from graphics import *
import struct, zlib

def foo(self, x,y):    # Image.getpixel
    pos = y*(self.size[0]*3+1) + 3*x+1  # each line has '\x00' prefix
    return struct.unpack('3B', self.pixels[pos:pos+3])
# add getpixel to class Image
foo.im_class = Image
foo.im_func = foo
Image.getpixel = foo

def enable(im):
    im.save('D:\\pixels.png', bpp=24, compression='no')
    f = open('D:\\pixels.png', 'rb')
    f.seek(8 +8+13+4)
    chunk = []
    while 1:
        n = struct.unpack('>L', f.read(4))[0]
        if n==0: break  # 'IEND' chunk
        f.read(4) # 'IDAT'
        chunk.append(f.read(n))
        f.read(4)   # CRC
    f.close()
    data = zlib.decompress(''.join(chunk))
    im.pixels = data    # data will be retrived by im.getpixel(x,y)