import math
def draw_polygon(aTurtle, size=50, n=3):
''' 绘制正多边形
args:
aTurtle: turtle对象实例
size: int类型，正多边形的边长
n: int类型，是几边形
'''
for i in range(n):
aTurtle.forward(size)
aTurtle.left(360.0 / n)
def draw_n_angle(aTurtle, size=50, num=5, color=None):
''' 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
'''
if color:
aTurtle.begin_fill()
aTurtle.fillcolor(color)
for i in range(num):
aTurtle.forward(size)
aTurtle.left(360.0 / num)
aTurtle.forward(size)
aTurtle.right(2 * 360.0 / num)
if color:
aTurtle.end_fill()
def draw_5_angle(aTurtle=None, start_pos=(0, 0), end_pos=(0, 10), radius=100, color=None):
''' 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
'''
aTurtle = aTurtle or turtle.Turtle()
# size = radius * math.sin(math.pi/5)/math.sin(math.pi*2/5)计算公式错误，但不影响显示
size = radius * math.sin(math.pi / 5) / math.sin(math.pi * 3 / 10) # 修正
angle = math.degrees(math.atan2(end_pos[1] - start_pos[1], end_pos[0] - start_pos[0]))
print(angle)
aTurtle.penup()
aTurtle.goto(start_pos)
aTurtle.setheading(0)
aTurtle.left(angle)
aTurtle.fd(radius)
aTurtle.pendown()
aTurtle.right(math.degrees(math.pi * 9 / 10))
draw_n_angle(aTurtle, size, 5, color)
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()
window.title("五星红旗~")
aTurtle = turtle.Turtle()
aTurtle.hideturtle()
aTurtle.speed(10)
# 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()
