Unity 8
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  TouchGate(QQuickItem *parent = nullptr);
49 
50  bool event(QEvent *e) override;
51 
52  QQuickItem *targetItem() { return m_dispatcher.targetItem(); }
53  void setTargetItem(QQuickItem *item);
54 
55 Q_SIGNALS:
56  void targetItemChanged(QQuickItem *item);
57 
58 protected:
59  void touchEvent(QTouchEvent *event) override;
60  void itemChange(ItemChange change, const ItemChangeData &value) override;
61 
62 private Q_SLOTS:
63  void onEnabledChanged();
64 
65 private:
66  void reset();
67 
68  class TouchEvent {
69  public:
70  TouchEvent(QTouchDevice *device,
71  Qt::KeyboardModifiers modifiers,
72  const QList<QTouchEvent::TouchPoint> &touchPoints,
73  QWindow *window,
74  ulong timestamp);
75 
76  bool removeTouch(int touchId);
77 
78  QTouchDevice *device;
79  Qt::KeyboardModifiers modifiers;
80  QList<QTouchEvent::TouchPoint> touchPoints;
81  QWindow *window;
82  ulong timestamp;
83  };
84 
85  void touchOwnershipEvent(TouchOwnershipEvent *event);
86  bool isTouchPointOwned(int touchId) const;
87  void storeTouchEvent(QTouchDevice *device,
88  Qt::KeyboardModifiers modifiers,
89  const QList<QTouchEvent::TouchPoint> &touchPoints,
90  QWindow *window,
91  ulong timestamp);
92  void removeTouchFromStoredEvents(int touchId);
93  void dispatchFullyOwnedEvents();
94  bool eventIsFullyOwned(const TouchEvent &event) const;
95 
96  void dispatchTouchEventToTarget(const TouchEvent &event);
97 
98  void removeTouchInfoForEndedTouches(const QList<QTouchEvent::TouchPoint> &touchPoints);
99 
100  #if TOUCHGATE_DEBUG
101  QString oldestPendingTouchIdsString();
102  #endif
103 
104  QList<TouchEvent> m_storedEvents;
105 
106  enum {
107  OwnershipUndefined,
108  OwnershipRequested,
109  OwnershipGranted,
110  };
111  class TouchInfo {
112  public:
113  TouchInfo() {ownership = OwnershipUndefined; ended = false;}
114  int ownership;
115  bool ended;
116  };
117  QMap<int, TouchInfo> m_touchInfoMap;
118 
119  TouchDispatcher m_dispatcher;
120 
121  friend class tst_TouchGate;
122 };
123 
124 #endif // UBUNTU_TOUCH_GATE_H