Вывод изображения на форму

#include <QApplication>
 
#include "imageviewer.h"
 
int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
    ImageViewer imageViewer;
#if defined(Q_OS_SYMBIAN)
    imageViewer.showMaximized();
#else
    imageViewer.show();
#endif
    return app.exec();
}

#ifndef IMAGEVIEWER_H
#define IMAGEVIEWER_H
 
#include <QMainWindow>
#include <QPrinter>
 
QT_BEGIN_NAMESPACE
class QAction;
class QLabel;
class QMenu;
class QScrollArea;
class QScrollBar;
QT_END_NAMESPACE
 
//! [0]
class ImageViewer : public QMainWindow
{
    Q_OBJECT
 
public:
    ImageViewer();
 
private slots:
    void open();
    void print();
    void zoomIn();
    void zoomOut();
    void normalSize();
    void fitToWindow();
    void about();
 
private:
    void createActions();
    void createMenus();
    void updateActions();
    void scaleImage(double factor);
    void adjustScrollBar(QScrollBar *scrollBar, double factor);
 
    QLabel *imageLabel;
    QScrollArea *scrollArea;
    double scaleFactor;
 
#ifndef QT_NO_PRINTER
    QPrinter printer;
#endif
 
    QAction *openAct;
    QAction *printAct;
    QAction *exitAct;
    QAction *zoomInAct;
    QAction *zoomOutAct;
    QAction *normalSizeAct;
    QAction *fitToWindowAct;
    QAction *aboutAct;
    QAction *aboutQtAct;
 
    QMenu *fileMenu;
    QMenu *viewMenu;
    QMenu *helpMenu;
};
//! [0]
 
#endif

#include <QtGui>
 
#include "imageviewer.h"
 
//! [0]
ImageViewer::ImageViewer()
{
    imageLabel = new QLabel;
    imageLabel->setBackgroundRole(QPalette::Base);
    imageLabel->setSizePolicy(QSizePolicy::Ignored, QSizePolicy::Ignored);
    imageLabel->setScaledContents(true);
 
    scrollArea = new QScrollArea;
    scrollArea->setBackgroundRole(QPalette::Dark);
    scrollArea->setWidget(imageLabel);
    setCentralWidget(scrollArea);
 
    createActions();
    createMenus();
 
    setWindowTitle(tr("Image Viewer"));
    resize(500, 400);
}
//! [0]
 
//! [1]
void ImageViewer::open()
//! [1] //! [2]
{
    QString fileName = QFileDialog::getOpenFileName(this,
                                    tr("Open File"), QDir::currentPath());
    if (!fileName.isEmpty()) {
        QImage image(fileName);
        if (image.isNull()) {
            QMessageBox::information(this, tr("Image Viewer"),
                                     tr("Cannot load %1.").arg(fileName));
            return;
        }
//! [2] //! [3]
        imageLabel->setPixmap(QPixmap::fromImage(image));
//! [3] //! [4]
        scaleFactor = 1.0;
 
        printAct->setEnabled(true);
        fitToWindowAct->setEnabled(true);
        updateActions();
 
        if (!fitToWindowAct->isChecked())
            imageLabel->adjustSize();
    }
}
//! [4]
 
//! [5]
void ImageViewer::print()
//! [5] //! [6]
{
    Q_ASSERT(imageLabel->pixmap());
#ifndef QT_NO_PRINTER
//! [6] //! [7]
    QPrintDialog dialog(&printer, this);
//! [7] //! [8]
    if (dialog.exec()) {
        QPainter painter(&printer);
        QRect rect = painter.viewport();
        QSize size = imageLabel->pixmap()->size();
        size.scale(rect.size(), Qt::KeepAspectRatio);
        painter.setViewport(rect.x(), rect.y(), size.width(), size.height());
        painter.setWindow(imageLabel->pixmap()->rect());
        painter.drawPixmap(0, 0, *imageLabel->pixmap());
    }
#endif
}
//! [8]
 
//! [9]
void ImageViewer::zoomIn()
//! [9] //! [10]
{
    scaleImage(1.25);
}
 
void ImageViewer::zoomOut()
{
    scaleImage(0.8);
}
 
//! [10] //! [11]
void ImageViewer::normalSize()
//! [11] //! [12]
{
    imageLabel->adjustSize();
    scaleFactor = 1.0;
}
//! [12]
 
//! [13]
void ImageViewer::fitToWindow()
//! [13] //! [14]
{
    bool fitToWindow = fitToWindowAct->isChecked();
    scrollArea->setWidgetResizable(fitToWindow);
    if (!fitToWindow) {
        normalSize();
    }
    updateActions();
}
//! [14]
 
