main.cpp Example File | Qt Quick 5.12.8

- Qt 5.12
- Qt Quick
- Qt Quick Widgets Example
- main.cpp Example File
- Qt 5.12.8 Reference Documentation

# main.cpp Example File

quickwidgets/quickwidget/main.cpp

     /****************************************************************************
     **
     ** Copyright (C) 2017 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 <QQuickWidget>
     #include <QQuickItem>
     #include <QQmlError>
     #include <QtWidgets>
     #include "fbitem.h"

     static bool optMultipleSample = false;
     static bool optCoreProfile = false;

     class MainWindow : public QMainWindow {
         Q_OBJECT
     public:
         MainWindow();

     private slots:
         void quickWidgetStatusChanged(QQuickWidget::Status);
         void sceneGraphError(QQuickWindow::SceneGraphError error, const QString &message);
         void grabFramebuffer();
         void renderToPixmap();
         void grabToImage();
         void createQuickWidgetsInTabs(QMdiArea *mdiArea);

     private:
         QQuickWidget *m_quickWidget;
     };

     MainWindow::MainWindow()
        : m_quickWidget(new QQuickWidget)
     {
         QSurfaceFormat format;
         if (optCoreProfile) {
             format.setVersion(4, 4);
             format.setProfile(QSurfaceFormat::CoreProfile);
         }
         if (optMultipleSample)
             format.setSamples(4);
         m_quickWidget->setFormat(format);

         QMdiArea *centralWidget = new QMdiArea;

         QLCDNumber *lcd = new QLCDNumber;
         lcd->display(1337);
         lcd->setMinimumSize(250,100);
         centralWidget->addSubWindow(lcd);

         QUrl source("qrc:quickwidget/rotatingsquare.qml");

         connect(m_quickWidget, &QQuickWidget::statusChanged,
                 this, &MainWindow::quickWidgetStatusChanged);
         connect(m_quickWidget, &QQuickWidget::sceneGraphError,
                 this, &MainWindow::sceneGraphError);
         m_quickWidget->resize(300,300);
         m_quickWidget->setResizeMode(QQuickWidget::SizeRootObjectToView );
         m_quickWidget->setSource(source);

         centralWidget->addSubWindow(m_quickWidget);

         setCentralWidget(centralWidget);

         QMenu *fileMenu = menuBar()->addMenu(tr("&File"));
         fileMenu->addAction(tr("Grab framebuffer"), this, &MainWindow::grabFramebuffer);
         fileMenu->addAction(tr("Render to pixmap"), this, &MainWindow::renderToPixmap);
         fileMenu->addAction(tr("Grab via grabToImage"), this, &MainWindow::grabToImage);
         fileMenu->addAction(tr("Quit"), qApp, &QCoreApplication::quit);

         QMenu *windowMenu = menuBar()->addMenu(tr("&Window"));
         windowMenu->addAction(tr("Add tab widget"), this,
                               [this, centralWidget] { createQuickWidgetsInTabs(centralWidget); });
     }

     void MainWindow::createQuickWidgetsInTabs(QMdiArea *mdiArea)
     {
         QTabWidget *tabWidget = new QTabWidget;

         const QSize size(400, 400);

         QQuickWidget *w = new QQuickWidget;
         w->resize(size);
         w->setResizeMode(QQuickWidget::SizeRootObjectToView);
         w->setSource(QUrl("qrc:quickwidget/rotatingsquaretab.qml"));

         tabWidget->addTab(w, tr("Plain Quick content"));

         w = new QQuickWidget;
         w->resize(size);
         w->setResizeMode(QQuickWidget::SizeRootObjectToView);
         w->setSource(QUrl("qrc:quickwidget/customgl.qml"));

         tabWidget->addTab(w, tr("Custom OpenGL drawing"));

         mdiArea->addSubWindow(tabWidget);
         tabWidget->show();
     }

     void MainWindow::quickWidgetStatusChanged(QQuickWidget::Status status)
     {
         if (status == QQuickWidget::Error) {
             QStringList errors;
             const auto widgetErrors = m_quickWidget->errors();
             for (const QQmlError &error : widgetErrors)
                 errors.append(error.toString());
             statusBar()->showMessage(errors.join(QStringLiteral(", ")));
         }
     }

     void MainWindow::sceneGraphError(QQuickWindow::SceneGraphError, const QString &message)
     {
          statusBar()->showMessage(message);
     }

     template<class T> void saveToFile(QWidget *parent, T *saveable)
     {
         QFileDialog fd(parent);
         fd.setAcceptMode(QFileDialog::AcceptSave);
         fd.setDefaultSuffix("png");
         fd.selectFile("test.png");
         if (fd.exec() == QDialog::Accepted)
             saveable->save(fd.selectedFiles().first());
     }

     void MainWindow::grabFramebuffer()
     {
         QImage image = m_quickWidget->grabFramebuffer();
         saveToFile(this, &image);
     }

     void MainWindow::renderToPixmap()
     {
         QPixmap pixmap(m_quickWidget->size());
         m_quickWidget->render(&pixmap);
         saveToFile(this, &pixmap);
     }

     void MainWindow::grabToImage()
     {
         QFileDialog fd(this);
         fd.setAcceptMode(QFileDialog::AcceptSave);
         fd.setDefaultSuffix("png");
         fd.selectFile("test_grabToImage.png");
         if (fd.exec() == QDialog::Accepted) {
             QMetaObject::invokeMethod(m_quickWidget->rootObject(), "performLayerBasedGrab",
                                       Q_ARG(QVariant, fd.selectedFiles().first()));
         }
     }

     int main(int argc, char **argv)
     {
         QApplication app(argc, argv);

         QCoreApplication::setApplicationName("Qt QQuickWidget Example");
         QCoreApplication::setOrganizationName("QtProject");
         QCoreApplication::setApplicationVersion(QT_VERSION_STR);
         QCommandLineParser parser;
         parser.setApplicationDescription(QCoreApplication::applicationName());
         parser.addHelpOption();
         parser.addVersionOption();
         QCommandLineOption multipleSampleOption("multisample", "Multisampling");
         parser.addOption(multipleSampleOption);
         QCommandLineOption coreProfileOption("coreprofile", "Use core profile");
         parser.addOption(coreProfileOption);

         parser.process(app);

         optMultipleSample = parser.isSet(multipleSampleOption);
         optCoreProfile = parser.isSet(coreProfileOption);

         qmlRegisterType<FbItem>("QuickWidgetExample", 1, 0, "FbItem");

         MainWindow mainWindow;
         mainWindow.show();

         return app.exec();
     }

     #include "main.moc"