import turtle
from random import random
from random import randint
def draw_petal(turtle_obj, flower):
# 绘制掉落的花瓣
for i in range(int(flower)):
# 有正有负就可以让画笔往二个方向走
x = flower - 4 * flower * random()
# 花瓣整体宽度(-10, 10)
y = 10 - 20 * random()
# 提笔，向前y，左转90，走x，落笔
turtle_obj.penup()
turtle_obj.forward(y)
turtle_obj.left(90)
turtle_obj.forward(x)
turtle_obj.pendown()
# 珊瑚色
turtle_obj.pencolor("lightcoral")
# 画圆
turtle_obj.circle(1)
# 回到起点
# 提笔，后退x，右转90,后退y，落笔
turtle_obj.penup()
turtle_obj.backward(x)
turtle_obj.right(90)
turtle_obj.backward(y)
turtle_obj.pendown()
# 画树枝部分
def draw_tree(turtle_obj, branch, tree_color):
# 设置一个最小分支长度
min_branch = 4
if branch > min_branch:
if branch < 8:
# 以0.5的概率，向左、右分支
if randint(0, 1) == 0:
# 左为白色
turtle_obj.pencolor("snow")
else:
# 右为珊瑚色
turtle_obj.pencolor("lightcoral")
# 枝干
turtle_obj.pensize(branch / 2)
elif 8 <= branch <= 16:
# 以0.33的概率，分为左、中、右分支
if randint(0, 2) == 0:
# 左为白色
turtle_obj.pencolor("snow")
else:
# 中、右为珊瑚色
turtle_obj.pencolor("lightcoral")
# 树枝
turtle_obj.pensize(branch / 4)
else:
# 褐色
turtle_obj.pencolor(tree_color)
# 细枝
turtle_obj.pensize(branch / 10)
# 最开始的树干长度
turtle_obj.forward(branch)
# 随机度数因子
a = 1.5 * random()
# 顺时针旋转随机角度（0～30度）
turtle_obj.right(20 * a)
# 随机长度因子
b = 1.5 * random()
# 往右画，直到画不动为止
draw_tree(turtle_obj, branch - 10 * b, tree_color)
# 左转随机角度
turtle_obj.left(40 * a)
# 往左画，直到画不动位置
draw_tree(turtle_obj, branch - 10 * b, tree_color)
# 右转一定角度
turtle_obj.right(20 * a)
# 提笔
turtle_obj.penup()
# 递归结束回到起点
turtle_obj.backward(branch)
turtle_obj.pendown()
def get_screen(width, height, color, speed):
# 创建画幕
screen_obj = turtle.Screen()
# 画布大小：(width, height)，颜色：color
screen_obj.screensize(width, height, bg=color)
screen_obj.setup(1.0, 1.0)
# speed倍加速
screen_obj.tracer(speed)
return screen_obj
def trees(tree_num):
# 颜色
color = ['brown', 'tan', 'black']
for j in range(tree_num):
# 树干颜色
tree_color = color[randint(0, len(color) - 1)]
# 画笔大小
pensize = randint(2, 5)
# 前进像素
forward = ((-1) ** pensize) * pensize * randint(20, 50)
# 后退像素
if pensize <= 3:
backward = ((-1) ** pensize) * (5 - pensize) * randint(10, 15)
else:
backward = pensize * randint(45, 50)
# 创建画笔
turtle_obj = turtle.Turtle()
# 画笔粗细
turtle_obj.pensize(pensize)
# 提笔，向前forward，左转90，backward，落笔
turtle_obj.penup()
turtle_obj.forward(forward)
turtle_obj.left(90)
turtle_obj.backward(backward)
turtle_obj.pendown()
# 画笔颜色：褐色
turtle_obj.pencolor(tree_color)
# 枝干粗细
branch = pensize * 15
# 落花数
flowers = branch
# 第j棵树
draw_tree(turtle_obj, branch, tree_color)
# 花瓣
draw_petal(turtle_obj, flowers)
if __name__ == '__main__':
# 创建画幕
my_screen_width = 800
my_screen_height = 600
my_screen_color = 'wheat'
my_screen_speed = 5
my_screen_obj = get_screen(my_screen_width, my_screen_height,
my_screen_color, my_screen_speed)
# 樱花树
# 棵数
my_tree_num = 5
trees(my_tree_num)
# 点击关闭画布
my_screen_obj.exitonclick()
