import turtle, math

width = 400
height = 400

# set up the screen to use coordinates I like
# 8 pixels of padding all around the main coordinate system (for aesthetics)
# (-8,-8) is in the upper left corner so that (0,0) is in a nice space.
# one pixel is equal to one 'turtle' unit.
def mysetup():
	global sc,t
	pad = 8
	screenw = width + 2*pad
	screenh = height + 2*pad
	turtle.setup(width=screenw, height=screenh) #make the window a good size
	turtle.resizemode('noresize')
	sc = turtle.getscreen()
	sc.setworldcoordinates(-1*pad, screenh, screenw, -1*pad) #set up my coordinates.
	sc.colormode(255) #color values range from 0 to 255 (inclusive)
	t = turtle.getturtle()
	t.speed(0)
	t.penup()
	t.hideturtle()
	sc.tracer(0,0) #speed up animation homeboy

# tried to make this as fast as possible,
# while still being able to specify size in pixels
def draw_rect(pos, sz=10, color='black', fill=False): #3 default values.
	x = pos[0]
	y = pos[1]
	t.color(color)
	t.shape('square')
	if fill:
		t.begin_fill()
	t.goto(x,y)
	t.pendown()
	t.goto(x + sz, y)
	t.goto(x+sz, y+sz)
	t.goto(x, y+sz)
	t.goto(x,y)
	t.penup();
	if fill:
		t.end_fill()

# https://krazydad.com/tutorials/makecolors.php
def prettyColor(k):
	pi = math.pi #so I don't have to keep typing 'math'
	def s(o, x): #inner function
		mag = 255
		minbright = 128
		return int(mag/2*(math.sin(o + 1/3*x)) + minbright)
	return s(0, k), s(pi*2/3, k), s(4*pi/3, k)

# Call this function to draw the picture
def main():
        mysetup()
        sz = 10
        for c in range(width * height // sz**2):
                x = c % (width // sz)
                y = c // (width // sz)
                draw_rect((x*sz,y*sz), sz = sz, color=prettyColor(c), fill=True)
        sc.update() #update screen
        sc.exitonclick()

main()