scheme_primitives.py 文件源码

def tscheme_circle(r, extent=None):
    """Draw a circle with center R units to the left of the turtle (i.e.,
    right if N is negative.  If EXTENT is not None, then draw EXTENT degrees
    of the circle only.  Draws in the clockwise direction if R is negative,
    and otherwise counterclockwise, leaving the turtle facing along the
    arc at its end."""
    if extent is None:
        _check_nums(r)
    else:
        _check_nums(r, extent)
    _tscheme_prep()
    turtle.circle(r, extent and extent)
    return okay