#!/usr/bin/python
import Image, sys, string

if len(sys.argv) not in [6,7]:
	print "Usage: chromakey inimage outimage r g b [distance]"
	sys.exit(1)

inimg = Image.open(sys.argv[1]).convert('RGB')
outimg = inimg.convert('RGBA')
bgcolor = (string.atoi(sys.argv[3]), string.atoi(sys.argv[4]), string.atoi(sys.argv[5]))
if len(sys.argv) == 7:
    maxdistance = string.atoi(sys.argv[6])
else:
    maxdistance = 0

maxdistanceSquared = maxdistance * maxdistance

def distanceSquared(a,b):
    d0 = a[0] - b[0]
    d1 = a[1] - b[1]
    d2 = a[2] - b[2]
    return d0*d0 + d1*d1 + d2*d2

for x in range(0,inimg.size[0]):
  for y in range(0,inimg.size[1]):
    color = inimg.getpixel((x,y))
    if distanceSquared(color,bgcolor) <= maxdistanceSquared:
        outimg.putpixel((x,y), (color[0], color[1], color[2], 0))

outimg.save(sys.argv[2])