Game of Life Visualization

gol.py

#!/usr/bin/env python

# description: Game of Life Visualization
# author: Nicolas Seriot
# idea: https://twitter.com/JacobJoaquin/status/923681854254825473
# typical outout: http://seriot.ch/visualization/gol.gif

from PIL import Image, ImageDraw
from images2gif import writeGif

import random

NB_STEPS = 16
GRID_SIZE = 16
CELL_SIZE = 64
DENSITY = 0.3

def create_grid(N=24):
    return [[0]*N for i in xrange(N)]

def fill_grid_randomly(g, density=0.5):

    for x,y in [(x,y) for y in range(len(g)) for x in range(len(g[y]))]:
        g[y][x] = 1 if random.uniform(0.0, 1.0) < density else 0

    return g

def nb_neighbnours(grid, x, y):
    
    size = len(grid)
    
    W = (size + x-1) % size
    E = (size + x+1) % size
    N = (size + y-1) % size
    S = (size + y+1) % size
    
    return sum([grid[N][W], grid[N][x], grid[N][E],
                grid[y][W],             grid[y][E],
                grid[S][W], grid[S][x], grid[S][E]])
    
def next(g):

    new_grid = create_grid(N=len(g))
    
    for x,y in [(x,y) for y in range(len(g)) for x in range(len(g[y]))]:

        n = nb_neighbnours(g, x, y)

        if (g[y][x] == 0 and n == 3) or (g[y][x] == 1 and n in [2,3]):
            new_grid[y][x] = 1
                        
    return new_grid

def draw_grid(g, img, i):

    draw = ImageDraw.Draw(img)
        
    for x,y in [(x,y) for y in range(len(g)) for x in range(len(g[y])) if g[y][x] == 1]:

        x1, x2 = CELL_SIZE + CELL_SIZE*x + 2*i, 2*CELL_SIZE + CELL_SIZE*x - 2*i
        y1, y2 = CELL_SIZE + CELL_SIZE*y + 2*i, 2*CELL_SIZE + CELL_SIZE*y - 2*i
        draw.ellipse((x1, y1, x2, y2), fill = "white", outline ='black')

def main():
    
    g = create_grid(N=GRID_SIZE)
    fill_grid_randomly(g, density=DENSITY)
    
    images = []

    img = Image.new('RGB', (len(g)*CELL_SIZE + 2*CELL_SIZE, len(g)*CELL_SIZE + 2*CELL_SIZE), "white")
    
    for num_gen in range(NB_STEPS):

        draw_grid(g, img, num_gen)

        images.append(img)

        g = next(g)

        img = img.copy()
    
    writeGif("gol.gif", images, duration=0.25)

if __name__ == "__main__":
    main()