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unity8/plugins/Ubuntu/Gestures/DirectionalDragArea.h
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1/*
2 * Copyright (C) 2013,2014 Canonical, Ltd.
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; version 3.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public License
14 * along with this program. If not, see <http://www.gnu.org/licenses/>.
15 */
17#ifndef DIRECTIONAL_DRAG_AREA_H
18#define DIRECTIONAL_DRAG_AREA_H
20#include <QtQuick/QQuickItem>
21#include "UbuntuGesturesQmlGlobal.h"
22#include "Damper.h"
23#include "Direction.h"
25// lib UbuntuGestures
26#include <Pool.h>
27#include <Timer.h>
29class TouchOwnershipEvent;
30class UnownedTouchEvent;
31class DirectionalDragAreaPrivate;
33/*
34 An area that detects axis-aligned single-finger drag gestures
36 If a drag deviates too much from the components' direction recognition will
37 fail. It will also fail if the drag or flick is too short. E.g. a noisy or
38 fidgety click
40 See doc/DirectionalDragArea.svg
41 */
42class UBUNTUGESTURESQML_EXPORT DirectionalDragArea : public QQuickItem {
43 Q_OBJECT
45 // The direction in which the gesture should move in order to be recognized.
46 Q_PROPERTY(Direction::Type direction READ direction WRITE setDirection NOTIFY directionChanged)
48 // The distance travelled by the finger along the axis specified by
49 // DirectionalDragArea's direction.
50 Q_PROPERTY(qreal distance READ distance NOTIFY distanceChanged)
52 // The distance travelled by the finger along the axis specified by
53 // DirectionalDragArea's direction in scene coordinates
54 Q_PROPERTY(qreal sceneDistance READ sceneDistance NOTIFY sceneDistanceChanged)
56 // Position of the touch point performing the drag relative to this item.
57 Q_PROPERTY(qreal touchX READ touchX NOTIFY touchXChanged)
58 Q_PROPERTY(qreal touchY READ touchY NOTIFY touchYChanged)
60 // Position of the touch point performing the drag, in scene's coordinate system
61 Q_PROPERTY(qreal touchSceneX READ touchSceneX NOTIFY touchSceneXChanged)
62 Q_PROPERTY(qreal touchSceneY READ touchSceneY NOTIFY touchSceneYChanged)
64 // Whether a drag gesture is taking place
65 Q_PROPERTY(bool dragging READ dragging NOTIFY draggingChanged)
67 // Whether the drag area is pressed.
68 Q_PROPERTY(bool pressed READ pressed NOTIFY pressedChanged)
70 // Whether a gesture should be Recognized as soon a touch lands on the area.
71 // With this property enabled it will work pretty much like a MultiPointTouchArea,
72 // just with a different API.
73 //
74 // It's false by default. In most cases you will not want that enabled.
75 Q_PROPERTY(bool immediateRecognition
76 READ immediateRecognition
77 WRITE setImmediateRecognition
78 NOTIFY immediateRecognitionChanged)
80 Q_ENUMS(Direction)
81public:
82 DirectionalDragArea(QQuickItem *parent = 0);
84 Direction::Type direction() const;
85 void setDirection(Direction::Type);
87 qreal distance() const;
88 qreal sceneDistance() const;
90 qreal touchX() const;
91 qreal touchY() const;
93 qreal touchSceneX() const;
94 qreal touchSceneY() const;
96 bool dragging() const;
98 bool pressed() const;
100 bool immediateRecognition() const;
101 void setImmediateRecognition(bool enabled);
103 bool event(QEvent *e) override;
105 /*
106 In qmltests, sequences of touch events are sent all at once, unlike in "real life".
107 Also qmltests might run really slowly, e.g. when run from inside virtual machines.
108 Thus to remove a variable that qmltests cannot really control, namely time, this
109 function removes all constraints that are sensible to elapsed time.
111 This effectively makes the DirectionalDragArea easier to fool.
112 */
113 Q_INVOKABLE void removeTimeConstraints();
115Q_SIGNALS:
116 void directionChanged(Direction::Type direction);
117 void draggingChanged(bool value);
118 void pressedChanged(bool value);
119 void distanceChanged(qreal value);
120 void sceneDistanceChanged(qreal value);
121 void touchXChanged(qreal value);
122 void touchYChanged(qreal value);
123 void touchSceneXChanged(qreal value);
124 void touchSceneYChanged(qreal value);
125 void immediateRecognitionChanged(bool value);
127protected:
128 void touchEvent(QTouchEvent *event) override;
129 void itemChange(ItemChange change, const ItemChangeData &value) override;
131public: // so tests can access it
132 DirectionalDragAreaPrivate *d;
133};
135#endif // DIRECTIONAL_DRAG_AREA_H