mutter/clutter/clutter-flatten-effect.c
Neil Roberts 701440efd8 clutter-actor: Add a 'has_overlaps' virtual
This adds a virtual to ClutterActor so that an actor subclass can
report whether it has overlapping primitives. ClutterActor uses this
to determine whether it needs to use ClutterFlattenEffect to implement
the opacity property. The default implementation of the virtual
returns TRUE which means that most actors will end up being redirected
offscreen when the opacity != 255. ClutterTexture and ClutterRectangle
override this to return FALSE because they should never need to be
redirected. ClutterClone overrides it to divert to the source.

The values for the ClutterOffscreenRedirect enum have changed to:

AUTOMATIC_FOR_OPACITY

 The actor will only be redirected if has_overlaps returns TRUE and
 the opacity is < 255

ALWAYS_FOR_OPACITY

 The actor will always be redirected if the opacity < 255 regardless
 of the return value of has_overlaps

ALWAYS

 The actor will always be redirected offscreen.

This means that the property can't be used to prevent the actor from
being redirected but only to increase the likelihood that it will be
redirected.

ClutterActor now adds and removes the flatten effect depending on
whether flattening is needed directly in clutter_actor_paint(). There
are new internal versions of add/remove_effect that don't queue a
redraw. This means that ClutterFlattenEffect is now just a no-op
subclass of ClutterOffscreen. It is only needed because
ClutterOffscreen is abstract. Removing the effect also makes it so
that the cached image will be freed as soon as an actor is repainted
without being flattened.
2011-05-13 01:46:32 +01:00

57 lines
1.6 KiB
C

/*
* Clutter.
*
* An OpenGL based 'interactive canvas' library.
*
* Copyright (C) 2011 Intel Corporation.
*
* 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/>.
*
* Authors:
* Neil Roberts <neil@linux.intel.com>
*/
/* This is an internal-only effect used to implement the
'offscreen-redirect' property of ClutterActor. It doesn't actually
need to do anything on top of the ClutterOffscreenEffect class so
it only exists because that class is abstract */
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "clutter-flatten-effect.h"
#include "clutter-private.h"
#include "clutter-actor-private.h"
G_DEFINE_TYPE (ClutterFlattenEffect,
_clutter_flatten_effect,
CLUTTER_TYPE_OFFSCREEN_EFFECT);
static void
_clutter_flatten_effect_class_init (ClutterFlattenEffectClass *klass)
{
}
static void
_clutter_flatten_effect_init (ClutterFlattenEffect *self)
{
}
ClutterEffect *
_clutter_flatten_effect_new (void)
{
return g_object_new (CLUTTER_TYPE_FLATTEN_EFFECT, NULL);
}