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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,
+** 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
+