#include <QtGui>

#if (QT_VERSION >= QT_VERSION_CHECK(5, 0, 0))
#include <QtWidgets>
#endif

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);

    QGraphicsView view;

    QGraphicsScene *scene = new QGraphicsScene();
    view.setScene(scene);

    QImage image("ima600x800_original.png");
    qreal blur = 41;

    // render to QImage
    QPainter painter;
    painter.begin(&image);
    QGraphicsPixmapItem *pixmap = new QGraphicsPixmapItem ( QPixmap::fromImage(image), 0 );
    // apply the blur effect
    QGraphicsBlurEffect effect;
    effect.setBlurHints(QGraphicsBlurEffect::QualityHint); // PerformanceHint = 0x00, QualityHint = 0x01,
    effect.setBlurRadius(blur);
    pixmap->setGraphicsEffect(&effect);
    // add and render to scene
    scene->addItem(pixmap);
    scene->render(&painter);

    view.show();

    return a.exec();
}