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mutter-performance-source/clutter/clutter-alpha.h
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

132 lines
4.8 KiB
C

/*
* 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 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/>.
*/
#if !defined(__CLUTTER_H_INSIDE__) && !defined(CLUTTER_COMPILATION)
#error "Only <clutter/clutter.h> can be included directly."
#endif
#ifndef __CLUTTER_ALPHA_H__
#define __CLUTTER_ALPHA_H__
#include <clutter/clutter-timeline.h>
#include <clutter/clutter-types.h>
G_BEGIN_DECLS
#define CLUTTER_TYPE_ALPHA (clutter_alpha_get_type ())
#define CLUTTER_ALPHA(obj) (G_TYPE_CHECK_INSTANCE_CAST ((obj), CLUTTER_TYPE_ALPHA, ClutterAlpha))
#define CLUTTER_ALPHA_CLASS(klass) (G_TYPE_CHECK_CLASS_CAST ((klass), CLUTTER_TYPE_ALPHA, ClutterAlphaClass))
#define CLUTTER_IS_ALPHA(obj) (G_TYPE_CHECK_INSTANCE_TYPE ((obj), CLUTTER_TYPE_ALPHA))
#define CLUTTER_IS_ALPHA_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE ((klass), CLUTTER_TYPE_ALPHA))
#define CLUTTER_ALPHA_GET_CLASS(obj) (G_TYPE_INSTANCE_GET_CLASS ((obj), CLUTTER_TYPE_ALPHA, ClutterAlphaClass))
typedef struct _ClutterAlpha ClutterAlpha;
typedef struct _ClutterAlphaClass ClutterAlphaClass;
typedef struct _ClutterAlphaPrivate ClutterAlphaPrivate;
/**
* ClutterAlphaFunc:
* @alpha: a #ClutterAlpha
* @user_data: user data passed to the function
*
* A function returning a value depending on the position of
* the #ClutterTimeline bound to @alpha.
*
* Return value: a floating point value
*
* Since: 0.2
*/
typedef gdouble (*ClutterAlphaFunc) (ClutterAlpha *alpha,
gpointer user_data);
/**
* ClutterAlpha:
*
* #ClutterAlpha combines a #ClutterTimeline and a function.
* The contents of the #ClutterAlpha structure are private and should
* only be accessed using the provided API.
*
* Since: 0.2
*/
struct _ClutterAlpha
{
/*< private >*/
GInitiallyUnowned parent;
ClutterAlphaPrivate *priv;
};
/**
* ClutterAlphaClass:
*
* Base class for #ClutterAlpha
*
* Since: 0.2
*/
struct _ClutterAlphaClass
{
/*< private >*/
GInitiallyUnownedClass parent_class;
void (*_clutter_alpha_1) (void);
void (*_clutter_alpha_2) (void);
void (*_clutter_alpha_3) (void);
void (*_clutter_alpha_4) (void);
void (*_clutter_alpha_5) (void);
};
GType clutter_alpha_get_type (void) G_GNUC_CONST;
ClutterAlpha * clutter_alpha_new (void);
ClutterAlpha * clutter_alpha_new_full (ClutterTimeline *timeline,
gulong mode);
ClutterAlpha * clutter_alpha_new_with_func (ClutterTimeline *timeline,
ClutterAlphaFunc func,
gpointer data,
GDestroyNotify destroy);
gdouble clutter_alpha_get_alpha (ClutterAlpha *alpha);
void clutter_alpha_set_func (ClutterAlpha *alpha,
ClutterAlphaFunc func,
gpointer data,
GDestroyNotify destroy);
void clutter_alpha_set_closure (ClutterAlpha *alpha,
GClosure *closure);
void clutter_alpha_set_timeline (ClutterAlpha *alpha,
ClutterTimeline *timeline);
ClutterTimeline *clutter_alpha_get_timeline (ClutterAlpha *alpha);
void clutter_alpha_set_mode (ClutterAlpha *alpha,
gulong mode);
gulong clutter_alpha_get_mode (ClutterAlpha *alpha);
gulong clutter_alpha_register_func (ClutterAlphaFunc func,
gpointer data);
gulong clutter_alpha_register_closure (GClosure *closure);
G_END_DECLS
#endif /* __CLUTTER_ALPHA_H__ */