view.cpp Example File

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  #include "view.h"

  #ifndef QT_NO_PRINTER
  #include <QPrinter>
  #include <QPrintDialog>
  #endif
  #ifndef QT_NO_OPENGL
  #include <QtOpenGL>
  #else
  #include <QtWidgets>
  #endif
  #include <qmath.h>

  #ifndef QT_NO_WHEELEVENT
  void GraphicsView::wheelEvent(QWheelEvent *e)
  {
      if (e->modifiers() & Qt::ControlModifier) {
          if (e->delta() > 0)
              view->zoomIn(6);
          else
              view->zoomOut(6);
          e->accept();
      } else {
          QGraphicsView::wheelEvent(e);
      }
  }
  #endif

  View::View(const QString &name, QWidget *parent)
      : QFrame(parent)
  {
      setFrameStyle(Sunken | StyledPanel);
      graphicsView = new GraphicsView(this);
      graphicsView->setRenderHint(QPainter::Antialiasing, false);
      graphicsView->setDragMode(QGraphicsView::RubberBandDrag);
      graphicsView->setOptimizationFlags(QGraphicsView::DontSavePainterState);
      graphicsView->setViewportUpdateMode(QGraphicsView::SmartViewportUpdate);
      graphicsView->setTransformationAnchor(QGraphicsView::AnchorUnderMouse);

      int size = style()->pixelMetric(QStyle::PM_ToolBarIconSize);
      QSize iconSize(size, size);

      QToolButton *zoomInIcon = new QToolButton;
      zoomInIcon->setAutoRepeat(true);
      zoomInIcon->setAutoRepeatInterval(33);
      zoomInIcon->setAutoRepeatDelay(0);
      zoomInIcon->setIcon(QPixmap(":/zoomin.png"));
      zoomInIcon->setIconSize(iconSize);
      QToolButton *zoomOutIcon = new QToolButton;
      zoomOutIcon->setAutoRepeat(true);
      zoomOutIcon->setAutoRepeatInterval(33);
      zoomOutIcon->setAutoRepeatDelay(0);
      zoomOutIcon->setIcon(QPixmap(":/zoomout.png"));
      zoomOutIcon->setIconSize(iconSize);
      zoomSlider = new QSlider;
      zoomSlider->setMinimum(0);
      zoomSlider->setMaximum(500);
      zoomSlider->setValue(250);
      zoomSlider->setTickPosition(QSlider::TicksRight);

      // Zoom slider layout
      QVBoxLayout *zoomSliderLayout = new QVBoxLayout;
      zoomSliderLayout->addWidget(zoomInIcon);
      zoomSliderLayout->addWidget(zoomSlider);
      zoomSliderLayout->addWidget(zoomOutIcon);

      QToolButton *rotateLeftIcon = new QToolButton;
      rotateLeftIcon->setIcon(QPixmap(":/rotateleft.png"));
      rotateLeftIcon->setIconSize(iconSize);
      QToolButton *rotateRightIcon = new QToolButton;
      rotateRightIcon->setIcon(QPixmap(":/rotateright.png"));
      rotateRightIcon->setIconSize(iconSize);
      rotateSlider = new QSlider;
      rotateSlider->setOrientation(Qt::Horizontal);
      rotateSlider->setMinimum(-360);
      rotateSlider->setMaximum(360);
      rotateSlider->setValue(0);
      rotateSlider->setTickPosition(QSlider::TicksBelow);

      // Rotate slider layout
      QHBoxLayout *rotateSliderLayout = new QHBoxLayout;
      rotateSliderLayout->addWidget(rotateLeftIcon);
      rotateSliderLayout->addWidget(rotateSlider);
      rotateSliderLayout->addWidget(rotateRightIcon);

      resetButton = new QToolButton;
      resetButton->setText(tr("0"));
      resetButton->setEnabled(false);

      // Label layout
      QHBoxLayout *labelLayout = new QHBoxLayout;
      label = new QLabel(name);
      label2 = new QLabel(tr("Pointer Mode"));
      selectModeButton = new QToolButton;
      selectModeButton->setText(tr("Select"));
      selectModeButton->setCheckable(true);
      selectModeButton->setChecked(true);
      dragModeButton = new QToolButton;
      dragModeButton->setText(tr("Drag"));
      dragModeButton->setCheckable(true);
      dragModeButton->setChecked(false);
      antialiasButton = new QToolButton;
      antialiasButton->setText(tr("Antialiasing"));
      antialiasButton->setCheckable(true);
      antialiasButton->setChecked(false);
      openGlButton = new QToolButton;
      openGlButton->setText(tr("OpenGL"));
      openGlButton->setCheckable(true);
  #ifndef QT_NO_OPENGL
      openGlButton->setEnabled(QGLFormat::hasOpenGL());
  #else
      openGlButton->setEnabled(false);
  #endif
      printButton = new QToolButton;
      printButton->setIcon(QIcon(QPixmap(":/fileprint.png")));

