
{
ClutterBehaviourOpacityPrivate *priv;
guint8 opacity;
priv = CLUTTER_BEHAVIOUR_OPACITY (behave)->priv;
opacity = alpha_value
* (priv->opacity_end - priv->opacity_start)
+ priv->opacity_start;
CLUTTER_NOTE (BEHAVIOUR, "alpha: %.4f, opacity: %u",
alpha_value,
opacity);
clutter_behaviour_actors_foreach (behave,
alpha_notify_foreach,
GUINT_TO_POINTER ((guint) opacity));
}
static void
clutter_behaviour_opacity_set_property (GObject *gobject,
guint prop_id,
const GValue *value,
GParamSpec *pspec)
{
ClutterBehaviourOpacity *opacityb = CLUTTER_BEHAVIOUR_OPACITY (gobject);
switch (prop_id)
{
case PROP_OPACITY_START:
opacityb->priv->opacity_start = g_value_get_uint (value);
break;
case PROP_OPACITY_END:
opacityb->priv->opacity_end = g_value_get_uint (value);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (gobject, prop_id, pspec);
break;
}
}
static void
clutter_behaviour_opacity_get_property (GObject *gobject,
guint prop_id,
GValue *value,
GParamSpec *pspec)
{
ClutterBehaviourOpacity *opacityb = CLUTTER_BEHAVIOUR_OPACITY (gobject);
switch (prop_id)
{
case PROP_OPACITY_START:
g_value_set_uint (value, opacityb->priv->opacity_start);
break;
case PROP_OPACITY_END:
g_value_set_uint (value, opacityb->priv->opacity_end);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (gobject, prop_id, pspec);
break;
}
}
static void
clutter_behaviour_opacity_class_init (ClutterBehaviourOpacityClass *klass)
{
GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
ClutterBehaviourClass *behave_class = CLUTTER_BEHAVIOUR_CLASS (klass);
gobject_class->set_property = clutter_behaviour_opacity_set_property;
gobject_class->get_property = clutter_behaviour_opacity_get_property;
/**
* ClutterBehaviourOpacity:opacity-start:
*
* Initial opacity level of the behaviour.
*
* Since: 0.2
*/
g_object_class_install_property (gobject_class,
PROP_OPACITY_START,
g_param_spec_uint ("opacity-start",
"Opacity Start",
"Initial opacity level",
0, 255,
0,
CLUTTER_PARAM_READWRITE));
/**
* ClutterBehaviourOpacity:opacity-end:
*
* Final opacity level of the behaviour.
*
* Since: 0.2
*/
g_object_class_install_property (gobject_class,
PROP_OPACITY_END,
g_param_spec_uint ("opacity-end",
"Opacity End",
"Final opacity level",
0, 255,
0,
CLUTTER_PARAM_READWRITE));
behave_class->alpha_notify = clutter_behaviour_alpha_notify;
g_type_class_add_private (klass, sizeof (ClutterBehaviourOpacityPrivate));
}
static void
clutter_behaviour_opacity_init (ClutterBehaviourOpacity *self)
{
self->priv = CLUTTER_BEHAVIOUR_OPACITY_GET_PRIVATE (self);
self->priv->opacity_start = 0;
self->priv->opacity_end = 0;
}
/**
* clutter_behaviour_opacity_new:
* @alpha: a #ClutterAlpha instance, or %NULL
* @opacity_start: minimum level of opacity
* @opacity_end: maximum level of opacity
*
* Creates a new #ClutterBehaviourOpacity object, driven by @alpha
* which controls the opacity property of every actor, making it
* change in the interval between @opacity_start and @opacity_end.
*
* Return value: the newly created #ClutterBehaviourOpacity
*
* Since: 0.2
*/
ClutterBehaviour *
clutter_behaviour_opacity_new (ClutterAlpha *alpha,
guint8 opacity_start,
guint8 opacity_end)
{
return g_object_new (CLUTTER_TYPE_BEHAVIOUR_OPACITY,
"alpha", alpha,
"opacity-start", opacity_start,
"opacity-end", opacity_end,
NULL);
}
/**
* clutter_behaviour_opacity_set_bounds:
* @behaviour: a #ClutterBehaviourOpacity
* @opacity_start: minimum level of opacity
* @opacity_end: maximum level of opacity
*
* Sets the initial and final levels of the opacity applied by @behaviour
* on each actor it controls.
*
* Since: 0.6
*/
void
clutter_behaviour_opacity_set_bounds (ClutterBehaviourOpacity *behaviour,
guint8 opacity_start,
guint8 opacity_end)
{
ClutterBehaviourOpacityPrivate *priv;
g_return_if_fail (CLUTTER_IS_BEHAVIOUR_OPACITY (behaviour));
priv = behaviour->priv;
g_object_freeze_notify (G_OBJECT (behaviour));
if (priv->opacity_start != opacity_start)
{
priv->opacity_start = opacity_start;
g_object_notify (G_OBJECT (behaviour), "opacity-start");
}
if (priv->opacity_end != opacity_end)
{
priv->opacity_end = opacity_end;
g_object_notify (G_OBJECT (behaviour), "opacity-end");
}
g_object_thaw_notify (G_OBJECT (behaviour));
}
/**
* clutter_behaviour_opacity_get_bounds:
* @behaviour: a #ClutterBehaviourOpacity
* @opacity_start: return location for the minimum level of opacity, or %NULL
* @opacity_end: return location for the maximum level of opacity, or %NULL
*
* Gets the initial and final levels of the opacity applied by @behaviour
* on each actor it controls.
*
* Since: 0.6
*/
void
clutter_behaviour_opacity_get_bounds (ClutterBehaviourOpacity *behaviour,
guint8 *opacity_start,
guint8 *opacity_end)
{
g_return_if_fail (CLUTTER_IS_BEHAVIOUR_OPACITY (behaviour));
if (opacity_start)
*opacity_start = behaviour->priv->opacity_start;
if (opacity_end)
*opacity_end = behaviour->priv->opacity_end;
}
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