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/*
* Copyright (C) 2011 Benjamin Poulain <benjamin@webkit.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
* THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "config.h"
#include "QtPinchGestureRecognizer.h"
#include "QtWebPageEventHandler.h"
#include <QtCore/QLineF>
namespace WebKit {
const qreal pinchInitialTriggerDistanceThreshold = 5.;
static inline int findTouchPointIndex(const QList<QTouchEvent::TouchPoint>& touchPoints, const QtPinchGestureRecognizer::TouchPointInformation& pointInformation)
{
const int touchCount = touchPoints.size();
for (int i = 0; i < touchCount; ++i) {
const QTouchEvent::TouchPoint& touchPoint = touchPoints.at(i);
if (touchPoint.id() == pointInformation.id)
return i;
}
return -1;
}
static inline QPointF computePinchCenter(const QTouchEvent::TouchPoint& point1, const QTouchEvent::TouchPoint& point2)
{
return (point1.pos() + point2.pos()) / 2.0f;
}
QtPinchGestureRecognizer::QtPinchGestureRecognizer(QtWebPageEventHandler* eventHandler)
: QtGestureRecognizer(eventHandler)
{
reset();
}
bool QtPinchGestureRecognizer::recognize(const QTouchEvent* event)
{
if (!interactionEngine())
return false;
const QList<QTouchEvent::TouchPoint>& touchPoints = event->touchPoints();
if (touchPoints.size() < 2) {
if (m_state == GestureRecognized)
interactionEngine()->pinchGestureEnded();
reset();
return false;
}
switch (event->type()) {
case QEvent::TouchBegin:
case QEvent::TouchUpdate:
switch (m_state) {
case NoGesture:
initializeGesture(touchPoints);
return false;
case GestureRecognitionStarted:
case GestureRecognized:
ASSERT(m_point1.isValid());
ASSERT(m_point2.isValid());
const int point1Index = findTouchPointIndex(touchPoints, m_point1);
if (point1Index < 0) {
reset();
return false;
}
const int point2Index = findTouchPointIndex(touchPoints, m_point2);
if (point2Index < 0) {
reset();
return false;
}
const QTouchEvent::TouchPoint& point1 = touchPoints.at(point1Index);
const QTouchEvent::TouchPoint& point2 = touchPoints.at(point2Index);
if (m_state == GestureRecognitionStarted) {
// FIXME: The gesture should only start if the touch events were not accepted at the start of the touch sequence.
const qreal pinchDistance = qAbs(QLineF(point1.screenPos(), point2.screenPos()).length() - QLineF(m_point1.initialScreenPosition, m_point2.initialScreenPosition).length());
if (pinchDistance < pinchInitialTriggerDistanceThreshold)
return false;
m_state = GestureRecognized;
interactionEngine()->pinchGestureStarted(computePinchCenter(point1, point2));
// We reset the initial position to the previous position in order to avoid the jump caused
// by skipping all the events between the beginning and when the threshold is hit.
m_point1.initialPosition = point1.lastPos();
m_point1.initialScreenPosition = point1.lastScreenPos();
m_point2.initialPosition = point2.lastPos();
m_point2.initialScreenPosition = point2.lastScreenPos();
}
ASSERT(m_state == GestureRecognized);
const qreal currentSpanDistance = QLineF(point1.screenPos(), point2.screenPos()).length();
const qreal initialSpanDistance = QLineF(m_point1.initialScreenPosition, m_point2.initialScreenPosition).length();
const qreal totalScaleFactor = currentSpanDistance / initialSpanDistance;
const QPointF touchCenterInPageViewCoordinates = computePinchCenter(point1, point2);
interactionEngine()->pinchGestureRequestUpdate(touchCenterInPageViewCoordinates, totalScaleFactor);
return true;
break;
}
break;
case QEvent::TouchEnd:
if (m_state == GestureRecognized) {
interactionEngine()->pinchGestureEnded();
reset();
return true;
}
reset();
break;
default:
ASSERT_NOT_REACHED();
}
return false;
}
void QtPinchGestureRecognizer::reset()
{
QtGestureRecognizer::reset();
m_point1 = TouchPointInformation();
m_point2 = TouchPointInformation();
}
void QtPinchGestureRecognizer::initializeGesture(const QList<QTouchEvent::TouchPoint>& touchPoints)
{
ASSERT(!m_point1.isValid());
ASSERT(!m_point2.isValid());
m_state = GestureRecognitionStarted;
m_point1 = TouchPointInformation(touchPoints.at(0));
m_point2 = TouchPointInformation(touchPoints.at(1));
ASSERT(m_point1.isValid());
ASSERT(m_point2.isValid());
}
}
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