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| #include "imagescaling.h" |
| |
| #include <qmath.h> |
| |
| #include <functional> |
| |
| Images::Images(QWidget *parent) |
| : QWidget(parent) |
| { |
| setWindowTitle(tr("Image loading and scaling example")); |
| resize(800, 600); |
| |
| imageScaling = new QFutureWatcher<QImage>(this); |
| connect(imageScaling, &QFutureWatcher<QImage>::resultReadyAt, this, &Images::showImage); |
| connect(imageScaling, &QFutureWatcher<QImage>::finished, this, &Images::finished); |
| |
| openButton = new QPushButton(tr("Open Images")); |
| connect(openButton, &QPushButton::clicked, this, &Images::open); |
| |
| cancelButton = new QPushButton(tr("Cancel")); |
| cancelButton->setEnabled(false); |
| connect(cancelButton, &QPushButton::clicked, imageScaling, &QFutureWatcher<QImage>::cancel); |
| |
| pauseButton = new QPushButton(tr("Pause/Resume")); |
| pauseButton->setEnabled(false); |
| connect(pauseButton, &QPushButton::clicked, imageScaling, &QFutureWatcher<QImage>::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 QStandardPaths::PicturesLocation. |
| QStringList files = QFileDialog::getOpenFileNames(this, tr("Select Images"), |
| QStandardPaths::writableLocation(QStandardPaths::PicturesLocation), |
| "*.jpg *.png"); |
| |
| if (files.isEmpty()) |
| return; |
| |
| const int imageSize = 100; |
| |
| // Do a simple layout. |
| qDeleteAll(labels); |
| labels.clear(); |
| |
| int dim = qSqrt(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); |
| } |
| } |
| |
| std::function<QImage(const QString&)> scale = [imageSize](const QString &imageFileName) { |
| QImage image(imageFileName); |
| return image.scaled(QSize(imageSize, imageSize), Qt::IgnoreAspectRatio, Qt::SmoothTransformation); |
| }; |
| |
| // 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); |
| } |