/****************************************************************************+
−
**+
−
** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).+
−
** All rights reserved.+
−
** Contact: Nokia Corporation (qt-info@nokia.com)+
−
**+
−
** This file is part of the examples of the Qt Toolkit.+
−
**+
−
** $QT_BEGIN_LICENSE:LGPL$+
−
** No Commercial Usage+
−
** This file contains pre-release code and may not be distributed.+
−
** You may use this file in accordance with the terms and conditions+
−
** contained in the Technology Preview License Agreement accompanying+
−
** this package.+
−
**+
−
** GNU Lesser General Public License Usage+
−
** Alternatively, this file may be used under the terms of the GNU Lesser+
−
** General Public License version 2.1 as published by the Free Software+
−
** Foundation and appearing in the file LICENSE.LGPL included in the+
−
** packaging of this file.  Please review the following information to+
−
** ensure the GNU Lesser General Public License version 2.1 requirements+
−
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.+
−
**+
−
** In addition, as a special exception, Nokia gives you certain additional+
−
** rights.  These rights are described in the Nokia Qt LGPL Exception+
−
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.+
−
**+
−
** If you have questions regarding the use of this file, please contact+
−
** Nokia at qt-info@nokia.com.+
−
**+
−
**+
−
**+
−
**+
−
**+
−
**+
−
**+
−
**+
−
** $QT_END_LICENSE$+
−
**+
−
****************************************************************************/+
−
+
−
#include "graphicsview.h"+
−
+
−
#include <QScrollBar>+
−
#include <QTouchEvent>+
−
+
−
GraphicsView::GraphicsView(QGraphicsScene *scene, QWidget *parent)+
−
    : QGraphicsView(scene, parent), totalScaleFactor(1)+
−
{+
−
    viewport()->setAttribute(Qt::WA_AcceptTouchEvents);+
−
    setDragMode(ScrollHandDrag);+
−
}+
−
+
−
bool GraphicsView::viewportEvent(QEvent *event)+
−
{+
−
    switch (event->type()) {+
−
    case QEvent::TouchBegin:+
−
    case QEvent::TouchUpdate:+
−
    case QEvent::TouchEnd:+
−
    {+
−
        QTouchEvent *touchEvent = static_cast<QTouchEvent *>(event);+
−
        QList<QTouchEvent::TouchPoint> touchPoints = touchEvent->touchPoints();+
−
        if (touchPoints.count() == 2) {+
−
            // determine scale factor+
−
            const QTouchEvent::TouchPoint &touchPoint0 = touchPoints.first();+
−
            const QTouchEvent::TouchPoint &touchPoint1 = touchPoints.last();+
−
            qreal currentScaleFactor =+
−
                    QLineF(touchPoint0.pos(), touchPoint1.pos()).length()+
−
                    / QLineF(touchPoint0.startPos(), touchPoint1.startPos()).length();+
−
            if (touchEvent->touchPointStates() & Qt::TouchPointReleased) {+
−
                // if one of the fingers is released, remember the current scale+
−
                // factor so that adding another finger later will continue zooming+
−
                // by adding new scale factor to the existing remembered value.+
−
                totalScaleFactor *= currentScaleFactor;+
−
                currentScaleFactor = 1;+
−
            }+
−
            setTransform(QTransform().scale(totalScaleFactor * currentScaleFactor,+
−
                                            totalScaleFactor * currentScaleFactor));+
−
        }+
−
        return true;+
−
    }+
−
    default:+
−
        break;+
−
    }+
−
    return QGraphicsView::viewportEvent(event);+
−
}+
−