mainwindow.cpp Example File

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  #include "mainwindow.h"
  #include "exportdialog.h"

  #include <QtWidgets>
  #include <QSvgRenderer>

  #include "svgview.h"

  static inline QString picturesLocation()
  {
      return QStandardPaths::standardLocations(QStandardPaths::PicturesLocation).value(0, QDir::currentPath());
  }

  MainWindow::MainWindow()
      : QMainWindow()
      , m_view(new SvgView)
      , m_zoomLabel(new QLabel)
  {
      QToolBar *toolBar = new QToolBar(this);
      addToolBar(Qt::TopToolBarArea, toolBar);

      QMenu *fileMenu = menuBar()->addMenu(tr("&File"));
      const QIcon openIcon = QIcon::fromTheme("document-open", QIcon(":/qt-project.org/styles/commonstyle/images/standardbutton-open-32.png"));
      QAction *openAction = fileMenu->addAction(openIcon, tr("&Open..."), this, &MainWindow::openFile);
      openAction->setShortcut(QKeySequence::Open);
      toolBar->addAction(openAction);
      const QIcon exportIcon = QIcon::fromTheme("document-save", QIcon(":/qt-project.org/styles/commonstyle/images/standardbutton-save-32.png"));
      QAction *exportAction = fileMenu->addAction(exportIcon, tr("&Export..."), this, &MainWindow::exportImage);
      exportAction->setToolTip(tr("Export Image"));
      exportAction->setShortcut(Qt::CTRL + Qt::Key_E);
      toolBar->addAction(exportAction);
      QAction *quitAction = fileMenu->addAction(tr("E&xit"), qApp, QCoreApplication::quit);
      quitAction->setShortcuts(QKeySequence::Quit);

      QMenu *viewMenu = menuBar()->addMenu(tr("&View"));
      m_backgroundAction = viewMenu->addAction(tr("&Background"));
      m_backgroundAction->setEnabled(false);
      m_backgroundAction->setCheckable(true);
      m_backgroundAction->setChecked(false);
      connect(m_backgroundAction, &QAction::toggled, m_view, &SvgView::setViewBackground);

      m_outlineAction = viewMenu->addAction(tr("&Outline"));
      m_outlineAction->setEnabled(false);
      m_outlineAction->setCheckable(true);
      m_outlineAction->setChecked(true);
      connect(m_outlineAction, &QAction::toggled, m_view, &SvgView::setViewOutline);

      viewMenu->addSeparator();
      QAction *zoomAction = viewMenu->addAction(tr("Zoom &In"), m_view, &SvgView::zoomIn);
      zoomAction->setShortcut(QKeySequence::ZoomIn);
      zoomAction = viewMenu->addAction(tr("Zoom &Out"), m_view, &SvgView::zoomOut);
      zoomAction->setShortcut(QKeySequence::ZoomOut);
      zoomAction = viewMenu->addAction(tr("Reset Zoom"), m_view, &SvgView::resetZoom);
      zoomAction->setShortcut(Qt::CTRL + Qt::Key_0);

      QMenu *rendererMenu = menuBar()->addMenu(tr("&Renderer"));
      m_nativeAction = rendererMenu->addAction(tr("&Native"));
      m_nativeAction->setCheckable(true);
      m_nativeAction->setChecked(true);
      m_nativeAction->setData(int(SvgView::Native));
  #ifndef QT_NO_OPENGL
      m_glAction = rendererMenu->addAction(tr("&OpenGL"));
      m_glAction->setCheckable(true);
      m_glAction->setData(int(SvgView::OpenGL));
  #endif
      m_imageAction = rendererMenu->addAction(tr("&Image"));
      m_imageAction->setCheckable(true);
      m_imageAction->setData(int(SvgView::Image));

      rendererMenu->addSeparator();
      m_highQualityAntialiasingAction = rendererMenu->addAction(tr("&High Quality Antialiasing"));
      m_highQualityAntialiasingAction->setEnabled(false);
      m_highQualityAntialiasingAction->setCheckable(true);
      m_highQualityAntialiasingAction->setChecked(false);
      connect(m_highQualityAntialiasingAction, &QAction::toggled, m_view, &SvgView::setHighQualityAntialiasing);
  #ifdef QT_NO_OPENGL
      m_highQualityAntialiasingAction->setVisible(false);
  #endif

