mutter/clutter/clutter-behaviour-opacity.c
Emmanuele Bassi 588c4504a1 Handle opacity inversion in ClutterBehaviourOpacity
Always make sure that the opacity is a positive integer, even if the
start and end opacities are inverted.

Also, use the correct integer-to-pointer casts, as the opacity is an
unsigned integer.
2007-07-09 21:39:03 +00:00

238 lines
7.2 KiB
C

/*
* 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 class interpolating actors opacity between
* two values.
*
* #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,
guint32 alpha_value)
{
ClutterBehaviourOpacityPrivate *priv;
guint8 delta, opacity;
priv = CLUTTER_BEHAVIOUR_OPACITY (behave)->priv;
if (priv->opacity_end > priv->opacity_start)
delta = priv->opacity_end - priv->opacity_start;
else
delta = priv->opacity_start - priv->opacity_end;
opacity = alpha_value * delta / CLUTTER_ALPHA_MAX_ALPHA;
opacity += ((priv->opacity_end > priv->opacity_start) ? priv->opacity_start
: priv->opacity_end);
CLUTTER_NOTE (BEHAVIOUR, "alpha: %i, opacity: %i", 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 |
G_PARAM_CONSTRUCT));
/**
* 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 |
G_PARAM_CONSTRUCT));
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);
}
/**
* 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);
}