import random
import math
from PIL import Image
import matplotlib

cmap = matplotlib.cm.get_cmap('viridis') # or Paired

imgx = 400
imgy = 300
image = Image.new("RGB", (imgx, imgy))

n=160
nx = [];ny = []; nr = []; ng = []; nb = []
for i in range(n):
    nx.append(random.randint(0, imgx - 1))
    ny.append(random.randint(0, imgy - 1))
    r,g,b,a = cmap(i/n)
    nr.append(int(r*255))
    ng.append(int(g*255))
    nb.append(int(b*255))
    
for y in range(imgy):
    for x in range(imgx):
        # find the closest cell center
        dmin = math.hypot(imgx - 1, imgy - 1)
        j = -1
        for i in range(n):
            d = math.hypot(nx[i] - x, ny[i] - y)
            if d < dmin:
                dmin = d
                j = i
        image.putpixel((x, y), (nr[j], ng[j], nb[j]))
for i in range(n):
    image.putpixel((nx[i], ny[i]),(nr[i], ng[i], nb[i]))

image.save("./fig1.png", "PNG")
image.show()