code.vuplus.com Git - vuplus_webkit/blob - Source/WebKit2/UIProcess/qt/QtPinchGestureRecognizer.cpp

   1 /*
   2  * Copyright (C) 2011 Benjamin Poulain <benjamin@webkit.org>
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  * 1. Redistributions of source code must retain the above copyright
   8  *    notice, this list of conditions and the following disclaimer.
   9  * 2. Redistributions in binary form must reproduce the above copyright
  10  *    notice, this list of conditions and the following disclaimer in the
  11  *    documentation and/or other materials provided with the distribution.
  12  *
  13  * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
  14  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
  15  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  16  * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
  17  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  18  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  19  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  20  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  21  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  22  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
  23  * THE POSSIBILITY OF SUCH DAMAGE.
  24  */
  25
  26 #include "config.h"
  27 #include "QtPinchGestureRecognizer.h"
  28
  29 #include "ViewportInteractionEngine.h"
  30 #include <QtCore/QLineF>
  31
  32 namespace WebKit {
  33
  34 const qreal pinchInitialTriggerDistanceThreshold = 5.;
  35
  36 static inline int findTouchPointIndex(const QList<QTouchEvent::TouchPoint>& touchPoints, const QtPinchGestureRecognizer::TouchPointInformation& pointInformation)
  37 {
  38     const int touchCount = touchPoints.size();
  39     for (int i = 0; i < touchCount; ++i) {
  40         const QTouchEvent::TouchPoint& touchPoint = touchPoints.at(i);
  41         if (touchPoint.id() == pointInformation.id)
  42             return i;
  43     }
  44     return -1;
  45 }
  46
  47 static inline QPointF computeTouchCenter(const QTouchEvent::TouchPoint& point1, const QTouchEvent::TouchPoint& point2)
  48 {
  49     return (point1.pos() + point2.pos()) / 2.0f;
  50 }
  51
  52 QtPinchGestureRecognizer::QtPinchGestureRecognizer(ViewportInteractionEngine* interactionEngine)
  53     : QtGestureRecognizer(interactionEngine)
  54 {
  55     reset();
  56 }
  57
  58 bool QtPinchGestureRecognizer::recognize(const QTouchEvent* event)
  59 {
  60     const QList<QTouchEvent::TouchPoint>& touchPoints = event->touchPoints();
  61     if (touchPoints.size() < 2) {
  62         if (m_state == GestureRecognized)
  63             m_viewportInteractionEngine->pinchGestureEnded();
  64         reset();
  65         return false;
  66     }
  67
  68     switch (event->type()) {
  69     case QEvent::TouchBegin:
  70     case QEvent::TouchUpdate:
  71         switch (m_state) {
  72         case NoGesture:
  73             initializeGesture(touchPoints);
  74             return false;
  75         case GestureRecognitionStarted:
  76         case GestureRecognized:
  77             ASSERT(m_point1.isValid());
  78             ASSERT(m_point2.isValid());
  79
  80             const int point1Index = findTouchPointIndex(touchPoints, m_point1);
  81             if (point1Index < 0) {
  82                 reset();
  83                 return false;
  84             }
  85             const int point2Index = findTouchPointIndex(touchPoints, m_point2);
  86             if (point2Index < 0) {
  87                 reset();
  88                 return false;
  89             }
  90
  91             const QTouchEvent::TouchPoint& point1 = touchPoints.at(point1Index);
  92             const QTouchEvent::TouchPoint& point2 = touchPoints.at(point2Index);
  93             if (m_state == GestureRecognitionStarted) {
  94                 // FIXME: The gesture should only start if the touch events were not accepted at the start of the touch sequence.
  95                 const qreal pinchDistance = qAbs(QLineF(point1.screenPos(), point2.screenPos()).length() - QLineF(m_point1.initialScreenPosition, m_point2.initialScreenPosition).length());
  96                 if (pinchDistance < pinchInitialTriggerDistanceThreshold)
  97                     return false;
  98                 m_state = GestureRecognized;
  99                 m_viewportInteractionEngine->pinchGestureStarted();
 100
 101                 // We reset the initial position to the previous position in order to avoid the jump caused
 102                 // by skipping all the events between the beginning and when the threshold is hit.
 103                 m_point1.initialPosition = point1.lastPos();
 104                 m_point1.initialScreenPosition = point1.lastScreenPos();
 105                 m_point2.initialPosition = point2.lastPos();
 106                 m_point2.initialScreenPosition = point2.lastScreenPos();
 107             }
 108             ASSERT(m_state == GestureRecognized);
 109             const qreal currentSpanDistance = QLineF(point1.screenPos(), point2.screenPos()).length();
 110             const qreal initialSpanDistance = QLineF(m_point1.initialScreenPosition, m_point2.initialScreenPosition).length();
 111             const qreal totalScaleFactor = currentSpanDistance / initialSpanDistance;
 112             const QPointF touchCenterInPageViewCoordinate = computeTouchCenter(point1, point2);
 113             m_viewportInteractionEngine->pinchGestureRequestUpdate(touchCenterInPageViewCoordinate, totalScaleFactor);
 114             return true;
 115             break;
 116         }
 117         break;
 118     case QEvent::TouchEnd:
 119         if (m_state == GestureRecognized) {
 120             m_viewportInteractionEngine->pinchGestureEnded();
 121             reset();
 122             return true;
 123         }
 124         reset();
 125         break;
 126     default:
 127         ASSERT_NOT_REACHED();
 128     }
 129
 130     return false;
 131 }
 132
 133 void QtPinchGestureRecognizer::reset()
 134 {
 135     QtGestureRecognizer::reset();
 136     m_point1 = TouchPointInformation();
 137     m_point2 = TouchPointInformation();
 138 }
 139
 140 void QtPinchGestureRecognizer::initializeGesture(const QList<QTouchEvent::TouchPoint>& touchPoints)
 141 {
 142     ASSERT(!m_point1.isValid());
 143     ASSERT(!m_point2.isValid());
 144
 145     m_state = GestureRecognitionStarted;
 146
 147     m_point1 = TouchPointInformation(touchPoints.at(0));
 148     m_point2 = TouchPointInformation(touchPoints.at(1));
 149
 150     ASSERT(m_point1.isValid());
 151     ASSERT(m_point2.isValid());
 152 }
 153
 154 }