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Diffstat (limited to 'examples/qtconcurrent/imagescaling/imagescaling.cpp')
-rw-r--r-- | examples/qtconcurrent/imagescaling/imagescaling.cpp | 146 |
1 files changed, 146 insertions, 0 deletions
diff --git a/examples/qtconcurrent/imagescaling/imagescaling.cpp b/examples/qtconcurrent/imagescaling/imagescaling.cpp new file mode 100644 index 0000000000..6ed7ae7511 --- /dev/null +++ b/examples/qtconcurrent/imagescaling/imagescaling.cpp @@ -0,0 +1,146 @@ +/**************************************************************************** +** +** 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 + |