Qt Reference Documentation

# view.cpp Example File

demos/chip/view.cpp

     /****************************************************************************
     **
     ** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies).
     ** All rights reserved.
     ** Contact: Nokia Corporation (qt-info@nokia.com)
     **
     ** This file is part of the demonstration applications of the Qt Toolkit.
     **
     ** $QT_BEGIN_LICENSE:LGPL$
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     ** appearing in the file LICENSE.LGPL included in the packaging of this
     ** file. Please review the following information to ensure the GNU Lesser
     ** General Public License version 2.1 requirements will be met:
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     **
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     ** rights. These rights are described in the Nokia Qt LGPL Exception
     ** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
     **
     ** GNU General Public License Usage
     ** Alternatively, this file may be used under the terms of the GNU General
     ** Public License version 3.0 as published by the Free Software Foundation
     ** and appearing in the file LICENSE.GPL included in the packaging of this
     ** file. Please review the following information to ensure the GNU General
     ** Public License version 3.0 requirements will be met:
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     ** Alternatively, this file may be used in accordance with the terms and
     ** conditions contained in a signed written agreement between you and Nokia.
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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);
     }