diff options
Diffstat (limited to 'examples/qtconcurrent/imagescaling/imagescaling.cpp')
| -rw-r--r-- | examples/qtconcurrent/imagescaling/imagescaling.cpp | 293 |
1 files changed, 188 insertions, 105 deletions
diff --git a/examples/qtconcurrent/imagescaling/imagescaling.cpp b/examples/qtconcurrent/imagescaling/imagescaling.cpp index 6d22bb9598..f380ae9d90 100644 --- a/examples/qtconcurrent/imagescaling/imagescaling.cpp +++ b/examples/qtconcurrent/imagescaling/imagescaling.cpp @@ -1,153 +1,236 @@ -/**************************************************************************** -** -** Copyright (C) 2016 The Qt Company Ltd. -** Contact: https://www.qt.io/licensing/ -** -** This file is part of the examples of the Qt Toolkit. -** -** $QT_BEGIN_LICENSE:BSD$ -** Commercial License Usage -** Licensees holding valid commercial Qt licenses may use this file in -** accordance with the commercial license agreement provided with the -** Software or, alternatively, in accordance with the terms contained in -** a written agreement between you and The Qt Company. For licensing terms -** and conditions see https://www.qt.io/terms-conditions. For further -** information use the contact form at https://www.qt.io/contact-us. -** -** BSD License Usage -** Alternatively, 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 The Qt Company Ltd 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" +// Copyright (C) 2023 The Qt Company Ltd. +// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause -#include <qmath.h> +#include "imagescaling.h" +#include "downloaddialog.h" -#include <functional> +#include <QNetworkReply> -Images::Images(QWidget *parent) - : QWidget(parent) +Images::Images(QWidget *parent) : QWidget(parent), downloadDialog(new DownloadDialog(this)) { - 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); + addUrlsButton = new QPushButton(tr("Add URLs")); +//! [1] + connect(addUrlsButton, &QPushButton::clicked, this, &Images::process); +//! [1] 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); +//! [2] + connect(cancelButton, &QPushButton::clicked, this, &Images::cancel); +//! [2] QHBoxLayout *buttonLayout = new QHBoxLayout(); - buttonLayout->addWidget(openButton); + buttonLayout->addWidget(addUrlsButton); buttonLayout->addWidget(cancelButton); - buttonLayout->addWidget(pauseButton); buttonLayout->addStretch(); + statusBar = new QStatusBar(); + imagesLayout = new QGridLayout(); mainLayout = new QVBoxLayout(); mainLayout->addLayout(buttonLayout); mainLayout->addLayout(imagesLayout); mainLayout->addStretch(); + mainLayout->addWidget(statusBar); setLayout(mainLayout); + +//! [6] + connect(&scalingWatcher, &QFutureWatcher<QList<QImage>>::finished, + this, &Images::scaleFinished); +//! [6] } Images::~Images() { - imageScaling->cancel(); - imageScaling->waitForFinished(); + cancel(); +} + +//! [3] +void Images::process() +{ + // Clean previous state + replies.clear(); + addUrlsButton->setEnabled(false); + + if (downloadDialog->exec() == QDialog::Accepted) { + + const auto urls = downloadDialog->getUrls(); + if (urls.empty()) + return; + + cancelButton->setEnabled(true); + + initLayout(urls.size()); + + downloadFuture = download(urls); + statusBar->showMessage(tr("Downloading...")); +//! [3] + + //! [4] + downloadFuture + .then([this](auto) { + cancelButton->setEnabled(false); + updateStatus(tr("Scaling...")); + //! [16] + scalingWatcher.setFuture(QtConcurrent::run(Images::scaled, + downloadFuture.results())); + //! [16] + }) + //! [4] + //! [5] + .onCanceled([this] { + updateStatus(tr("Download has been canceled.")); + }) + .onFailed([this](QNetworkReply::NetworkError error) { + updateStatus(tr("Download finished with error: %1").arg(error)); + // Abort all pending requests + abortDownload(); + }) + .onFailed([this](const std::exception &ex) { + updateStatus(tr(ex.what())); + }) + //! [5] + .then([this]() { + cancelButton->setEnabled(false); + addUrlsButton->setEnabled(true); + }); + } +} + +//! [7] +void Images::cancel() +{ + statusBar->showMessage(tr("Canceling...")); + + downloadFuture.cancel(); + abortDownload(); +} +//! [7] + +//! [15] +void Images::scaleFinished() +{ + const OptionalImages result = scalingWatcher.result(); + if (result.has_value()) { + const auto scaled = result.value(); + showImages(scaled); + updateStatus(tr("Finished")); + } else { + updateStatus(tr("Failed to extract image data.")); + } + addUrlsButton->setEnabled(true); } +//! [15] -void Images::open() +//! [8] +QFuture<QByteArray> Images::download(const QList<QUrl> &urls) { - // Cancel and wait if we are already loading images. - if (imageScaling->isRunning()) { - imageScaling->cancel(); - imageScaling->waitForFinished(); +//! [8] +//! [9] + QSharedPointer<QPromise<QByteArray>> promise(new QPromise<QByteArray>()); + promise->start(); +//! [9] + + //! [10] + for (const auto &url : urls) { + QSharedPointer<QNetworkReply> reply(qnam.get(QNetworkRequest(url))); + replies.push_back(reply); + //! [10] + + //! [11] + QtFuture::connect(reply.get(), &QNetworkReply::finished).then([=] { + if (promise->isCanceled()) { + if (!promise->future().isFinished()) + promise->finish(); + return; + } + + if (reply->error() != QNetworkReply::NoError) { + if (!promise->future().isFinished()) + throw reply->error(); + } + //! [12] + promise->addResult(reply->readAll()); + + // Report finished on the last download + if (promise->future().resultCount() == urls.size()) + promise->finish(); + //! [12] + }).onFailed([promise] (QNetworkReply::NetworkError error) { + promise->setException(std::make_exception_ptr(error)); + promise->finish(); + }).onFailed([promise] { + const auto ex = std::make_exception_ptr( + std::runtime_error("Unknown error occurred while downloading.")); + promise->setException(ex); + promise->finish(); + }); } + //! [11] + +//! [13] + return promise->future(); +} +//! [13] - // Show a file open dialog at QStandardPaths::PicturesLocation. - QStringList files = QFileDialog::getOpenFileNames(this, tr("Select Images"), - QStandardPaths::writableLocation(QStandardPaths::PicturesLocation), - "*.jpg *.png"); +//! [14] +Images::OptionalImages Images::scaled(const QList<QByteArray> &data) +{ + QList<QImage> scaled; + for (const auto &imgData : data) { + QImage image; + image.loadFromData(imgData); + if (image.isNull()) + return std::nullopt; + + scaled.push_back(image.scaled(100, 100, Qt::KeepAspectRatio)); + } - if (files.isEmpty()) - return; + return scaled; +} +//! [14] - const int imageSize = 100; +void Images::showImages(const QList<QImage> &images) +{ + for (int i = 0; i < images.size(); ++i) { + labels[i]->setAlignment(Qt::AlignCenter); + labels[i]->setPixmap(QPixmap::fromImage(images[i])); + } +} - // Do a simple layout. - qDeleteAll(labels); +void Images::initLayout(qsizetype count) +{ + // Clean old images + QLayoutItem *child; + while ((child = imagesLayout->takeAt(0)) != nullptr) { + child->widget()->setParent(nullptr); + delete child->widget(); + delete child; + } labels.clear(); - int dim = qSqrt(qreal(files.count())) + 1; + // Init the images layout for the new images + const auto dim = int(qSqrt(qreal(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); + imageLabel->setFixedSize(100, 100); + 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) +void Images::updateStatus(const QString &msg) { - labels[num]->setPixmap(QPixmap::fromImage(imageScaling->resultAt(num))); + statusBar->showMessage(msg); } -void Images::finished() +void Images::abortDownload() { - openButton->setEnabled(true); - cancelButton->setEnabled(false); - pauseButton->setEnabled(false); + for (auto reply : replies) + reply->abort(); } |