# Diffusion Limited Aggregation fractal
# FB - 201004036
from PIL import Image
import random
import math
imgx = 256
imgy = 256
image = Image.new("L", (imgx, imgy))
# neighbor pixel directions
nx = [-1, -1, 0, 1, 1, 1, 0, -1]
ny = [0, 1, 1, 1, 0, -1, -1, -1]
maxIt = 256
xc = (imgx - 1) / 2
yc = (imgy - 1) / 2
rmax = min(xc, yc) - 1
# seed
image.putpixel((xc, yc), 255)
rm = 1.0
while rm < rmax:
a = random.random() * math.pi * 2.0
x = xc + rm * math.cos(a)
y = yc + rm * math.sin(a)
# random walk
flag = False
for i in range(maxIt):
a = random.randint(0, 7)
x = x + nx[a]
y = y + ny[a]
if x < 0 or x > (imgx - 1) or y < 0 or y > (imgy - 1):
break
if image.getpixel((x, y)) == 0:
# check the neighbors
for k in range(8):
xn = x + nx[k]
yn = y + ny[k]
if image.getpixel((xn, yn)) > 0:
image.putpixel((x, y), 255)
r = math.sqrt((x - xc) ** 2.0 + (y - yc) ** 2.0)
if r > rm:
rm = r
print "%" + str(int(100 * rm / rmax))
flag = True
break
if flag == True:
break
image.save("DLA.png", "PNG")
