# coding: utf-8
import turtle
import math
def draw_polygon(aTurtle, size=50, n=3):
for i in xrange(n):
aTurtle.forward(size)
def draw_n_angle(aTurtle, size=50, num=5, color=None):
if color:
aTurtle.begin_fill()
aTurtle.fillcolor(color)
for i in xrange(num):
aTurtle.forward(size)
aTurtle.left(360.0/num)
aTurtle.forward(size)
aTurtle.right(2*360.0/num)
if color:
aTurtle.end_fill()
'''
绘制正n角形，默认为黄色
args:
aTurtle: turtle对象实例
size: int类型，正多角形的边长
n: int类型，是几角形
color: str， 图形颜色，默认不填色
'''
def draw_5_angle(aTurtle=None, start_pos=(0,0), end_pos=(0,10), radius=100, color=None):
aTurtle = aTurtle or turtle.Turtle()
size = radius * math.sin(math.pi/5)/math.sin(math.pi*2/5)
aTurtle.left(math.degrees(math.atan2(end_pos[1]-start_pos[1], end_pos[0]-start_pos[0])))
aTurtle.penup()
aTurtle.goto(start_pos)
aTurtle.fd(radius)
aTurtle.pendown()
aTurtle.right(math.degrees(math.pi*9/10))
draw_n_angle(aTurtle, size, 5, color)
''' 根据起始位置、结束位置和外接圆半径画五角星
args:
aTurtle: turtle对象实例
start_pos: int的二元tuple，要画的五角星的外接圆圆心
end_pos: int的二元tuple，圆心指向的位置坐标点
radius: 五角星外接圆半径
color: str， 图形颜色，默认不填色
'''
def draw_5_star_flag(times=20.0):
''' 绘制五星红旗
args:
times: 五星红旗的规格为30*20， times为倍数，默认大小为10倍， 即300*200
'''
width, height = 30*times, 20*times
# 初始化屏幕和海龟
window = turtle.Screen() #初始化屏幕
aTurtle = turtle.Turtle() #新建图像turtle实例
aTurtle.hideturtle() #隐藏箭头
aTurtle.speed(10) #设置速度
# 画红旗
aTurtle.penup()
aTurtle.goto(-width/2, height/2)
aTurtle.pendown()
aTurtle.begin_fill()
aTurtle.fillcolor('red')
aTurtle.fd(width)
aTurtle.right(90)
aTurtle.fd(height)
aTurtle.right(90)
aTurtle.fd(width)
aTurtle.right(90)
aTurtle.fd(height)
aTurtle.right(90)
aTurtle.end_fill()
# 画大星星
draw_5_angle(aTurtle, start_pos=(-10*times, 5*times), end_pos=(-10*times, 8*times), radius=3*times, color='yellow')
# 画四个小星星
stars_start_pos = [(-5, 8), (-3, 6), (-3, 3), (-5, 1)]
for pos in stars_start_pos:
draw_5_angle(aTurtle, start_pos=(pos[0]*times, pos[1]*times), end_pos=(-10*times, 5*times), radius=1*times, color='yellow')
# 点击关闭窗口
window.exitonclick()
if __name__ == '__main__':
draw_5_star_flag()
