def relqbezier(self, x1, y1, x, y):
        self.path.append(
            'q' + str(x1) + ',' + str(y1) + ' ' + str(x) + ',' + str(y))
quadratic bezier with xy1 to xy relative
dataset/ETHPy150Open CGATOxford/cgat/CGAT/SVGdraw.py/pathdata.relqbezier