python学习之绘图

from turtle import *

colormode(255)

lt(90)

lv = 14
l = 120
s = 45

width(lv)

r = 0
g = 0
b = 0
pencolor(r, g, b)

penup()
bk(l)
pendown()
fd(l)

def draw_tree(l, level):
global r, g, b
# save the current pen width
w = width()

# narrow the pen width
width(w * 3.0 / 4.0)
# set color:
r = r + 1
g = g + 2
b = b + 3
pencolor(r % 200, g % 200, b % 200)

l = 3.0 / 4.0 * l

lt(s)
fd(l)

if level < lv:
    draw_tree(l, level + 1)
bk(l)
rt(2 * s)
fd(l)

if level < lv:
    draw_tree(l, level + 1)
bk(l)
lt(s)

# restore the previous pen width
width(w)

speed(“fastest”)

draw_tree(l, 4)

done()