view.cpp Example File

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 #include "view.h"

 #include <QtGui>
 #ifndef QT_NO_OPENGL
 #include <QtOpenGL>
 #endif

 #include <qmath.h>

 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);
     }
 }

 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;
     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()
 {
 #ifndef QT_NO_PRINTER
     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);
 }