usrbinenv python3 turtleexamplesuite tdemopaint py a simple eventdriven paint program left mouse button moves turtle middle mouse button changes color right mouse button toggles between pen up no line drawn when the turtle moves and pen down line is drawn if pen up follows at least two pendown moves the polygon that includes the starting point is filled play around by clicking into the canvas using all three mouse buttons to exit press stop button usr bin env python3 turtle example suite tdemo_paint py a simple event driven paint program left mouse button moves turtle middle mouse button changes color right mouse button toggles between pen up no line drawn when the turtle moves and pen down line is drawn if pen up follows at least two pen down moves the polygon that includes the starting point is filled play around by clicking into the canvas using all three mouse buttons to exit press stop button
from turtle import *

def switchupdown(x=0, y=0):
    if pen()["pendown"]:
        end_fill()
        up()
    else:
        down()
        begin_fill()

def changecolor(x=0, y=0):
    global colors
    colors = colors[1:]+colors[:1]
    color(colors[0])

def main():
    global colors
    shape("circle")
    resizemode("user")
    shapesize(.5)
    width(3)
    colors=["red", "green", "blue", "yellow"]
    color(colors[0])
    switchupdown()
    onscreenclick(goto,1)
    onscreenclick(changecolor,2)
    onscreenclick(switchupdown,3)
    return "EVENTLOOP"

if __name__ == "__main__":
    msg = main()
    print(msg)
    mainloop()