forked from qt-creator/qt-creator
ImageScaling: Implement the example using TaskTree
Change-Id: Iac54157955d5dffe12a7fdeed904fbcf62a2b667 Reviewed-by: Marcus Tillmanns <marcus.tillmanns@qt.io> Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org> Reviewed-by: <github-actions-qt-creator@cristianadam.eu>
This commit is contained in:
Jarek Kobus
@@ -3,19 +3,24 @@
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#include "imagescaling.h"
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#include "downloaddialog.h"
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#include <tasking/concurrentcall.h>
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#include <tasking/networkquery.h>
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#include <QNetworkReply>
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using namespace Tasking;
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Images::Images(QWidget *parent) : QWidget(parent), downloadDialog(new DownloadDialog(this))
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{
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resize(800, 600);
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addUrlsButton = new QPushButton(tr("Add URLs"));
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QPushButton *addUrlsButton = new QPushButton(tr("Add URLs"));
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connect(addUrlsButton, &QPushButton::clicked, this, &Images::process);
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cancelButton = new QPushButton(tr("Cancel"));
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cancelButton->setEnabled(false);
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connect(cancelButton, &QPushButton::clicked, this, &Images::cancel);
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connect(cancelButton, &QPushButton::clicked, this, [this] {
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statusBar->showMessage(tr("Canceled."));
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taskTree.reset();
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});
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QHBoxLayout *buttonLayout = new QHBoxLayout();
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buttonLayout->addWidget(addUrlsButton);
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@@ -32,141 +37,77 @@ Images::Images(QWidget *parent) : QWidget(parent), downloadDialog(new DownloadDi
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mainLayout->addStretch();
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mainLayout->addWidget(statusBar);
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setLayout(mainLayout);
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connect(&scalingWatcher, &QFutureWatcher<QList<QImage>>::finished,
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this, &Images::scaleFinished);
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}
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Images::~Images()
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static void scale(QPromise<QImage> &promise, const QByteArray &data)
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{
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cancel();
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const auto image = QImage::fromData(data);
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if (image.isNull())
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promise.future().cancel();
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else
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promise.addResult(image.scaled(100, 100, Qt::KeepAspectRatio));
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}
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void Images::process()
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{
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// Clean previous state
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replies.clear();
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addUrlsButton->setEnabled(false);
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if (downloadDialog->exec() == QDialog::Accepted) {
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if (downloadDialog->exec() != QDialog::Accepted)
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return;
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const auto urls = downloadDialog->getUrls();
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if (urls.empty())
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return;
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cancelButton->setEnabled(true);
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initLayout(urls.size());
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downloadFuture = download(urls);
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statusBar->showMessage(tr("Downloading..."));
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downloadFuture
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.then([this](auto) {
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const auto onRootSetup = [this] {
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statusBar->showMessage(tr("Downloading and Scaling..."));
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cancelButton->setEnabled(true);
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};
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const auto onRootDone = [this] {
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statusBar->showMessage(tr("Finished."));
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cancelButton->setEnabled(false);
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updateStatus(tr("Scaling..."));
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scalingWatcher.setFuture(QtConcurrent::run(Images::scaled,
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downloadFuture.results()));
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})
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.onCanceled([this] {
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updateStatus(tr("Download has been canceled."));
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})
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.onFailed([this](QNetworkReply::NetworkError error) {
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updateStatus(tr("Download finished with error: %1").arg(error));
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// Abort all pending requests
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abortDownload();
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})
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.onFailed([this](const std::exception &ex) {
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updateStatus(tr(ex.what()));
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})
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.then([this]() {
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cancelButton->setEnabled(false);
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addUrlsButton->setEnabled(true);
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});
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}
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}
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};
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QList<GroupItem> tasks {
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finishAllAndDone,
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parallel,
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onGroupSetup(onRootSetup),
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onGroupDone(onRootDone)
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};
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void Images::cancel()
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{
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statusBar->showMessage(tr("Canceling..."));
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int i = 0;
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for (const QUrl &url : urls) {
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TreeStorage<QByteArray> storage;
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downloadFuture.cancel();
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abortDownload();
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}
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const auto onDownloadSetup = [this, url](NetworkQuery &query) {
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query.setNetworkAccessManager(&qnam);
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query.setRequest(QNetworkRequest(url));
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};
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const auto onDownloadDone = [storage](const NetworkQuery &query) {
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*storage = query.reply()->readAll();
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};
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const auto onDownloadError = [this, i](const NetworkQuery &query) {
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labels[i]->setText(tr("Download\nError.\nCode: %1.").arg(query.reply()->error()));
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};
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void Images::scaleFinished()
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{
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const OptionalImages result = scalingWatcher.result();
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if (result.has_value()) {
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const auto scaled = result.value();
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showImages(scaled);
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updateStatus(tr("Finished"));
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} else {
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updateStatus(tr("Failed to extract image data."));
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}
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addUrlsButton->setEnabled(true);
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}
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const auto onScalingSetup = [storage](ConcurrentCall<QImage> &data) {
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data.setConcurrentCallData(&scale, *storage);
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};
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const auto onScalingDone = [this, i](const ConcurrentCall<QImage> &data) {
