main.cpp Example File

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  ** This file is part of the examples of the Qt Toolkit.
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  #include <QQuickWidget>
  #include <QQuickItem>
  #include <QQmlError>
  #include <QtWidgets>

  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();

  private:
      QQuickWidget *m_quickWidget;
  };

  MainWindow::MainWindow()
     : m_quickWidget(new QQuickWidget)
  {
      QSurfaceFormat format;
      if (QCoreApplication::arguments().contains(QStringLiteral("--coreprofile"))) {
          format.setVersion(4, 4);
          format.setProfile(QSurfaceFormat::CoreProfile);
      }
      if (QCoreApplication::arguments().contains(QStringLiteral("--multisample")))
          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);
  }

  void MainWindow::quickWidgetStatusChanged(QQuickWidget::Status status)
  {
      if (status == QQuickWidget::Error) {
          QStringList errors;
          foreach (const QQmlError &error, m_quickWidget->errors())
              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);

      MainWindow mainWindow;
      mainWindow.show();

      return app.exec();
  }

  #include "main.moc"