QPainter painter = new QPainter(this);
painter.fillRect(desktop.screenGeometry(screen), QColor.black);
QRect availGeo = desktop.availableGeometry(screen);
int x1 = (availGeo.width()/2)-(image.size().width()/2);
int y1 = (availGeo.height()/2)-(image.size().height()/2);
painter.drawImage(new QPoint(x1,y1), image);
}