diff -r 41300fa6a67c -r f7bc934e204c util/examples/multitouch/pinchzoom/graphicsview.cpp --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/util/examples/multitouch/pinchzoom/graphicsview.cpp Wed Mar 31 11:06:36 2010 +0300 @@ -0,0 +1,86 @@ +/**************************************************************************** +** +** 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 +#include + +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(event); + QList 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); +}