"""

Boolean operations and Bezier paths.

This program makes swiss cheese by cutting out circles from another

circle. It demonstrates the use of boolean operations on paths.

"""

size(300, 300)

# First, create the "cheese" -- the central circle in the middle.

# But don't plot it yet, since we will be creating a new path

# with holes poked out of it.

cheese = arc(WIDTH/2, HEIGHT/2, 130, plot=False)

# Instead of the circle, we could use any arbitrary path.

# Try uncommenting the following lines to use a letter:

# font("Helvetica","bold", 400)

# cheese = textpath("S", 7, 291)

# Punch ten holes in the cheese

for i in range(10):

# Make a circle somewhere on the canvas, with a random size.

x = random(WIDTH)

y = random(HEIGHT)

sz = random(10, 60)

c = arc(x, y, sz, plot=False)

# Now comes the central part: create a new path out of the cheese

# that is the difference between the cheese and the newly created

# circle. Save this in cheese (overwriting the old value).

cheese = cheese.difference(c, 0.1)

# Another cool effect is to mirror the cutouts. Here, we create a

# mirrored copy of the circle, then cut it out of the cheese

# as well. (You might want to change the number of punchouts.)

# mx = WIDTH - x

# c = arc(mx, y, sz, plot=False)

# cheese = cheese.difference(c, 0.1)

# Now that the cheese is ready, draw it. First we pass it to the

# bezier() command with a dark fill color to draw a "shadow".

fill(0.1)

bezier(cheese)

# Once the shadow is drawn, translate the canvas a bit and draw the

# path again in glorious yellow:

translate(-3, -3)

fill(1, 0.9, 0.1, 0.8)

bezier(cheese)