      QButtonGroup *pointerModeGroup = new QButtonGroup(this);
      pointerModeGroup->setExclusive(true);
      pointerModeGroup->addButton(selectModeButton);
      pointerModeGroup->addButton(dragModeButton);

      labelLayout->addWidget(label);
      labelLayout->addStretch();
      labelLayout->addWidget(label2);
      labelLayout->addWidget(selectModeButton);
      labelLayout->addWidget(dragModeButton);
      labelLayout->addStretch();
      labelLayout->addWidget(antialiasButton);
      labelLayout->addWidget(openGlButton);
      labelLayout->addWidget(printButton);

      QGridLayout *topLayout = new QGridLayout;
      topLayout->addLayout(labelLayout, 0, 0);
      topLayout->addWidget(graphicsView, 1, 0);
      topLayout->addLayout(zoomSliderLayout, 1, 1);
      topLayout->addLayout(rotateSliderLayout, 2, 0);
      topLayout->addWidget(resetButton, 2, 1);
      setLayout(topLayout);

      connect(resetButton, SIGNAL(clicked()), this, SLOT(resetView()));
      connect(zoomSlider, SIGNAL(valueChanged(int)), this, SLOT(setupMatrix()));
      connect(rotateSlider, SIGNAL(valueChanged(int)), this, SLOT(setupMatrix()));
      connect(graphicsView->verticalScrollBar(), SIGNAL(valueChanged(int)),
              this, SLOT(setResetButtonEnabled()));
      connect(graphicsView->horizontalScrollBar(), SIGNAL(valueChanged(int)),
              this, SLOT(setResetButtonEnabled()));
      connect(selectModeButton, SIGNAL(toggled(bool)), this, SLOT(togglePointerMode()));
      connect(dragModeButton, SIGNAL(toggled(bool)), this, SLOT(togglePointerMode()));
      connect(antialiasButton, SIGNAL(toggled(bool)), this, SLOT(toggleAntialiasing()));
      connect(openGlButton, SIGNAL(toggled(bool)), this, SLOT(toggleOpenGL()));
      connect(rotateLeftIcon, SIGNAL(clicked()), this, SLOT(rotateLeft()));
      connect(rotateRightIcon, SIGNAL(clicked()), this, SLOT(rotateRight()));
      connect(zoomInIcon, SIGNAL(clicked()), this, SLOT(zoomIn()));
      connect(zoomOutIcon, SIGNAL(clicked()), this, SLOT(zoomOut()));
      connect(printButton, SIGNAL(clicked()), this, SLOT(print()));

      setupMatrix();
  }

  QGraphicsView *View::view() const
  {
      return static_cast<QGraphicsView *>(graphicsView);
  }

  void View::resetView()
  {
      zoomSlider->setValue(250);
      rotateSlider->setValue(0);
      setupMatrix();
      graphicsView->ensureVisible(QRectF(0, 0, 0, 0));

      resetButton->setEnabled(false);
  }

  void View::setResetButtonEnabled()
  {
      resetButton->setEnabled(true);
  }

  void View::setupMatrix()
  {
      qreal scale = qPow(qreal(2), (zoomSlider->value() - 250) / qreal(50));

      QMatrix matrix;
      matrix.scale(scale, scale);
      matrix.rotate(rotateSlider->value());

      graphicsView->setMatrix(matrix);
      setResetButtonEnabled();
  }

  void View::togglePointerMode()
  {
      graphicsView->setDragMode(selectModeButton->isChecked()
                                ? QGraphicsView::RubberBandDrag
                                : QGraphicsView::ScrollHandDrag);
      graphicsView->setInteractive(selectModeButton->isChecked());
  }

  void View::toggleOpenGL()
  {
  #ifndef QT_NO_OPENGL
      graphicsView->setViewport(openGlButton->isChecked() ? new QGLWidget(QGLFormat(QGL::SampleBuffers)) : new QWidget);
  #endif
  }

  void View::toggleAntialiasing()
  {
      graphicsView->setRenderHint(QPainter::Antialiasing, antialiasButton->isChecked());
  }

  void View::print()
  {
  #if !defined(QT_NO_PRINTER) && !defined(QT_NO_PRINTDIALOG)
      QPrinter printer;
      QPrintDialog dialog(&printer, this);
      if (dialog.exec() == QDialog::Accepted) {
          QPainter painter(&printer);
          graphicsView->render(&painter);
      }
  #endif
  }

  void View::zoomIn(int level)
  {
      zoomSlider->setValue(zoomSlider->value() + level);
  }

  void View::zoomOut(int level)
  {
      zoomSlider->setValue(zoomSlider->value() - level);
  }

  void View::rotateLeft()
  {
      rotateSlider->setValue(rotateSlider->value() - 10);
  }

  void View::rotateRight()
  {
      rotateSlider->setValue(rotateSlider->value() + 10);
  }