最近在学Python，发现Python的海龟绘图非常有趣，就分享一下！
话不多说，先来Python turtle的官方文档链接： 。这里面有turtle的各类指令。turtle画国旗主要用到两个函数：draw_rentangle和draw_star。至于函数的调用就和我们学的C，C++是一样的。对于turtle画国旗的程序中，首先是查找国旗的画法，才能用程序实现。自己在实现的过程中主要是对turtle.circle（）没有准确掌握，所以花了一些不必要的时间。turtle.circle画弧时，海龟（turtle）的方向就是弧的切线方向，也就是说turtle的垂直方向就是圆心在的直线上，给定参数radius就可以画了，程序中第二注意的地方就是小五角星和大五角星的位置关系，主要是程序中的turtle.left（turtle.towards(center_x,center_y)-turtle.heading()）,当然，我看有的人用了round（）函数来获取近似值，但是，默认的已经足够了。下面是本人写的程序和结果演示。
程序：
import time
import turtle
import os
def draw_rectangle(start_x,start_y,rec_x,rec_y):
turtle.goto(start_x,start_y)
turtle.color('red')
turtle.fillcolor('red')
turtle.begin_fill()
for i in range(2):
turtle.forward(rec_x)
turtle.left(90)
turtle.forward(rec_y)
turtle.left(90)
turtle.end_fill()
def draw_star(center_x,center_y,radius):
turtle.setpos(center_x,center_y)
#find the peak of the five-pointed star
pt1=turtle.pos()
turtle.circle(-radius,72)
pt2=turtle.pos()
turtle.circle(-radius,72)
pt3=turtle.pos()
turtle.circle(-radius,72)
pt4=turtle.pos()
turtle.circle(-radius,72)
pt5=turtle.pos()
#draw the five-pointed star
turtle.color('yellow','yellow')
turtle.fill(True)
turtle.goto(pt3)
turtle.goto(pt1)
turtle.goto(pt4)
turtle.goto(pt2)
turtle.goto(pt5)
turtle.fill(False)
#start the project
turtle.speed(5)
turtle.penup()
#draw the rectangle
star_x=-320
star_y=-260
len_x=660
len_y=440
draw_rectangle(star_x,star_y,len_x,len_y)
#draw the big star
pice=660/30
big_center_x=star_x+5*pice
big_center_y=star_y+len_y-pice*5
turtle.goto(big_center_x,big_center_y)
turtle.left(90)
turtle.forward(pice*3)
turtle.right(90)
draw_star(turtle.xcor(),turtle.ycor(),pice*3)
#draw the small star
turtle.goto(star_x+10*pice,star_y+len_y-pice*2)
turtle.left(turtle.towards(big_center_x,big_center_y)-turtle.heading())
turtle.forward(pice)
turtle.right(90)
draw_star(turtle.xcor(),turtle.ycor(),pice)
#draw the second star
turtle.goto(star_x+pice*12,star_y+len_y-pice*4)
turtle.left(turtle.towards(big_center_x,big_center_y)-turtle.heading())
turtle.forward(pice)
turtle.right(90)
draw_star(turtle.xcor(),turtle.ycor(),pice)
#draw the third
turtle.goto(star_x+pice*12,star_y+len_y-7*pice)
turtle.left(turtle.towards(big_center_x,big_center_y)-turtle.heading())
turtle.forward(pice)
turtle.right(90)
draw_star(turtle.xcor(),turtle.ycor(),pice)
#draw the final
turtle.goto(star_x+pice*10,star_y+len_y-9*pice)
turtle.left(turtle.towards(big_center_x,big_center_y)-turtle.heading())
turtle.forward(pice)
turtle.right(90)
draw_star(turtle.xcor(),turtle.ycor(),pice)
turtle.ht()
time.sleep(3)
os._exit(1)
结果：
用Python的turtle模块画国旗
感觉画的还不赖
Ubuntu 14.04安装Python 3.3.5
CentOS上源码安装Python3.4
《Python核心编程 第二版》.(Wesley J. Chun ).[高清PDF中文版]