Flood Fill Algorithm Python

Question

So I\'m trying to create a flood fill algorithm and I keep getting a recursion error with this. The algorithm seems to have infinite recursion and I cannot pinpoint why. I

Answer 1

This has not been tested but is based mostly off the code you provided. It should work and provides an alternative method of implementing the floodfill algorithm. The function could be more efficient.

import PIL
import random
import collections

WHITE = 255, 255, 255
BLACK = 0, 0, 0
RED = 255, 0, 0

def main(width, height):
    flood = PIL.Image.new('RGB', (width, height), BLACK)
    # Create randomly generated walls
    for x in range(width):
        for y in range(height):
            flood.putpixel((x, y), BLACK if random.random() < 0.15 else WHITE)
    # Create borders
    for x in range(width):
        for y in range(height):
            if x in {0, width - 1} or y in {0, height - 1}:
                flood.putpixel((x, y), BLACK)
    floodfill(50, 25, RED, image)
    # Save image
    image.save('flood.png')

def floodfill(x, y, color, image):
    # if starting color is different from desired color
    #     create a queue of pixels that need to be changed
    #     while there are pixels that need their color changed
    #         change the color of the pixel to what is desired
    #         for each pixel surrounding the curren pixel
    #             if the new pixel has the same color as the starting pixel
    #                 record that its color needs to be changed
    source = image.getpixel((x, y))
    if source != color:
        pixels = collections.deque[(x, y)]
        while pixels:
            x, y = place = pixels.popleft()
            image.putpixel(place, color)
            for x_offset in -1, 1:
                x_offset += x
                for y_offset in -1, 1:
                    y_offset += y
                    new_place = x_offset, y_offset
                    if image.getpixel(new_place) == source:
                        pixels.append(new_place)

if __name__ == '__main__':
    main(100, 50)