# file: stripes.py
#
# date: Oct. 25, 2007
#
# author: Bob Muller, CS074 Digital World; Fall 2007
#
# This file contains a few simple python functions that use the turtle
# graphics system to draw colored stripes across the turtle window.
#
import turtle

def setup(w, h):
	turtle.setup(width=w, height=h)
	turtle.degrees()
	turtle.up()

# stripe accepts the y coordinate of a stripe, the height of a stripe and
# its color.
#
def stripe(y, stripeHeight, color):

	turtle.color(color)

	windowWidth = turtle.window_width()

	right = windowWidth / 2
	left = - right

	turtle.goto(left, y)

	turtle.begin_fill()
	turtle.goto(right, y)
	turtle.goto(right, y + stripeHeight)
	turtle.goto(left, y + stripeHeight)
	turtle.goto(left, y)

	turtle.end_fill()

# stripes accepts the number of stripes required and two alternating
# colors. Once stripes.setup has been called, stripes can be called as in:
#
# stripes.stripes(10,'Blue','Green')
#
def stripes(n, color1, color2):

	windowHeight = turtle.window_height()

	top = windowHeight / 2
	bottom = - top

	stripeHeight = windowHeight / n

	y = top - stripeHeight

	colorFlag = True

	while y >= bottom:

		if colorFlag:
			stripe(y, stripeHeight, color1)
		else:
			stripe(y, stripeHeight, color2)

		y = y - stripeHeight

		colorFlag = not(colorFlag)