Python使用Turtle绘制分形树

1 '''
2 作者：清扬
3 功能：利用递归绘制分型树
4 版本：1.0
5 日期：2020/02/25
6 '''
7 
8 importturtle
9 
10 defdraw_branch(branch_length):
11     '''
12 绘制分型树
13 :param branch_length:
14 :return:
15     '''
16     if branch_length > 5:
17         if branch_length > 10:
18             turtle.pensize(10)
19             turtle.color('brown')
20         else:
21             turtle.pensize(5)
22             turtle.color('green')
23 
24         #绘制右侧树枝
25 turtle.forward(branch_length)
26 
27 
28         print('向前',branch_length)
29         turtle.right(20)
30         print('右转 20')
31         draw_branch(branch_length-15)
32 
33         #绘制左侧树枝
34         turtle.left(40)
35         print('左转 40')
36         draw_branch(branch_length-15)
37 
38         #返回之前的树枝上
39         print('右转 20')
40         turtle.right(20)
41 
42 turtle.penup()
43 turtle.backward(branch_length)
44 turtle.pendown()
45 
46         print('向后',branch_length)
47 
48 defmain():
49     '''
50 主函数
51     '''
52     turtle.left(90)
53 turtle.penup()
54     turtle.backward(200)
55 turtle.pendown()
56     turtle.color('brown')
57     print('左转 90')
58     turtle.speed(5000)
59     draw_branch(100);
60     turtle.exitonclick() 
61 
62 if __name__ == '__main__':
63     main()