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mutter-performance-source/clutter/clutter/clutter-action.h
Jonas Dreßler 63cc4da4f9 clutter/gesture: Cancel other gestures when moving to RECOGNIZING
Quite often there are situations where multiple gestures try to
recognize, keeping track of the same set of points (for example an edge
drag gesture on the stage and a click gesture somewhere in the
scenegraph). Usually what's wanted here is that the first gesture to
move to RECOGNIZING wins over all other active gestures and "claims" the
point for itself.

We implement this by introducing a concept called "influencing". It
works by making all gestures operating on a shared set of points aware
of each other using ClutterAction->register_sequence().
ClutterGesture uses this vfunc to keep track of all other
ClutterGestures that are potentially conflicting, and keeps a list
(priv->cancel_on_recognizing) of those. As soon as the move to
RECOGNIZING happens, all gestures inside this list get moved to
CANCELLED.

To allow fine-grained control over this behavior, two APIs are
introduced:

1) on the implementation level (should_influence() and
should_be_influenced_by()): This is a vfunc that gets called as soon as
a potential conflict is detected. It's helpful when a specific gesture
always behaves the same towards another gesture, for example to make
sure a LongPress gesture never cancels a DragGesture.

2) on the gesture user level, clutter_gesture_can_not_cancel() is
introduced: This allows control for the user of a gesture to specify
that a specific instance of a gesture won't cancel another gesture.
Calling this twice so that both gestures can't cancel each other allows
for things like simultaneous recognition of a pinch-to-zoom and rotate
gesture.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2389>
2024-03-15 00:07:59 +01:00

99 lines
3.6 KiB
C

/*
* Clutter.
*
* An OpenGL based 'interactive canvas' library.
*
* Copyright (C) 2010 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/>.
*
* Author:
* Emmanuele Bassi <ebassi@linux.intel.com>
*/
#pragma once
#if !defined(__CLUTTER_H_INSIDE__) && !defined(CLUTTER_COMPILATION)
#error "Only <clutter/clutter.h> can be included directly."
#endif
#include "clutter/clutter-actor-meta.h"
G_BEGIN_DECLS
#define CLUTTER_TYPE_ACTION (clutter_action_get_type ())
CLUTTER_EXPORT
G_DECLARE_DERIVABLE_TYPE (ClutterAction, clutter_action,
CLUTTER, ACTION, ClutterActorMeta);
/**
* ClutterActionClass:
*
* The ClutterActionClass structure contains only private data
*/
struct _ClutterActionClass
{
/*< private >*/
ClutterActorMetaClass parent_class;
gboolean (* handle_event) (ClutterAction *action,
const ClutterEvent *event);
void (* sequence_cancelled) (ClutterAction *action,
ClutterInputDevice *device,
ClutterEventSequence *sequence);
gboolean (* register_sequence) (ClutterAction *self,
const ClutterEvent *event);
int (* setup_sequence_relationship) (ClutterAction *action_1,
ClutterAction *action_2,
ClutterInputDevice *device,
ClutterEventSequence *sequence);
};
/* ClutterActor API */
CLUTTER_EXPORT
void clutter_actor_add_action (ClutterActor *self,
ClutterAction *action);
CLUTTER_EXPORT
void clutter_actor_add_action_with_name (ClutterActor *self,
const gchar *name,
ClutterAction *action);
CLUTTER_EXPORT
void clutter_actor_add_action_full (ClutterActor *self,
const char *name,
ClutterEventPhase phase,
ClutterAction *action);
CLUTTER_EXPORT
void clutter_actor_remove_action (ClutterActor *self,
ClutterAction *action);
CLUTTER_EXPORT
void clutter_actor_remove_action_by_name (ClutterActor *self,
const gchar *name);
CLUTTER_EXPORT
ClutterAction *clutter_actor_get_action (ClutterActor *self,
const gchar *name);
CLUTTER_EXPORT
GList * clutter_actor_get_actions (ClutterActor *self);
CLUTTER_EXPORT
void clutter_actor_clear_actions (ClutterActor *self);
CLUTTER_EXPORT
gboolean clutter_actor_has_actions (ClutterActor *self);
ClutterEventPhase clutter_action_get_phase (ClutterAction *action);
G_END_DECLS