void YourWidget:

aintEvent(QPaintEvent *){
QPainter painter( this );
QRect rect(0,0,100,200);
QPointF startPoint(rect.x(),rect.y());
QPointF stopPoint(rect.x(),rect.y()+rect.height());
QLinearGradient fade;
fade.setStart(startPoint);
fade.setFinalStop(stopPoint );
fade.setColorAt( 0.0, QColor(0xf2,0x48,0xa0,0xc0));
fade.setColorAt( 0.5, QColor(0xe2,0x41,0x92,0xc0));
fade.setColorAt( 1.0, QColor(0xbc,0x21,0x6d,0xc0) );
QPen pen;
pen.setColor(QColor(0xff,0xff,0xff));
pen.setWidth(2);
QBrush brush=QBrush(fade);
painter.setPen(pen);
painter.setBrush(brush);
painter.drawRoundedRect(rect.x(),rect.y(), rect.width(), rect.height(),10,10);
}