diff options
Diffstat (limited to 'examples/qtconcurrent/imagescaling/imagescaling.cpp')
| -rw-r--r-- | examples/qtconcurrent/imagescaling/imagescaling.cpp | 150 |
1 files changed, 60 insertions, 90 deletions
diff --git a/examples/qtconcurrent/imagescaling/imagescaling.cpp b/examples/qtconcurrent/imagescaling/imagescaling.cpp index 66bb0686c3..f380ae9d90 100644 --- a/examples/qtconcurrent/imagescaling/imagescaling.cpp +++ b/examples/qtconcurrent/imagescaling/imagescaling.cpp @@ -1,64 +1,13 @@ -/**************************************************************************** -** -** Copyright (C) 2020 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." -** -** $QT_END_LICENSE$ -** -****************************************************************************/ +// Copyright (C) 2023 The Qt Company Ltd. +// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause + #include "imagescaling.h" #include "downloaddialog.h" #include <QNetworkReply> -#include <qmath.h> - -#include <functional> - -Images::Images(QWidget *parent) : QWidget(parent), downloadDialog(new DownloadDialog()) +Images::Images(QWidget *parent) : QWidget(parent), downloadDialog(new DownloadDialog(this)) { - setWindowTitle(tr("Image downloading and scaling example")); resize(800, 600); addUrlsButton = new QPushButton(tr("Add URLs")); @@ -87,6 +36,11 @@ Images::Images(QWidget *parent) : QWidget(parent), downloadDialog(new DownloadDi mainLayout->addStretch(); mainLayout->addWidget(statusBar); setLayout(mainLayout); + +//! [6] + connect(&scalingWatcher, &QFutureWatcher<QList<QImage>>::finished, + this, &Images::scaleFinished); +//! [6] } Images::~Images() @@ -99,6 +53,7 @@ void Images::process() { // Clean previous state replies.clear(); + addUrlsButton->setEnabled(false); if (downloadDialog->exec() == QDialog::Accepted) { @@ -114,33 +69,34 @@ void Images::process() statusBar->showMessage(tr("Downloading...")); //! [3] -//! [4] - downloadFuture.then([this](auto) { cancelButton->setEnabled(false); }) - .then(QtFuture::Launch::Async, - [this] { - QMetaObject::invokeMethod(this, - [this] { updateStatus(tr("Scaling...")); }); - return scaled(); - }) -//! [4] -//! [5] - .then(this, [this](const QList<QImage> &scaled) { - showImages(scaled); - updateStatus(tr("Finished")); + //! [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.")); }) -//! [5] -//! [6] - .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) { + .onFailed([this](const std::exception &ex) { updateStatus(tr(ex.what())); + }) + //! [5] + .then([this]() { + cancelButton->setEnabled(false); + addUrlsButton->setEnabled(true); }); -//! [6] } } @@ -154,22 +110,37 @@ void Images::cancel() } //! [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] + //! [8] QFuture<QByteArray> Images::download(const QList<QUrl> &urls) -//! [8] { +//! [8] //! [9] QSharedPointer<QPromise<QByteArray>> promise(new QPromise<QByteArray>()); promise->start(); //! [9] -//! [10] - for (auto url : urls) { + //! [10] + for (const auto &url : urls) { QSharedPointer<QNetworkReply> reply(qnam.get(QNetworkRequest(url))); replies.push_back(reply); -//! [10] + //! [10] -//! [11] + //! [11] QtFuture::connect(reply.get(), &QNetworkReply::finished).then([=] { if (promise->isCanceled()) { if (!promise->future().isFinished()) @@ -181,25 +152,24 @@ QFuture<QByteArray> Images::download(const QList<QUrl> &urls) if (!promise->future().isFinished()) throw reply->error(); } -//! [12] + //! [12] promise->addResult(reply->readAll()); // Report finished on the last download - if (promise->future().resultCount() == urls.size()) { + if (promise->future().resultCount() == urls.size()) promise->finish(); - } -//! [12] - }).onFailed([=] (QNetworkReply::NetworkError error) { + //! [12] + }).onFailed([promise] (QNetworkReply::NetworkError error) { promise->setException(std::make_exception_ptr(error)); promise->finish(); - }).onFailed([=] { + }).onFailed([promise] { const auto ex = std::make_exception_ptr( std::runtime_error("Unknown error occurred while downloading.")); promise->setException(ex); promise->finish(); }); } -//! [11] + //! [11] //! [13] return promise->future(); @@ -207,15 +177,14 @@ QFuture<QByteArray> Images::download(const QList<QUrl> &urls) //! [13] //! [14] -QList<QImage> Images::scaled() const +Images::OptionalImages Images::scaled(const QList<QByteArray> &data) { QList<QImage> scaled; - const auto data = downloadFuture.results(); - for (auto imgData : data) { + for (const auto &imgData : data) { QImage image; image.loadFromData(imgData); if (image.isNull()) - throw std::runtime_error("Failed to load image."); + return std::nullopt; scaled.push_back(image.scaled(100, 100, Qt::KeepAspectRatio)); } @@ -238,6 +207,7 @@ void Images::initLayout(qsizetype count) QLayoutItem *child; while ((child = imagesLayout->takeAt(0)) != nullptr) { child->widget()->setParent(nullptr); + delete child->widget(); delete child; } labels.clear(); |