      QActionGroup *rendererGroup = new QActionGroup(this);
      rendererGroup->addAction(m_nativeAction);
  #ifndef QT_NO_OPENGL
      rendererGroup->addAction(m_glAction);
  #endif
      rendererGroup->addAction(m_imageAction);

      menuBar()->addMenu(rendererMenu);

      connect(rendererGroup, &QActionGroup::triggered,
              [this] (QAction *a) { setRenderer(a->data().toInt()); });

      QMenu *help = menuBar()->addMenu(tr("&Help"));
      help->addAction(tr("About Qt"), qApp, &QApplication::aboutQt);

      setCentralWidget(m_view);

      m_zoomLabel->setToolTip(tr("Use the mouse wheel to zoom"));
      statusBar()->addPermanentWidget(m_zoomLabel);
      updateZoomLabel();
      connect(m_view, &SvgView::zoomChanged, this, &MainWindow::updateZoomLabel);
  }

  void MainWindow::openFile()
  {
      QFileDialog fileDialog(this);
      fileDialog.setAcceptMode(QFileDialog::AcceptOpen);
      fileDialog.setMimeTypeFilters(QStringList() << "image/svg+xml" << "image/svg+xml-compressed");
      fileDialog.setWindowTitle(tr("Open SVG File"));
      if (m_currentPath.isEmpty())
          fileDialog.setDirectory(picturesLocation());

      while (fileDialog.exec() == QDialog::Accepted && !loadFile(fileDialog.selectedFiles().constFirst()))
          ;
  }

  bool MainWindow::loadFile(const QString &fileName)
  {
      if (!QFileInfo::exists(fileName) || !m_view->openFile(fileName)) {
          QMessageBox::critical(this, tr("Open SVG File"),
                                tr("Could not open file '%1'.").arg(QDir::toNativeSeparators(fileName)));
          return false;
      }

      if (!fileName.startsWith(":/")) {
          m_currentPath = fileName;
          setWindowFilePath(fileName);
          const QSize size = m_view->svgSize();
          const QString message =
              tr("Opened %1, %2x%3").arg(QFileInfo(fileName).fileName()).arg(size.width()).arg(size.width());
          statusBar()->showMessage(message);
      }

      m_outlineAction->setEnabled(true);
      m_backgroundAction->setEnabled(true);

      const QSize availableSize = QApplication::desktop()->availableGeometry(this).size();
      resize(m_view->sizeHint().expandedTo(availableSize / 4) + QSize(80, 80 + menuBar()->height()));

      return true;
  }

  void MainWindow::setRenderer(int renderMode)
  {

      m_highQualityAntialiasingAction->setEnabled(renderMode == SvgView::OpenGL);
      m_view->setRenderer(static_cast<SvgView::RendererType>(renderMode));
  }

  void MainWindow::exportImage()
  {
      ExportDialog exportDialog(this);
      exportDialog.setExportSize(m_view->svgSize());
      QString fileName;
      if (m_currentPath.isEmpty()) {
          fileName = picturesLocation() + QLatin1String("/export.png");
      } else {
          const QFileInfo fi(m_currentPath);
          fileName = fi.absolutePath() + QLatin1Char('/') + fi.baseName() + QLatin1String(".png");
      }
      exportDialog.setExportFileName(fileName);

      while (true) {
          if (exportDialog.exec() != QDialog::Accepted)
              break;

          const QSize imageSize = exportDialog.exportSize();
          QImage image(imageSize, QImage::Format_ARGB32);
          image.fill(Qt::transparent);
          QPainter painter;
          painter.begin(&image);
          m_view->renderer()->render(&painter, QRectF(QPointF(), QSizeF(imageSize)));
          painter.end();

          const QString fileName = exportDialog.exportFileName();
          if (image.save(fileName)) {

              const QString message = tr("Exported %1, %2x%3, %4 bytes")
                  .arg(QDir::toNativeSeparators(fileName)).arg(imageSize.width()).arg(imageSize.height())
                  .arg(QFileInfo(fileName).size());
              statusBar()->showMessage(message);
              break;
          } else {
              QMessageBox::critical(this, tr("Export Image"),
                                    tr("Could not write file '%1'.").arg(QDir::toNativeSeparators(fileName)));
          }
      }
  }

  void MainWindow::updateZoomLabel()
  {
      const int percent = qRound(m_view->zoomFactor() * qreal(100));
      m_zoomLabel->setText(QString::number(percent) + QLatin1Char('%'));
  }