神奇！教你如何用Python来画树
古人有诗云“庭中有奇树，绿叶发华滋”，树之美，或婀娜、或繁茂、或苍劲、或青翠。python-turtle笔下的树更是别有一番风味。
01 小园新种红樱树，闲绕花行便当游
# coding=gbk
import turtle as T
import random
import time
# 画樱花的躯干(60,t)
def Tree(branch, t):
time.sleep(0.0005)
if branch > 3:
if 8 <= branch <= 12:
if random.randint(0, 2) == 0:
t.color(‘snow’) # 白
else:
t.color(‘lightcoral’) # 淡珊瑚色
t.pensize(branch / 3)
elif branch < 8:
if random.randint(0, 1) == 0:
t.color(‘snow’)
else:
t.color(‘lightcoral’) # 淡珊瑚色
t.pensize(branch / 2)
else:
t.color(‘sienna’) # 赭(zhě)色
t.pensize(branch / 10) # 6
t.forward(branch)
a = 1.5 * random.random()
t.right(20 * a)
b = 1.5 * random.random()
Tree(branch - 10 * b, t)
t.left(40 * a)
Tree(branch - 10 * b, t)
t.right(20 * a)
t.up()
t.backward(branch)
t.down()
# 掉落的花瓣
def Petal(m, t):
for i in range(m):
a = 200 - 400 * random.random()
b = 10 - 20 * random.random()
t.up()
t.forward(b)
t.left(90)
t.forward(a)
t.down()
t.color(‘lightcoral’) # 淡珊瑚色
t.circle(1)
t.up()
t.backward(a)
t.right(90)
t.backward(b)
# 绘图区域
t = T.Turtle()
# 画布大小
w = T.Screen()
# 隐藏画笔
t.hideturtle()
t.getscreen().tracer(5, 0)
# wheat小麦
w.screensize(bg=‘white’)
t.left(90)
t.up()
t.backward(150)
t.down()
t.color(‘sienna’)
# 画樱花的躯干
Tree(60, t)
# 掉落的花瓣
Petal(200, t)
w.exitonclick()
02 江南有丹橘，经冬犹绿林
# coding=gbk
from turtle import *
from random import *
from math import *
class Tree:
def init(self):
setup(1000, 500)
bgcolor(1, 1, 1) # 背景色
# ht() # 隐藏turtle
speed(10) # 速度 1-10渐进，0 最快
# tracer(1, 100) # 设置绘图屏幕刷新频率，参数1设置在正常刷新频次的第参数1次刷新，参数2设置每次刷新的时延
tracer(0, 0)
pu() # 抬笔
backward(100)
# 保证笔触箭头方向始终不向下，此处使其左转90度，而不是右转
left(90) # 左转90度
backward(300) # 后退300
def tree(self, n, l):
pd() # 下笔
# 阴影效果
t = cos(radians(heading() + 45)) / 8 + 0.25
pencolor(t, t, t)
pensize(n / 1.2)
forward(l) # 画树枝
if n > 0:
b = random() * 15 + 10 # 右分支偏转角度
c = random() * 15 + 10 # 左分支偏转角度
d = l * (random() * 0.25 + 0.7) # 下一个分支的长度
# 右转一定角度,画右分支
right(b)
self.tree(n - 1, d)
# 左转一定角度，画左分支
left(b + c)
self.tree(n - 1, d)
# 转回来
right©
else:
# 画叶子
right(90)
n = cos(radians(heading() - 45)) / 4 + 0.5
pencolor(n, n * 0.8, n * 0.8)
fillcolor(n, n * 0.8, n * 0.8)
begin_fill()
circle(3)
left(90)
end_fill()
# 添加0.3倍的飘落叶子
if random() > 0.7:
pu()
# 飘落
t = heading()
an = -40 + random() * 40
setheading(an)
dis = int(800 * random() * 0.5 + 400 * random() * 0.3 + 200 * random() * 0.2)
forward(dis)
setheading(t)
# 画叶子
pd()
right(90)
n = cos(radians(heading() - 45)) / 4 + 0.5
pencolor(n * 0.5 + 0.5, 0.4 + n * 0.4, 0.4 + n * 0.4)
fillcolor(n, n * 0.8, n * 0.8)
begin_fill()
circle(2)
left(90)
end_fill()
pu()
# 返回
t = heading()
setheading(an)
backward(dis)
setheading(t)
# pass
pu()
backward(l) # 退回
def main():
tree = Tree()
tree.tree(12, 100) # 递归7层
done()
if name == ‘main’:
main()
