Is there a way turtle-graphics lets us change the fill color?

Question

I want to make a scenery with this code of fractals, and I need the fill color to change every second. I've tried a for-loop to redraw the whole thing, but that interferes with the other parts of my code that shouldn't be repeated

Is there a way turtle-graphics lets us change the fill color?

from turtle import *
from time import sleep, perf_counter
tracer(0)
def hilbert(size, level, parity):
    if level == 0:
        return
    left(parity * 90)
    hilbert(size, level - 1, -parity)
    forward(size)
    right(parity * 90)
    hilbert(size, level - 1, parity)
    forward(size)
    hilbert(size, level - 1, parity)
    right(parity * 90)
    forward(size)
    hilbert(size, level - 1, -parity)
    left(parity * 90)
def fractal(dist, depth, dir):
    if depth < 1:
        fd(dist)
        return
    fractal(dist / 3, depth - 1, dir)
    lt(60 * dir)
    fractal(dist / 3, depth - 1, dir)
    rt(120 * dir)
    fractal(dist / 3, depth - 1, dir)
    lt(60 * dir)
    fractal(dist / 3, depth - 1, dir)
reset()
speed(0)
ht()
pu()
size = 6

setpos(-33*size, -32*size)
pd()
fillcolor("chocolate")
begin_fill()
fd(size)

hilbert(size, 6, 1)

fd(size)
for i in range(3):
    lt(90)
    fd(size*(64+i%2))
pu()
for i in range(2):
    fd(size)
    rt(90)
pd()
for i in range(4):
    fd(size*(66+i%2))
    rt(90)
end_fill()
update()

Output:

Although `from turtle import *` is fine for short explanatory examples, for larger programs like this it is considered bad Python programming to use a wildcard import. — cdlane, May 22 '20 at 21:48
Ann, despite the time I spend worrying about turtles, I was not aware of that folder (it's buried eight directory levels deep under /Library on OSX.) Thanks for the pointer! Clearly spooky similarities on the Hilbert code but some of these examples might help answer common SO questions, e.g two_canvases.py, paint.py and forest.py. It took me a while to discover the examples built into turtle.py itself, if you *run* it rather than use it as a library. All of these examples put together should be seen by folks before they pass judgement on what Python turtle "can and can't do". What fun! — cdlane, May 23 '20 at 04:26
Ann, folks often try to *embed* turtle in a tkinter canvas the wrong way, so this provides an example of how to go about it. And having two turtle canvases is just a small step away from having two turtle windows at the same time! — cdlane, May 24 '20 at 17:14

score 1 · Accepted Answer · answered May 22 '20 at 21:47

Encapsulating the drawing code in functions, and adding a timer, behind the scenes we can redraw it every second with a different background color. This leaves you free to use the turtle to draw other things while the background color changes:

from turtle import Screen, Turtle
from itertools import cycle

COLORS = ['chocolate', 'tomato', 'plum', 'salmon', 'bisque', 'lime', 'olive', 'wheat']

size = 6

def hilbert(t, size, level, parity=1):
    if level == 0:
        return

    t.left(parity * 90)
    hilbert(t, size, level - 1, -parity)
    t.forward(size)
    t.right(parity * 90)
    hilbert(t, size, level - 1, parity)
    t.forward(size)
    hilbert(t, size, level - 1, parity)
    t.right(parity * 90)
    t.forward(size)
    hilbert(t, size, level - 1, -parity)
    t.left(parity * 90)

def filled_hilbert(t, color):
    t.clear()
    t.setheading(0)

    t.penup()
    t.setposition(-33 * size, -32 * size)
    t.pendown()

    t.fillcolor(next(color))
    t.begin_fill()

    t.forward(size)

    hilbert(t, size, 6, 1)

    t.forward(size)

    for i in range(3):
        t.left(90)
        t.forward(size * (64 + i % 2))

    t.penup()

    for i in range(2):
        t.forward(size)
        t.right(90)

    t.pendown()

    for i in range(4):
        t.forward(size * (66 + i % 2))
        t.right(90)

    t.end_fill()

    screen.update()

    screen.ontimer(lambda: filled_hilbert(t, color), 1000)

screen = Screen()
screen.tracer(0)

turtle = Turtle()
turtle.hideturtle()

filled_hilbert(turtle, cycle(COLORS))

screen.mainloop()

However, any turtle that's drawing comes to the front, so this image won't necessarily stay in the background unless you synchronize your forground drawing with it.

Is there a way turtle-graphics lets us change the fill color?

1 Answers1