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labels[i]->setPixmap(QPixmap::fromImage(data.result()));
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};
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const auto onScalingError = [this, i](const ConcurrentCall<QImage> &) {
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labels[i]->setText(tr("Image\nData\nError."));
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};
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QFuture<QByteArray> Images::download(const QList<QUrl> &urls)
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{
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QSharedPointer<QPromise<QByteArray>> promise(new QPromise<QByteArray>());
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promise->start();
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for (const auto &url : urls) {
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QSharedPointer<QNetworkReply> reply(qnam.get(QNetworkRequest(url)));
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replies.push_back(reply);
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QtFuture::connect(reply.get(), &QNetworkReply::finished).then([=] {
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if (promise->isCanceled()) {
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if (!promise->future().isFinished())
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promise->finish();
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return;
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const Group group {
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Storage(storage),
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NetworkQueryTask(onDownloadSetup, onDownloadDone, onDownloadError),
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ConcurrentCallTask<QImage>(onScalingSetup, onScalingDone, onScalingError)
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};
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tasks.append(group);
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++i;
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}
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if (reply->error() != QNetworkReply::NoError) {
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if (!promise->future().isFinished())
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throw reply->error();
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}
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promise->addResult(reply->readAll());
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// Report finished on the last download
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if (promise->future().resultCount() == urls.size())
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promise->finish();
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}).onFailed([promise] (QNetworkReply::NetworkError error) {
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promise->setException(std::make_exception_ptr(error));
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promise->finish();
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}).onFailed([promise] {
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const auto ex = std::make_exception_ptr(
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std::runtime_error("Unknown error occurred while downloading."));
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promise->setException(ex);
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promise->finish();
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});
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}
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return promise->future();
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}
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Images::OptionalImages Images::scaled(const QList<QByteArray> &data)
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{
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QList<QImage> scaled;
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for (const auto &imgData : data) {
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QImage image;
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image.loadFromData(imgData);
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if (image.isNull())
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return std::nullopt;
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scaled.push_back(image.scaled(100, 100, Qt::KeepAspectRatio));
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}
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return scaled;
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}
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void Images::showImages(const QList<QImage> &images)
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{
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for (int i = 0; i < images.size(); ++i) {
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labels[i]->setAlignment(Qt::AlignCenter);
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labels[i]->setPixmap(QPixmap::fromImage(images[i]));
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}
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taskTree.reset(new TaskTree(tasks));
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connect(taskTree.get(), &TaskTree::done, this, [this] { taskTree.release()->deleteLater(); });
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taskTree->start();
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}
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void Images::initLayout(qsizetype count)
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@@ -186,19 +127,9 @@ void Images::initLayout(qsizetype count)
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for (int j = 0; j < dim; ++j) {
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QLabel *imageLabel = new QLabel;
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imageLabel->setFixedSize(100, 100);
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imageLabel->setAlignment(Qt::AlignCenter);
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imagesLayout->addWidget(imageLabel, i, j);
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labels.append(imageLabel);
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}
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}
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}
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void Images::updateStatus(const QString &msg)
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{
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statusBar->showMessage(msg);
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}
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void Images::abortDownload()
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{
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for (auto reply : replies)
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reply->abort();
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}
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@@ -4,10 +4,9 @@
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#ifndef IMAGESCALING_H
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#define IMAGESCALING_H
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#include <QtWidgets>
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#include <QtConcurrent>
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#include <QNetworkAccessManager>
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#include <optional>
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#include <QtWidgets>
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#include <tasking/tasktree.h>
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class DownloadDialog;
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class Images : public QWidget
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@@ -15,27 +14,11 @@ class Images : public QWidget
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Q_OBJECT
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public:
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Images(QWidget *parent = nullptr);
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~Images();
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void initLayout(qsizetype count);
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QFuture<QByteArray> download(const QList<QUrl> &urls);
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void updateStatus(const QString &msg);
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void showImages(const QList<QImage> &images);
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void abortDownload();
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public slots:
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void process();
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void cancel();
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private slots:
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void scaleFinished();
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private:
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using OptionalImages = std::optional<QList<QImage>>;
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static OptionalImages scaled(const QList<QByteArray> &data);
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void process();
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void initLayout(qsizetype count);
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QPushButton *addUrlsButton;
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QPushButton *cancelButton;
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QVBoxLayout *mainLayout;
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QList<QLabel *> labels;
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@@ -44,9 +27,7 @@ private:
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DownloadDialog *downloadDialog;
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QNetworkAccessManager qnam;
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QList<QSharedPointer<QNetworkReply>> replies;
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QFuture<QByteArray> downloadFuture;
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QFutureWatcher<OptionalImages> scalingWatcher;
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std::unique_ptr<Tasking::TaskTree> taskTree;
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};
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#endif // IMAGESCALING_H
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