Unity 8
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TouchGate.h
1 /*
2  * Copyright (C) 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  */
16 
17 #ifndef UBUNTU_TOUCH_GATE_H
18 #define UBUNTU_TOUCH_GATE_H
19 
20 #include "UbuntuGesturesQmlGlobal.h"
21 #include "TouchDispatcher.h"
22 
23 #include <QQuickItem>
24 #include <QList>
25 #include <QMap>
26 
27 #define TOUCHGATE_DEBUG 0
28 
29 class TouchOwnershipEvent;
30 
31 /*
32  Blocks the passage of events until ownership over the related touch points is granted.
33 
34  Blocked touch events won't be discarded. Instead they will be buffered until ownership
35  is granted. If ownership is given to another item, the event buffer is cleared.
36 
37  A TouchGate is useful as a mediator for items that do not understand, or gracefully handle,
38  touch canceling. By having a TouchGate in front of them you guarantee that only owned touches (i.e.,
39  touches that won't be canceled later) reaches them.
40  */
41 class UBUNTUGESTURESQML_EXPORT TouchGate : public QQuickItem {
42  Q_OBJECT
43 
44  // Item that's going to receive the touch events that make it through the gate.
45  Q_PROPERTY(QQuickItem* targetItem READ targetItem WRITE setTargetItem NOTIFY targetItemChanged)
46 
47 public:
48  bool event(QEvent *e) override;
49 
50  QQuickItem *targetItem() { return m_dispatcher.targetItem(); }
51  void setTargetItem(QQuickItem *item);
52 
53 Q_SIGNALS:
54  void targetItemChanged(QQuickItem *item);
55 
56 protected:
57  void touchEvent(QTouchEvent *event) override;
58 private:
59  class TouchEvent {
60  public:
61  TouchEvent(const QTouchEvent *event);
62 
63  bool removeTouch(int touchId);
64 
65  QEvent::Type eventType;
66  QTouchDevice *device;
67  Qt::KeyboardModifiers modifiers;
68  QList<QTouchEvent::TouchPoint> touchPoints;
69  QQuickItem *target;
70  QWindow *window;
71  ulong timestamp;
72  };
73 
74  void touchOwnershipEvent(TouchOwnershipEvent *event);
75  bool isTouchPointOwned(int touchId) const;
76  void storeTouchEvent(const QTouchEvent *event);
77  void removeTouchFromStoredEvents(int touchId);
78  void dispatchFullyOwnedEvents();
79  bool eventIsFullyOwned(const TouchEvent &event) const;
80 
81  void dispatchTouchEventToTarget(const TouchEvent &event);
82  void dispatchTouchEventToTarget(QTouchEvent* event);
83 
84  void removeTouchInfoForEndedTouches(const QList<QTouchEvent::TouchPoint> &touchPoints);
85 
86  #if TOUCHGATE_DEBUG
87  QString oldestPendingTouchIdsString();
88  #endif
89 
90  QList<TouchEvent> m_storedEvents;
91 
92  enum {
93  OwnershipUndefined,
94  OwnershipRequested,
95  OwnershipGranted,
96  };
97  class TouchInfo {
98  public:
99  TouchInfo() {ownership = OwnershipUndefined; ended = false;}
100  int ownership;
101  bool ended;
102  };
103  QMap<int, TouchInfo> m_touchInfoMap;
104 
105  TouchDispatcher m_dispatcher;
106 
107  friend class tst_TouchGate;
108 };
109 
110 #endif // UBUNTU_TOUCH_GATE_H