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+/****************************************************************************
+**
+** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
+** Contact: Qt Software Information (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 either Technology Preview License Agreement or the
+** Beta Release License Agreement.
+**
+** 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 1.0, included in the file LGPL_EXCEPTION.txt in this
+** package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3.0 as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU General Public License version 3.0 requirements will be
+** met: http://www.gnu.org/copyleft/gpl.html.
+**
+** If you are unsure which license is appropriate for your use, please
+** contact the sales department at qt-sales@nokia.com.
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+#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
+