#include <QtGui>
#include <QtWidgets>
#include <QApplication>

class Widget : public QWidget
{
public:
    Widget(QWidget *parent = 0) : QWidget(parent) {}

protected:
    void paintEvent(QPaintEvent *)
    {
        QLinearGradient v = QLinearGradient(QPointF(0,0), QPointF(0,1));
        v.setCoordinateMode(QGradient::ObjectBoundingMode);

        QLinearGradient h = QLinearGradient(QPointF(0,0), QPointF(1,0));
        h.setCoordinateMode(QGradient::ObjectBoundingMode);

        QBrush vBrush(v);
        QBrush hBrush(h);

        QPainter painter(this);

        QPen p = painter.pen();
        p.setWidth(25);

        p.setBrush(vBrush);
        painter.setPen(p);
        painter.drawLine(QPointF(100,100),QPointF( 99,200));
        painter.drawLine(QPointF(200,200),QPointF(200,100));
        painter.drawLine(QPointF(300,100),QPointF(301,200));

        p.setBrush(hBrush);
        painter.setPen(p);
        painter.drawLine(QPointF(400,100),QPointF(500, 99));
        painter.drawLine(QPointF(400,200),QPointF(500,200));
        painter.drawLine(QPointF(400,300),QPointF(500,301));
    }
};

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

    Widget * widget = new Widget;
    widget->setWindowTitle("QLinearGradient");
    widget->showMaximized();

    return a.exec();
}