 
//! [15]
void ImageViewer::about()
//! [15] //! [16]
{
    QMessageBox::about(this, tr("About Image Viewer"),
            tr("<p>The <b>Image Viewer</b> example shows how to combine QLabel "
               "and QScrollArea to display an image. QLabel is typically used "
               "for displaying a text, but it can also display an image. "
               "QScrollArea provides a scrolling view around another widget. "
               "If the child widget exceeds the size of the frame, QScrollArea "
               "automatically provides scroll bars. </p><p>The example "
               "demonstrates how QLabel's ability to scale its contents "
               "(QLabel::scaledContents), and QScrollArea's ability to "
               "automatically resize its contents "
               "(QScrollArea::widgetResizable), can be used to implement "
               "zooming and scaling features. </p><p>In addition the example "
               "shows how to use QPainter to print an image.</p>"));
}
//! [16]
 
//! [17]
void ImageViewer::createActions()
//! [17] //! [18]
{
    openAct = new QAction(tr("&Open..."), this);
    openAct->setShortcut(tr("Ctrl+O"));
    connect(openAct, SIGNAL(triggered()), this, SLOT(open()));
 
    printAct = new QAction(tr("&Print..."), this);
    printAct->setShortcut(tr("Ctrl+P"));
    printAct->setEnabled(false);
    connect(printAct, SIGNAL(triggered()), this, SLOT(print()));
 
    exitAct = new QAction(tr("E&xit"), this);
    exitAct->setShortcut(tr("Ctrl+Q"));
    connect(exitAct, SIGNAL(triggered()), this, SLOT(close()));
 
    zoomInAct = new QAction(tr("Zoom &In (25%)"), this);
    zoomInAct->setShortcut(tr("Ctrl++"));
    zoomInAct->setEnabled(false);
    connect(zoomInAct, SIGNAL(triggered()), this, SLOT(zoomIn()));
 
    zoomOutAct = new QAction(tr("Zoom &Out (25%)"), this);
    zoomOutAct->setShortcut(tr("Ctrl+-"));
    zoomOutAct->setEnabled(false);
    connect(zoomOutAct, SIGNAL(triggered()), this, SLOT(zoomOut()));
 
    normalSizeAct = new QAction(tr("&Normal Size"), this);
    normalSizeAct->setShortcut(tr("Ctrl+S"));
    normalSizeAct->setEnabled(false);
    connect(normalSizeAct, SIGNAL(triggered()), this, SLOT(normalSize()));
 
    fitToWindowAct = new QAction(tr("&Fit to Window"), this);
    fitToWindowAct->setEnabled(false);
    fitToWindowAct->setCheckable(true);
    fitToWindowAct->setShortcut(tr("Ctrl+F"));
    connect(fitToWindowAct, SIGNAL(triggered()), this, SLOT(fitToWindow()));
 
    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()));
}
//! [18]
 
//! [19]
void ImageViewer::createMenus()
//! [19] //! [20]
{
    fileMenu = new QMenu(tr("&File"), this);
    fileMenu->addAction(openAct);
    fileMenu->addAction(printAct);
    fileMenu->addSeparator();
    fileMenu->addAction(exitAct);
 
    viewMenu = new QMenu(tr("&View"), this);
    viewMenu->addAction(zoomInAct);
    viewMenu->addAction(zoomOutAct);
    viewMenu->addAction(normalSizeAct);
    viewMenu->addSeparator();
    viewMenu->addAction(fitToWindowAct);
 
    helpMenu = new QMenu(tr("&Help"), this);
    helpMenu->addAction(aboutAct);
    helpMenu->addAction(aboutQtAct);
 
    menuBar()->addMenu(fileMenu);
    menuBar()->addMenu(viewMenu);
    menuBar()->addMenu(helpMenu);
}
//! [20]
 
//! [21]
void ImageViewer::updateActions()
//! [21] //! [22]
{
    zoomInAct->setEnabled(!fitToWindowAct->isChecked());
    zoomOutAct->setEnabled(!fitToWindowAct->isChecked());
    normalSizeAct->setEnabled(!fitToWindowAct->isChecked());
}
//! [22]
 
//! [23]
void ImageViewer::scaleImage(double factor)
//! [23] //! [24]
{
    Q_ASSERT(imageLabel->pixmap());
    scaleFactor *= factor;
    imageLabel->resize(scaleFactor * imageLabel->pixmap()->size());
 
    adjustScrollBar(scrollArea->horizontalScrollBar(), factor);
    adjustScrollBar(scrollArea->verticalScrollBar(), factor);
 
    zoomInAct->setEnabled(scaleFactor < 3.0);
    zoomOutAct->setEnabled(scaleFactor > 0.333);
}
//! [24]
 
//! [25]
void ImageViewer::adjustScrollBar(QScrollBar *scrollBar, double factor)
//! [25] //! [26]
{
    scrollBar->setValue(int(factor * scrollBar->value()
                            + ((factor - 1) * scrollBar->pageStep()/2)));
}

    ui->labelImage->setBackgroundRole(QPalette::Base);
    ui->labelImage->setSizePolicy(QSizePolicy::Ignored, QSizePolicy::Ignored);
    ui->scrollArea->setBackgroundRole(QPalette::Dark);
    QPixmap pict(1200,1200); //Картинка для теста
    QPainter x(&pict);
    x.setBrush(Qt::red);
    x.drawRect(0,0,1200,1200);
    x.drawLine(200,200,600,600);
    ui->labelImage->setPixmap(pict);