63cc4da4f9
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>
54 lines
1.9 KiB
C
54 lines
1.9 KiB
C
/*
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* Clutter.
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*
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* An OpenGL based 'interactive canvas' library.
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*
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* Copyright (C) 2021 Red Hat Inc.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library. If not, see <http://www.gnu.org/licenses/>.
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*
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* Author:
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* Carlos Garnacho <carlosg@gnome.org>
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*/
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#pragma once
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#if !defined(__CLUTTER_H_INSIDE__) && !defined(CLUTTER_COMPILATION)
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#error "Only <clutter/clutter.h> can be included directly."
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#endif
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#include "clutter/clutter-action.h"
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G_BEGIN_DECLS
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void clutter_action_set_phase (ClutterAction *action,
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ClutterEventPhase phase);
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gboolean clutter_action_handle_event (ClutterAction *action,
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const ClutterEvent *event);
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void clutter_action_sequence_cancelled (ClutterAction *action,
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ClutterInputDevice *device,
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ClutterEventSequence *sequence);
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gboolean clutter_action_register_sequence (ClutterAction *self,
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const ClutterEvent *event);
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int clutter_action_setup_sequence_relationship (ClutterAction *action_1,
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ClutterAction *action_2,
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ClutterInputDevice *device,
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ClutterEventSequence *sequence);
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G_END_DECLS
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