#!/usr/bin/ruby

#
## http://rosettacode.org/wiki/Barnsley_fern
#

require('Imager')

var w = 640
var h = 640

var img = %s<Imager>.new(xsize => w, ysize => h, channels => 3)
var green = %s<Imager::Color>.new('#00FF00')

var (x, y) = (float(0), float(0))

for r in (^1e4 -> lazy.map { 100.irand }) {
  (x, y) = (
    if    (r <=  1) { ( 0.00*x - 0.00*y,  0.00*x + 0.16*y + 0.00) }
    elsif (r <=  8) { ( 0.20*x - 0.26*y,  0.23*x + 0.22*y + 1.60) }
    elsif (r <= 15) { (-0.15*x + 0.28*y,  0.26*x + 0.24*y + 0.44) }
    else            { ( 0.85*x + 0.04*y, -0.04*x + 0.85*y + 1.60) }
  )
  img.setpixel(x => w/2 + 60*x, y => 60*y, color => green)
}

img.flip(dir => 'v')
img.write(file => 'barnsleyFern.png')