1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
|
# example based on article in BYTE magazine
# 4 bugs starting in separate corners of a square
# walk towards each other (this is also the picture on the cover)
# November 1982
# p. 236 - 240
from wrappers import Turtle
import wx
def draw(canvas):
t = Turtle(canvas)
t.cls()
# create four bugs and send them to the four corners of a square
bug1 = Turtle(canvas)
bug1.color('magenta')
bug1.st()
bug1.pu()
bug1.rt(45)
bug1.fd(300)
bug1.pd()
bug2 = Turtle(canvas)
bug2.color('green')
bug2.st()
bug2.pu()
bug2.rt(135)
bug2.fd(300)
bug2.pd()
bug3 = Turtle(canvas)
bug3.color('blue')
bug3.st()
bug3.pu()
bug3.rt(225)
bug3.fd(300)
bug3.pd()
bug4 = Turtle(canvas)
bug4.color('orange')
bug4.st()
bug4.pu()
bug4.rt(315)
bug4.fd(300)
bug4.pd()
# bug1 is added at the end of the list as a convenience
bList = [bug1, bug2, bug3, bug4, bug1]
# speed up drawing time
tempAutoRefresh = canvas.autoRefresh
canvas.autoRefresh = 0
# the bugs take 400 "steps" toward each other
for i in range(430):
# orient each bug towards its neighbor
# by doing this separately from
# the step forward, we don't need to maintain
# state in a separate list
for b in range(4):
h = bList[b].towards(bList[b + 1])
bList[b].setHeading(h)
# each bug takes one step forward
for b in range(4):
bList[b].fd(1)
canvas.refresh()
if wx.Platform == '__WXMAC__':
canvas.redraw()
canvas.autoRefresh = tempAutoRefresh
for b in range(4):
bList[b].ht()
|
