#include <QApplication>
#include <QLabel>
#include <QPainter>


QPixmap createPixmap()
{
    QPolygon polygon;
    polygon << QPoint(70, -351)
            << QPoint(170, -251)
            << QPoint(503, -19)
            << QPoint(503, 217);

    QImage image(800, 300, QImage::Format_RGB32);

    QPainter painter(&image);
    painter.setPen(QPen(Qt::white, 2));
    painter.drawPolyline(polygon);
    painter.setPen(QPen(Qt::red, 0));
    painter.drawPolyline(polygon);
    painter.end();

    return QPixmap::fromImage(image);
}


int main(int argc, char** argv)
{
    QApplication app(argc, argv);

    QLabel label;
    label.setPixmap(createPixmap());
    label.show();

    return app.exec();
}