shape.py 文件源码

def __init__(self, start, point=None, vector=None):
        "Create a line or line segment"
        self.pos = start
        if point:
            ux = point[0] - start[0]
            uy = point[1] - start[1]
        elif type(vector) in (int, float):
            ux = 1
            uy = vector
        else: ux, uy = vector
        self._size = abs(ux), abs(uy)
        u = hypot(ux, uy)
        self.length = u #if point else None
        self.u = ux / u, uy / u