python绘制彩虹图教程

from turtle import *
  
#控制彩虹路径
def path(pen, r, g, b):
 pen.penup()
 pen.goto(-400, -300)
 pen.pendown()
 pen.pencolor(r, g, b)
 pen.circle(1000, -180)
 pen.pensize(2)
 pen.right(0.05)
  
#绘制彩虹控制颜色
def Rainbow():
 pen = Turtle()
 pen.right(110)
 r = 255
 g = 0
 b = 0
 interval = 5
 colormode(255)
 # 由红到黄
 while g < 256:
  path(pen, r, g, b)
  g = g + interval
 #由黄到绿
 g = 255
 while r > 0:
  r = r - interval
  path(pen, r, g, b)
 #由绿到青
 r = 0
 while (b < 255 ):
  b = b + interval
  path(pen, r, g, b)
 b = 255
 #由青到蓝
 while (g > 0):
  g = g - interval
  path(pen, r, g, b)
 #由蓝到紫到红
 g = 0
 while r < 255:
  r = r + interval
  path(pen, r, g, b)
  
#文字输出
def TextFun():
 text = Turtle()
 text.hideturtle()
 text.color("red")
 text.penup()
 text.setpos(100, -100)
 text.pendown()
 text.write("Rainbow", False, align="center", font=("Script MT Bold", 80, "bold"))
  
def main():
 setup(800, 600, 0, 0)
 title("rainbow")
 tracer(False)
 Rainbow()
 TextFun()
 tracer(True)
 mainloop()
  
if __name__ == '__main__':
 main()