qt5base-lts/examples/gestures/imagegestures/imagewidget.cpp

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/****************************************************************************
**
** Copyright (C) 2011 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.
**
** $QT_BEGIN_LICENSE:BSD$
** You may use this file under the terms of the BSD license as follows:
**
** "Redistribution and use in source and binary forms, with or without
** modification, are permitted provided that the following conditions are
** met:
** * Redistributions of source code must retain the above copyright
** notice, this list of conditions and the following disclaimer.
** * 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.
** * Neither the name of Nokia Corporation and its Subsidiary(-ies) nor
** the names of its contributors may be used to endorse or promote
** products derived from this software without specific prior written
** permission.
**
** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND 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 THE COPYRIGHT
** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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** 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."
** $QT_END_LICENSE$
**
****************************************************************************/
#include "imagewidget.h"
#include <QtGui>
//! [constructor]
ImageWidget::ImageWidget(QWidget *parent)
: QWidget(parent),
position(0),
horizontalOffset(0),
verticalOffset(0),
rotationAngle(0),
scaleFactor(1),
currentStepScaleFactor(1)
{
setMinimumSize(QSize(100,100));
//! [enable gestures]
grabGesture(Qt::PanGesture);
grabGesture(Qt::PinchGesture);
grabGesture(Qt::SwipeGesture);
//! [enable gestures]
}
//! [constructor]
//! [event handler]
bool ImageWidget::event(QEvent *event)
{
if (event->type() == QEvent::Gesture)
return gestureEvent(static_cast<QGestureEvent*>(event));
return QWidget::event(event);
}
//! [event handler]
void ImageWidget::paintEvent(QPaintEvent*)
{
QPainter p(this);
float iw = currentImage.width();
float ih = currentImage.height();
float wh = height();
float ww = width();
p.translate(ww/2, wh/2);
p.translate(horizontalOffset, verticalOffset);
p.rotate(rotationAngle);
p.scale(currentStepScaleFactor * scaleFactor, currentStepScaleFactor * scaleFactor);
p.translate(-iw/2, -ih/2);
p.drawImage(0, 0, currentImage);
}
void ImageWidget::mouseDoubleClickEvent(QMouseEvent *)
{
rotationAngle = 0;
scaleFactor = 1;
currentStepScaleFactor = 1;
verticalOffset = 0;
horizontalOffset = 0;
update();
}
//! [gesture event handler]
bool ImageWidget::gestureEvent(QGestureEvent *event)
{
if (QGesture *swipe = event->gesture(Qt::SwipeGesture))
swipeTriggered(static_cast<QSwipeGesture *>(swipe));
else if (QGesture *pan = event->gesture(Qt::PanGesture))
panTriggered(static_cast<QPanGesture *>(pan));
if (QGesture *pinch = event->gesture(Qt::PinchGesture))
pinchTriggered(static_cast<QPinchGesture *>(pinch));
return true;
}
//! [gesture event handler]
void ImageWidget::panTriggered(QPanGesture *gesture)
{
#ifndef QT_NO_CURSOR
switch (gesture->state()) {
case Qt::GestureStarted:
case Qt::GestureUpdated:
setCursor(Qt::SizeAllCursor);
break;
default:
setCursor(Qt::ArrowCursor);
}
#endif
QPointF delta = gesture->delta();
horizontalOffset += delta.x();
verticalOffset += delta.y();
update();
}
void ImageWidget::pinchTriggered(QPinchGesture *gesture)
{
QPinchGesture::ChangeFlags changeFlags = gesture->changeFlags();
if (changeFlags & QPinchGesture::RotationAngleChanged) {
qreal value = gesture->property("rotationAngle").toReal();
qreal lastValue = gesture->property("lastRotationAngle").toReal();
rotationAngle += value - lastValue;
}
if (changeFlags & QPinchGesture::ScaleFactorChanged) {
qreal value = gesture->property("scaleFactor").toReal();
currentStepScaleFactor = value;
}
if (gesture->state() == Qt::GestureFinished) {
scaleFactor *= currentStepScaleFactor;
currentStepScaleFactor = 1;
}
update();
}
//! [swipe function]
void ImageWidget::swipeTriggered(QSwipeGesture *gesture)
{
if (gesture->state() == Qt::GestureFinished) {
if (gesture->horizontalDirection() == QSwipeGesture::Left
|| gesture->verticalDirection() == QSwipeGesture::Up)
goPrevImage();
else
goNextImage();
update();
}
}
//! [swipe function]
void ImageWidget::resizeEvent(QResizeEvent*)
{
update();
}
void ImageWidget::openDirectory(const QString &path)
{
this->path = path;
QDir dir(path);
QStringList nameFilters;
nameFilters << "*.jpg" << "*.png";
files = dir.entryList(nameFilters, QDir::Files|QDir::Readable, QDir::Name);
position = 0;
goToImage(0);
update();
}
QImage ImageWidget::loadImage(const QString &fileName)
{
QImageReader reader(fileName);
if (!reader.canRead()) {
qDebug() << fileName << ": can't load image";
return QImage();
}
QImage image;
if (!reader.read(&image)) {
qDebug() << fileName << ": corrupted image";
return QImage();
}
return image;
}
void ImageWidget::goNextImage()
{
if (files.isEmpty())
return;
if (position < files.size()-1) {
++position;
prevImage = currentImage;
currentImage = nextImage;
if (position+1 < files.size())
nextImage = loadImage(path+QLatin1String("/")+files.at(position+1));
else
nextImage = QImage();
}
update();
}
void ImageWidget::goPrevImage()
{
if (files.isEmpty())
return;
if (position > 0) {
--position;
nextImage = currentImage;
currentImage = prevImage;
if (position > 0)
prevImage = loadImage(path+QLatin1String("/")+files.at(position-1));
else
prevImage = QImage();
}
update();
}
void ImageWidget::goToImage(int index)
{
if (files.isEmpty())
return;
if (index < 0 || index >= files.size()) {
qDebug() << "goToImage: invalid index: " << index;
return;
}
if (index == position+1) {
goNextImage();
return;
}
if (position > 0 && index == position-1) {
goPrevImage();
return;
}
position = index;
if (index > 0)
prevImage = loadImage(path+QLatin1String("/")+files.at(position-1));
else
prevImage = QImage();
currentImage = loadImage(path+QLatin1String("/")+files.at(position));
if (position+1 < files.size())
nextImage = loadImage(path+QLatin1String("/")+files.at(position+1));
else
nextImage = QImage();
update();
}