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/****************************************************************************
**
** 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.
**
** $QT_BEGIN_LICENSE:BSD$
** 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,
** 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."
** $QT_END_LICENSE$
**
****************************************************************************/
#include "imagescaling.h"
#include "math.h"
#ifndef QT_NO_CONCURRENT
const int imageSize = 100;
QImage scale(const QString &imageFileName)
{
QImage image(imageFileName);
return image.scaled(QSize(imageSize, imageSize), Qt::IgnoreAspectRatio, Qt::SmoothTransformation);
}
Images::Images(QWidget *parent)
: QWidget(parent)
{
setWindowTitle(tr("Image loading and scaling example"));
resize(800, 600);
imageScaling = new QFutureWatcher<QImage>(this);
connect(imageScaling, SIGNAL(resultReadyAt(int)), SLOT(showImage(int)));
connect(imageScaling, SIGNAL(finished()), SLOT(finished()));
openButton = new QPushButton(tr("Open Images"));
connect(openButton, SIGNAL(clicked()), SLOT(open()));
cancelButton = new QPushButton(tr("Cancel"));
cancelButton->setEnabled(false);
connect(cancelButton, SIGNAL(clicked()), imageScaling, SLOT(cancel()));
pauseButton = new QPushButton(tr("Pause/Resume"));
pauseButton->setEnabled(false);
connect(pauseButton, SIGNAL(clicked()), imageScaling, SLOT(togglePaused()));
QHBoxLayout *buttonLayout = new QHBoxLayout();
buttonLayout->addWidget(openButton);
buttonLayout->addWidget(cancelButton);
buttonLayout->addWidget(pauseButton);
buttonLayout->addStretch();
imagesLayout = new QGridLayout();
mainLayout = new QVBoxLayout();
mainLayout->addLayout(buttonLayout);
mainLayout->addLayout(imagesLayout);
mainLayout->addStretch();
setLayout(mainLayout);
}
Images::~Images()
{
imageScaling->cancel();
imageScaling->waitForFinished();
}
void Images::open()
{
// Cancel and wait if we are already loading images.
if (imageScaling->isRunning()) {
imageScaling->cancel();
imageScaling->waitForFinished();
}
// Show a file open dialog at QDesktopServices::PicturesLocation.
QStringList files = QFileDialog::getOpenFileNames(this, tr("Select Images"),
QDesktopServices::storageLocation(QDesktopServices::PicturesLocation),
"*.jpg *.png");
if (files.count() == 0)
return;
// Do a simple layout.
qDeleteAll(labels);
labels.clear();
int dim = sqrt(qreal(files.count())) + 1;
for (int i = 0; i < dim; ++i) {
for (int j = 0; j < dim; ++j) {
QLabel *imageLabel = new QLabel;
imageLabel->setFixedSize(imageSize,imageSize);
imagesLayout->addWidget(imageLabel,i,j);
labels.append(imageLabel);
}
}
// Use mapped to run the thread safe scale function on the files.
imageScaling->setFuture(QtConcurrent::mapped(files, scale));
openButton->setEnabled(false);
cancelButton->setEnabled(true);
pauseButton->setEnabled(true);
}
void Images::showImage(int num)
{
labels[num]->setPixmap(QPixmap::fromImage(imageScaling->resultAt(num)));
}
void Images::finished()
{
openButton->setEnabled(true);
cancelButton->setEnabled(false);
pauseButton->setEnabled(false);
}
#endif // QT_NO_CONCURRENT
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