plugin.js

function getPixel (x, y) {
    var pixels = Picture.getPixel(x, y),
        red    = pixels[0],
        green  = pixels[1],
        blue   = pixels[2];

    if (red > 128) {
        red /= 2;
        red += Math.random() * 0x33;
    } else {
        red *= 2;
    }

    if (green < 64 || green > 192) {
        green = Math.random() * 0xff;
    }

    if (green < red) {
        blue *= x / Picture.width;
    }

    return [red, green, blue];
}

pyv8.bash

#!/bin/bash

apt-get install scons libboost-python-dev libboost-all-dev
svn checkout http://v8.googlecode.com/svn/trunk/ v8
svn checkout http://pyv8.googlecode.com/svn/trunk/ pyv8
cd v8/
export V8_HOME=`pwd`
cd ../pyv8/
python setup.py build
python setup.py install

rm -R v8/
rm -R pyv8/

test.py

#!/bin/python

import PyV8
import png
from glob import glob
from math import floor


input_file = open("input.png", "rb")
input_source = png.Reader(file=input_file)
input_data = input_source.read()

width = input_data[0]
height = input_data[1]
pixel_data = list(input_data[2])

input_file.close()

def get_pixel(x, y):
    red = pixel_data[y][(x * 3) + 0]
    green = pixel_data[y][(x * 3) + 1]
    blue = pixel_data[y][(x * 3) + 2]

    return [red, green, blue]

def normalize (pixels):
    red   = pixels[0]
    green = pixels[1]
    blue  = pixels[2]

    red   = min(max(floor(red),   0x00), 0xff)
    green = min(max(floor(green), 0x00), 0xff)
    blue  = min(max(floor(blue),  0x00), 0xff)

    return [int(red), int(green), int(blue)]

class Global(PyV8.JSClass):
    def trace(self, message):
        print(message)

    Picture = {
        "width": width,
        "height": height,
        "getPixel": get_pixel,
    }

for plugin_filename in glob("./*.js"):
    plugin_file = open(plugin_filename, "r")
    plugin_source = plugin_file.read()
    plugin_file.close()

    filtered_pixel_data = pixel_data[:]

    def set_pixel(x, y, pixels):
        red, green, blue = normalize(pixels)

        filtered_pixel_data[y][(x * 3) + 0] = red
        filtered_pixel_data[y][(x * 3) + 1] = green
        filtered_pixel_data[y][(x * 3) + 2] = blue

    context = PyV8.JSContext(Global())
    context.enter()
    context.eval(plugin_source)

    for y in range(height):
        for x in range(width):
            set_pixel(x, y, context.locals['getPixel'](x, y))

    output_file = open(plugin_filename + ".png", "wb")
    output_source = png.Writer(width, height)
    output_source.write(output_file, pixel_data)
    output_file.close()

Dirty! \o/

In Zeile 52 musst Du deepcopy benutzen! Oh Mann, Raphael!