mainwindow.cpp Example File
^{opengl/grabber/mainwindow.cpp}

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    **
    ** This file is part of the documentation of the Qt Toolkit.
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    #include <QtGui>
    #include <QtOpenGL>

    #include "glwidget.h"
    #include "mainwindow.h"

    MainWindow::MainWindow()
    {
        centralWidget = new QWidget;
        setCentralWidget(centralWidget);

        glWidget = new GLWidget;
        pixmapLabel = new QLabel;

        glWidgetArea = new QScrollArea;
        glWidgetArea->setWidget(glWidget);
        glWidgetArea->setWidgetResizable(true);
        glWidgetArea->setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
        glWidgetArea->setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
        glWidgetArea->setSizePolicy(QSizePolicy::Ignored, QSizePolicy::Ignored);
        glWidgetArea->setMinimumSize(50, 50);

        pixmapLabelArea = new QScrollArea;
        pixmapLabelArea->setWidget(pixmapLabel);
        pixmapLabelArea->setSizePolicy(QSizePolicy::Ignored, QSizePolicy::Ignored);
        pixmapLabelArea->setMinimumSize(50, 50);

        xSlider = createSlider(SIGNAL(xRotationChanged(int)),
                               SLOT(setXRotation(int)));
        ySlider = createSlider(SIGNAL(yRotationChanged(int)),
                               SLOT(setYRotation(int)));
        zSlider = createSlider(SIGNAL(zRotationChanged(int)),
                               SLOT(setZRotation(int)));

        createActions();
        createMenus();

        QGridLayout *centralLayout = new QGridLayout;
        centralLayout->addWidget(glWidgetArea, 0, 0);
        centralLayout->addWidget(pixmapLabelArea, 0, 1);
        centralLayout->addWidget(xSlider, 1, 0, 1, 2);
        centralLayout->addWidget(ySlider, 2, 0, 1, 2);
        centralLayout->addWidget(zSlider, 3, 0, 1, 2);
        centralWidget->setLayout(centralLayout);

        xSlider->setValue(15 * 16);
        ySlider->setValue(345 * 16);
        zSlider->setValue(0 * 16);

        setWindowTitle(tr("Grabber"));
        resize(400, 300);
    }

    void MainWindow::renderIntoPixmap()
    {
        QSize size = getSize();
        if (size.isValid()) {
            QPixmap pixmap = glWidget->renderPixmap(size.width(), size.height());
            setPixmap(pixmap);
        }
    }

    void MainWindow::grabFrameBuffer()
    {
        QImage image = glWidget->grabFrameBuffer();
        setPixmap(QPixmap::fromImage(image));
    }

    void MainWindow::clearPixmap()
    {
        setPixmap(QPixmap());
    }

    void MainWindow::about()
    {
        QMessageBox::about(this, tr("About Grabber"),
                tr("The <b>Grabber</b> example demonstrates two approaches for "
                   "rendering OpenGL into a Qt pixmap."));
    }

    void MainWindow::createActions()
    {
        renderIntoPixmapAct = new QAction(tr("&Render into Pixmap..."), this);
        renderIntoPixmapAct->setShortcut(tr("Ctrl+R"));
        connect(renderIntoPixmapAct, SIGNAL(triggered()),
                this, SLOT(renderIntoPixmap()));

        grabFrameBufferAct = new QAction(tr("&Grab Frame Buffer"), this);
        grabFrameBufferAct->setShortcut(tr("Ctrl+G"));
        connect(grabFrameBufferAct, SIGNAL(triggered()),
                this, SLOT(grabFrameBuffer()));

        clearPixmapAct = new QAction(tr("&Clear Pixmap"), this);
        clearPixmapAct->setShortcut(tr("Ctrl+L"));
        connect(clearPixmapAct, SIGNAL(triggered()), this, SLOT(clearPixmap()));

        exitAct = new QAction(tr("E&xit"), this);
        exitAct->setShortcut(tr("Ctrl+Q"));
        connect(exitAct, SIGNAL(triggered()), this, SLOT(close()));

        aboutAct = new QAction(tr("&About"), this);
        connect(aboutAct, SIGNAL(triggered()), this, SLOT(about()));

        aboutQtAct = new QAction(tr("About &Qt"), this);
        connect(aboutQtAct, SIGNAL(triggered()), qApp, SLOT(aboutQt()));
    }

    void MainWindow::createMenus()
    {
        fileMenu = menuBar()->addMenu(tr("&File"));
        fileMenu->addAction(renderIntoPixmapAct);
        fileMenu->addAction(grabFrameBufferAct);
        fileMenu->addAction(clearPixmapAct);
        fileMenu->addSeparator();
        fileMenu->addAction(exitAct);

        helpMenu = menuBar()->addMenu(tr("&Help"));
        helpMenu->addAction(aboutAct);
        helpMenu->addAction(aboutQtAct);
    }

    QSlider *MainWindow::createSlider(const char *changedSignal,
                                      const char *setterSlot)
    {
        QSlider *slider = new QSlider(Qt::Horizontal);
        slider->setRange(0, 360 * 16);
        slider->setSingleStep(16);
        slider->setPageStep(15 * 16);
        slider->setTickInterval(15 * 16);
        slider->setTickPosition(QSlider::TicksRight);
        connect(slider, SIGNAL(valueChanged(int)), glWidget, setterSlot);
        connect(glWidget, changedSignal, slider, SLOT(setValue(int)));
        return slider;
    }

    void MainWindow::setPixmap(const QPixmap &pixmap)
    {
        pixmapLabel->setPixmap(pixmap);
        QSize size = pixmap.size();
        if (size - QSize(1, 0) == pixmapLabelArea->maximumViewportSize())
            size -= QSize(1, 0);
        pixmapLabel->resize(size);
    }

    QSize MainWindow::getSize()
    {
        bool ok;
        QString text = QInputDialog::getText(this, tr("Grabber"),
                                             tr("Enter pixmap size:"),
                                             QLineEdit::Normal,
                                             tr("%1 x %2").arg(glWidget->width())
                                                          .arg(glWidget->height()),
                                             &ok);
        if (!ok)
            return QSize();

        QRegExp regExp(tr("([0-9]+) *x *([0-9]+)"));
        if (regExp.exactMatch(text)) {
            int width = regExp.cap(1).toInt();
            int height = regExp.cap(2).toInt();
            if (width > 0 && width < 2048 && height > 0 && height < 2048)
                return QSize(width, height);
        }

        return glWidget->size();
    }