turtle 实现clip_rule代码

以下是Python中使用turtle模块实现clip_rule的代码示例：

import turtle

# 定义点集
points = [(100, 50), (50, 100), (-50, 100), (-100, 50), (-100, -50), (-50, -100), (50, -100), (100, -50)]

# 定义裁剪窗口
clip_window = [(0, 0), (0, 200), (200, 200), (200, 0)]

# 定义裁剪规则
def clip_rule(point1, point2, clip_point):
    x1, y1 = point1
    x2, y2 = point2
    x_min, y_min = clip_point[0]
    x_max, y_max = clip_point[2]
    dx = x2 - x1
    dy = y2 - y1

    # 判断点是否在裁剪窗口内
    def inside(x, y):
        return x_min <= x <= x_max and y_min <= y <= y_max

    if dx == 0 and dy == 0:  # 点
        if inside(x1, y1):
            return [(x1, y1)]
        else:
            return []
    elif dx == 0:  # 垂直线
        if (y1 < y_min and y2 < y_min) or (y1 > y_max and y2 > y_max):
            return []
        elif y1 < y_min:
            return [(x1, y_min), (x2, y_max)]
        else:
            return [(x1, y_max), (x2, y_min)]
    elif dy == 0:  # 水平线
        if (x1 < x_min and x2 < x_min) or (x1 > x_max and x2 > x_max):
            return []
        elif x1 < x_min:
            return [(x_min, y1), (x_max, y2)]
        else:
            return [(x_max, y1), (x_min, y2)]
    else:  # 斜线
        m = dy / dx
        b = y1 - m * x1
        intersections = []
        if inside(x1, m * x1 + b):
            intersections.append((x1, m * x1 + b))
        if inside((y1 - b) / m, y1):
            intersections.append(((y1 - b) / m, y1))
        if inside(x2, m * x2 + b):
            intersections.append((x2, m * x2 + b))
        if inside((y2 - b) / m, y2):
            intersections.append(((y2 - b) / m, y2))
        if len(intersections) == 2:
            return intersections
        else:
            return []

# 绘制点集
def draw_points(points):
    turtle.penup()
    for point in points:
        turtle.goto(point)
        turtle.pendown()
        turtle.dot()
    turtle.penup()

# 绘制裁剪窗口
def draw_clip_window(clip_window):
    turtle.penup()
    turtle.goto(clip_window[0])
    turtle.pendown()
    for point in clip_window:
        turtle.goto(point)
    turtle.goto(clip_window[0])
    turtle.penup()

# 绘制裁剪后的图形
def draw_clipped_shape(points, clip_window):
    clipped_points = []
    for i in range(len(points)):
        j = (i + 1) % len(points)
        clipped_points.extend(clip_rule(points[i], points[j], clip_window))

    turtle.penup()
    turtle.goto(clipped_points[0])
    turtle.pendown()
    for point in clipped_points:
        turtle.goto(point)
    turtle.goto(clipped_points[0])
    turtle.penup()

# 初始化画布
turtle.setup(500, 500)
turtle.title("Clip Rule")

# 绘制点集和裁剪窗口
draw_points(points)
draw_clip_window(clip_window)

# 绘制裁剪后的图形
draw_clipped_shape(points, clip_window)

# 隐藏画笔
turtle.hideturtle()

# 显示画布
turtle.done()

运行以上代码，将会在turtle画布中绘制出点集、裁剪窗口和裁剪后的图形。