Function make_wedged_bezier2

lib/matplotlib/bezier.py:642–690

Being similar to `get_parallels`, returns control points of two quadratic Bézier lines having a width roughly parallel to given one separated by *width*.

(bezier2, width, w1=1., wm=0.5, w2=0.)

def make_wedged_bezier2(bezier2, width, w1=1., wm=0.5, w2=0.):
    """
    Being similar to `get_parallels`, returns control points of two quadratic
    Bézier lines having a width roughly parallel to given one separated by
    *width*.
    """

    # c1, cm, c2
    c1x, c1y = bezier2[0]
    cmx, cmy = bezier2[1]
    c3x, c3y = bezier2[2]

    # t1 and t2 is the angle between c1 and cm, cm, c3.
    # They are also an angle of the tangential line of the path at c1 and c3
    cos_t1, sin_t1 = get_cos_sin(c1x, c1y, cmx, cmy)
    cos_t2, sin_t2 = get_cos_sin(cmx, cmy, c3x, c3y)

    # find c1_left, c1_right which are located along the lines
    # through c1 and perpendicular to the tangential lines of the
    # Bezier path at a distance of width. Same thing for c3_left and
    # c3_right with respect to c3.
    c1x_left, c1y_left, c1x_right, c1y_right = (
        get_normal_points(c1x, c1y, cos_t1, sin_t1, width * w1)
    )
    c3x_left, c3y_left, c3x_right, c3y_right = (
        get_normal_points(c3x, c3y, cos_t2, sin_t2, width * w2)
    )

    # find c12, c23 and c123 which are middle points of c1-cm, cm-c3 and
    # c12-c23
    c12x, c12y = (c1x + cmx) * .5, (c1y + cmy) * .5
    c23x, c23y = (cmx + c3x) * .5, (cmy + c3y) * .5
    c123x, c123y = (c12x + c23x) * .5, (c12y + c23y) * .5

    # tangential angle of c123 (angle between c12 and c23)
    cos_t123, sin_t123 = get_cos_sin(c12x, c12y, c23x, c23y)

    c123x_left, c123y_left, c123x_right, c123y_right = (
        get_normal_points(c123x, c123y, cos_t123, sin_t123, width * wm)
    )

    path_left = find_control_points(c1x_left, c1y_left,
                                    c123x_left, c123y_left,
                                    c3x_left, c3y_left)
    path_right = find_control_points(c1x_right, c1y_right,
                                     c123x_right, c123y_right,
                                     c3x_right, c3y_right)

    return path_left, path_right