Method transmute

lib/matplotlib/patches.py:3843–3899

(self, path, mutation_size, linewidth)

            super().__init__()

        def transmute(self, path, mutation_size, linewidth):
            # docstring inherited
            x0, y0, x1, y1, x2, y2 = self.ensure_quadratic_bezier(path)

            # divide the path into a head and a tail
            head_length = self.head_length * mutation_size
            in_f = inside_circle(x2, y2, head_length)
            arrow_path = [(x0, y0), (x1, y1), (x2, y2)]

            try:
                arrow_out, arrow_in = \
                    split_bezier_intersecting_with_closedpath(arrow_path, in_f)
            except NonIntersectingPathException:
                # if this happens, make a straight line of the head_length
                # long.
                x0, y0 = _point_along_a_line(x2, y2, x1, y1, head_length)
                x1n, y1n = 0.5 * (x0 + x2), 0.5 * (y0 + y2)
                arrow_in = [(x0, y0), (x1n, y1n), (x2, y2)]
                arrow_out = None

            # head
            head_width = self.head_width * mutation_size
            head_left, head_right = make_wedged_bezier2(arrow_in,
                                                        head_width / 2., wm=.5)

            # tail
            if arrow_out is not None:
                tail_width = self.tail_width * mutation_size
                tail_left, tail_right = get_parallels(arrow_out,
                                                      tail_width / 2.)

                patch_path = [(Path.MOVETO, tail_right[0]),
                              (Path.CURVE3, tail_right[1]),
                              (Path.CURVE3, tail_right[2]),
                              (Path.LINETO, head_right[0]),
                              (Path.CURVE3, head_right[1]),
                              (Path.CURVE3, head_right[2]),
                              (Path.CURVE3, head_left[1]),
                              (Path.CURVE3, head_left[0]),
                              (Path.LINETO, tail_left[2]),
                              (Path.CURVE3, tail_left[1]),
                              (Path.CURVE3, tail_left[0]),
                              (Path.LINETO, tail_right[0]),
                              (Path.CLOSEPOLY, tail_right[0]),
                              ]
            else:
                patch_path = [(Path.MOVETO, head_right[0]),
                              (Path.CURVE3, head_right[1]),
                              (Path.CURVE3, head_right[2]),
                              (Path.CURVE3, head_left[1]),
                              (Path.CURVE3, head_left[0]),
                              (Path.CLOSEPOLY, head_left[0]),
                              ]

            path = Path([p for c, p in patch_path], [c for c, p in patch_path])

            return path, True