Qt 4.0: mainwindow.cpp Example File (opengl/grabber/mainwindow.cpp)

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# mainwindow.cpp Example File
opengl/grabber/mainwindow.cpp

        /****************************************************************************
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        **
        ** This file is part of the documentation of the Qt Toolkit.
        **
        ** This file may be used under the terms of the GNU General Public
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    ** and appearing in the file LICENSE.GPL included in the packaging of
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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(0).toInt();
                int height = regExp.cap(1).toInt();
                if (width > 0 && width < 2048 && height > 0 && height < 2048)
                    return QSize(width, height);
            }

            return glWidget->size();
        }