QT draw a rotated line with arrows

Tesb::tesb (Qwidget *parent): Qwidget (parent) {UI.SETUPUI (this);}  void Tesb::D rawcustomline (qpainter& _painter, double _angle, double _len, const qstring& _name, const qcolor& _color) {//Initialize _painter.resettransform ();//Reset Brush _painter.translate (Qpoint (300,300)); _painter.setpen (QPen (Qt:: Black, 2));//Draw Segment Qline _line (Qpoint (0,0), Qpoint (_len,0)); _painter.rotate (_angle); _painter.drawline (_line);// Draw arrow int off_x = 10; Qpainterpath _path;_path.moveto (_len-off_x,-5); _path.lineto (_len,0); _path.lineto (_len-off_x,5); _ Painter.drawpath (_path);//Draw name _painter.setpen (_color); Qfont _font = _painter.font (); _font.setpointsize; _font.setbold (true); _painter.setfont (_font); _ Painter.drawtext (Qpoint (_len-2*off_x,-10), _name);} void Tesb::p aintevent (qpaintevent *ev) {qpainter _painter (this); _painter.setpen (Qpen (Qt::black, 2));//Anti-aliasing _ Painter.setrenderhint (qpainter::antialiasing);//Move the Brush center point to (300,300) _painter.translate (Qpoint (300,300));//Draw Center Point _ Painter.drawpoint (Qpoint (0,0));//Draw an outer circle _painter.drawelliPSE (Qrect ( -150,-150,300,300));D rawcustomline (_painter, 0, Max, "Da", qt::red);D rawcustomline (_painter, 123.5, 130, " Db ", Qt::green);D rawcustomline (_painter, -45," Dc ", Qt::blue);D rawcustomline (_painter, -145," Dd ", Qt::yellow); Qwidget::p aintevent (EV);}

QT draw a rotated line with arrows