Hilbert Curve with Graphics.AST

Hilbert.hs

import Diagrams.AST

main = outputImage "hilbert.png" w w (hilbert i) where (i,w) = (8,1200)

hilbert i = Modifier (LineWidth 0.1) $ Shape $ Path Open $ Offsets (iterate build base !! i)

base = [(0,1),(1,0),(0,-1)]

build x = l $ n x ++ o ++ r (r (l (x ++ o ++ x) ++ o ++ n x))

o = [(1,0)]

l = map left
r = map right
n = reverse

left  (0,y) = (-y,0)
left  (x,0) = (0, x)

right (0,y) = (y, 0)
right (x,0) = (0,-x)