03 落红不是无情物,化作春泥更护花
# coding=gbk
from turtle import *
from random import *
# 画树方法
def drawTree(n, l):
pendown()
pencolor(‘#5d3c3c’)
pensize( n / 1.5)
forward(l)
if n > 0:
dr = randint(30, 40)
dl = randint(30, 40)
move = l * (random() * 0.4 + 0.5)
right(dr)
drawTree(n - 1, move)
left(dr + dl)
drawTree(n - 1, move)
right(dl)
else:
drawPetal(3)
penup()
backward(l)
# 花瓣位置生成
def petalPlace(m, x, y):
penup()
goto(x, y)
pendown()
setheading(0)
tracer(False)
for i in range(m):
if i == 0:
drawPetal(5)
else:
penup()
goto(x, y)
a = randint(20, 400)
b = randint(-50, 50)
forward(a)
left(90)
forward(b)
right(90)
pendown()
drawPetal(5)
# 花朵绘画方法
def drawPetal(n):
colormode(255)
r = randint(200, 255)
g = randint(8, 158)
b = randint(8, 158)
begin_fill()
fillcolor(r, g, b)
pencolor(r, g, b)
circle(n)
end_fill()
# 启动方法
def run():
setup(1.0, 1.0)
penup()
goto(-50, -150)
left(90)
pendown()
hideturtle()
tracer(False)
drawTree(13, 150)
petalPlace(160, -100, -150)
run()
done()
04 川原秋色静，芦苇晚风鸣
import turtle
import random
stack = []
defcreateWord(max_it, word, proc_rules, x, y, turn):
turtle.up()
turtle.home()
turtle.goto(x, y)
turtle.right(turn)
turtle.down()
t = 0
while t < max_it:
word = rewrite(word, proc_rules)
drawit(word, 5, 20)
t = t+1
defrewrite(word, proc_rules):
wordList = list(word)
for i in range(len(wordList)):
curChar = wordList[i]
if curChar in proc_rules:
wordList[i] = proc_rules[curChar]
return “”.join(wordList)
defdrawit(newWord, d, angle):
newWordLs = list(newWord)
for i in range(len(newWordLs)):
cur_Char = newWordLs[i]
if cur_Char == ‘F’:
turtle.forward(d)
elif cur_Char == ‘+’:
turtle.right(angle)
elif cur_Char == ‘-’:
turtle.left(angle)
elif cur_Char == ‘[’:
state_push()
elif cur_Char == ‘]’:
state_pop()
defstate_push():
global stack
stack.append((turtle.position(), turtle.heading()))
defstate_pop():
global stack
position, heading = stack.pop()
turtle.up()
turtle.goto(position)
turtle.setheading(heading)
turtle.down()
defrandomStart():
x = random.randint(-300, 300)
y = random.randint(-320, -280)
heading = random.randint(-100, -80)
return ((x, y), heading)
defmain():
rule_sets = []
rule_sets.append(((3, 5), ‘F’, {‘F’:‘F[+F][-F]F’}))
rule_sets.append(((4, 6), ‘B’, {‘B’:‘F[-B][+ B]’, ‘F’:‘FF’}))
rule_sets.append(((2, 4), ‘F’, {‘F’:‘FF+[+F-F-F]-[-F+F+F]’}))
tree_count = 50
turtle.tracer(10, 0)
for x in range(tree_count):
rand_i = random.randint(0, len(rule_sets) - 1)
selected_ruleset = rule_sets[rand_i]
i_range, word, rule = selected_ruleset
low, high = i_range
i = random.randint(low, high)
start_position, start_heading = randomStart()
start_x, start_y = start_position
createWord(i, word, rule, start_x, start_y, start_heading)
if name == ‘main’: main()
上面代码都可以直接执行，感兴趣就去试试吧！
