widget/qt/mozSwipeGesture.cpp

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
   2 /* vim:expandtab:shiftwidth=4:tabstop=4:
   3  */
   4 /* This Source Code Form is subject to the terms of the Mozilla Public
   5  * License, v. 2.0. If a copy of the MPL was not distributed with this
   6  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   7 #include "mozSwipeGesture.h"
   8 #include <QTouchEvent>
   9 #include <QGraphicsWidget>
  10 #include <nsIDOMSimpleGestureEvent.h>
  11 #include <math.h>
  12
  13 // Percent of screen size
  14 static const float TRIGGER_DISTANCE = 0.3;
  15
  16 // It would be nice to get platform defines for these values
  17 // Maximum finger distance in pixels
  18 const int MAX_FINGER_DISTANCE = 250;
  19 // We could define it as 2*QT_GUI_DOUBLE_CLICK_RADIUS, but it's not available
  20 // due to QTBUG-9630
  21 const int FINGER_DISTANCE_MISTAKE = 50;
  22
  23 QGesture*
  24 MozSwipeGestureRecognizer::create(QObject* target)
  25 {
  26     return new MozSwipeGesture();
  27 }
  28
  29 QGestureRecognizer::Result
  30 MozSwipeGestureRecognizer::recognize(QGesture* aState,
  31                                      QObject* aWatched,
  32                                      QEvent* aEvent)
  33 {
  34     const QTouchEvent* ev = static_cast<const QTouchEvent *>(aEvent);
  35     MozSwipeGesture* swipe = static_cast<MozSwipeGesture *>(aState);
  36
  37     QGestureRecognizer::Result result = QGestureRecognizer::Ignore;
  38
  39     QGraphicsWidget* widget = qobject_cast<QGraphicsWidget*>(aWatched);
  40     if (!widget) {
  41         return result;
  42     }
  43
  44     switch (aEvent->type()) {
  45         case QEvent::TouchBegin:
  46             swipe->mSwipeState = MozSwipeGesture::NOT_STARTED;
  47             result = QGestureRecognizer::MayBeGesture;
  48             break;
  49
  50         case QEvent::TouchEnd:
  51             if (swipe->state() != Qt::NoGesture &&
  52                 swipe->mSwipeState == MozSwipeGesture::TRIGGERED) {
  53                 result = QGestureRecognizer::FinishGesture;
  54             }
  55             else {
  56                 result = QGestureRecognizer::CancelGesture;
  57             }
  58             break;
  59
  60         case QEvent::TouchUpdate:
  61             // We have already handled this swipe
  62             if (swipe->mSwipeState > MozSwipeGesture::STARTED) {
  63                 break;
  64             }
  65
  66             if (ev->touchPoints().count() > 2) {
  67                 swipe->mSwipeState = MozSwipeGesture::CANCELLED;
  68                 result = QGestureRecognizer::CancelGesture;
  69                 break;
  70             }
  71
  72
  73             if (ev->touchPoints().count() == 2) {
  74                swipe->mSwipeState = MozSwipeGesture::STARTED;
  75                QList <QTouchEvent::TouchPoint> touchPoints = ev->touchPoints();
  76                if (!swipe->Update(touchPoints[0], touchPoints[1], widget->size())) {
  77                    result = QGestureRecognizer::CancelGesture;
  78                    swipe->mSwipeState = MozSwipeGesture::CANCELLED;
  79                }
  80                if (swipe->mSwipeState == MozSwipeGesture::TRIGGERED) {
  81                    result = QGestureRecognizer::TriggerGesture;
  82                }
  83                else {
  84                    result = QGestureRecognizer::MayBeGesture;
  85                }
  86            }
  87            break;
  88
  89         default:
  90             result = QGestureRecognizer::Ignore;
  91     }
  92
  93     return result;
  94 }
  95
  96 void
  97 MozSwipeGestureRecognizer::reset(QGesture* aState)
  98 {
  99     MozSwipeGesture* swipe = static_cast<MozSwipeGesture *>(aState);
 100     swipe->mHorizontalDirection = 0;
 101     swipe->mVerticalDirection = 0;
 102     QGestureRecognizer::reset(aState);
 103 }
 104
 105 MozSwipeGesture::MozSwipeGesture()
 106   : mHorizontalDirection(0)
 107   , mVerticalDirection(0)
 108   , mSwipeState(MozSwipeGesture::NOT_STARTED)
 109 {
 110 }
 111
 112 int MozSwipeGesture::Direction()
 113 {
 114     return mHorizontalDirection | mVerticalDirection;
 115 }
 116
 117 bool
 118 MozSwipeGesture::Update(const QTouchEvent::TouchPoint& aFirstPoint,
 119                         const QTouchEvent::TouchPoint& aSecondPoint,
 120                         const QSizeF& aSize)
 121 {
 122     // Check that fingers are not too far away
 123     QPointF fingerDistance = aFirstPoint.pos() - aSecondPoint.pos();
 124     if (fingerDistance.manhattanLength() > MAX_FINGER_DISTANCE) {
 125         return false;
 126     }
 127
 128     // Check that fingers doesn't move too much from the original distance
 129     QPointF startFingerDistance = aFirstPoint.startPos() - aSecondPoint.startPos();
 130     if ((startFingerDistance - fingerDistance).manhattanLength()
 131          > FINGER_DISTANCE_MISTAKE) {
 132         return false;
 133     }
 134
 135     QPointF startPosition = aFirstPoint.startNormalizedPos();
 136     QPointF currentPosition = aFirstPoint.normalizedPos();
 137
 138     float xDistance = fabs(currentPosition.x() - startPosition.x());
 139     float yDistance = fabs(currentPosition.y() - startPosition.y());
 140
 141     startPosition = aFirstPoint.startPos();
 142     currentPosition = aFirstPoint.pos();
 143
 144     if (!aSize.isEmpty()) {
 145         xDistance = fabs(currentPosition.x() - startPosition.x())
 146                     / aSize.width();
 147         yDistance = fabs(currentPosition.y() - startPosition.y())
 148                     / aSize.height();
 149     }
 150
 151     mVerticalDirection = nsIDOMSimpleGestureEvent::DIRECTION_UP;
 152     if (currentPosition.y() > startPosition.y()) {
 153         mVerticalDirection = nsIDOMSimpleGestureEvent::DIRECTION_DOWN;
 154     }
 155
 156     mHorizontalDirection = nsIDOMSimpleGestureEvent::DIRECTION_LEFT;
 157     if (currentPosition.x() > startPosition.x()) {
 158         mHorizontalDirection = nsIDOMSimpleGestureEvent::DIRECTION_RIGHT;
 159     }
 160
 161     if (xDistance > TRIGGER_DISTANCE) {
 162         if (yDistance < TRIGGER_DISTANCE/2) {
 163             mVerticalDirection = 0;
 164         }
 165         mSwipeState = TRIGGERED;
 166     }
 167
 168     if (yDistance > TRIGGER_DISTANCE) {
 169         if (xDistance < TRIGGER_DISTANCE/2) {
 170             mHorizontalDirection = 0;
 171         }
 172         mSwipeState = TRIGGERED;
 173     }
 174
 175     // Use center of touchpoints as hotspot
 176     QPointF hotspot = aFirstPoint.pos() + aSecondPoint.pos();
 177     hotspot /= 2;
 178     setHotSpot(hotspot);
 179     return true;
 180 }