Fill Demo

# a quick fill demo by anthony cook fb.com/groups/pygame
# use the left mouse button to draw a shape
# use the right mouse button to fill

import pygame

class fill:
    class node:
        def __init__(s, parent, x, y):
            global W, H
            for xx in range(x, W):
                if parent.pixelArray[xx, y] != parent.replacedColor:
                    xx -= 1
                    break
            s.x = xx
            s.y = y
            s.parent = parent

        def do(s):
            global W, H

            topNode = 0
            bottomNode = 0
            newNodes = []

            for x in range(s.x, 0, -1):
                if s.y - 1 > 0:
                    if s.parent.pixelArray[x][s.y - 1] == s.parent.replacedColor:
                        if topNode == 0:
                            newNodes.append([x, s.y - 1])
                            topNode = 1
                    elif s.parent.pixelArray[x][s.y - 1] != s.parent.replacedColor and topNode == 1:
                        topNode = 0

                s.parent.pixelArray[x, s.y] = s.parent.newColor
                if s.parent.pixelArray[x - 1, s.y] != s.parent.replacedColor:
                    break

                if s.y + 1 <= H:
                    if s.parent.pixelArray[x][s.y + 1] == s.parent.replacedColor:
                        if bottomNode == 0:
                            newNodes.append([x, s.y + 1])
                            bottomNode = 1
                    elif s.parent.pixelArray[x][s.y + 1] != s.parent.replacedColor and bottomNode == 1:
                        bottomNode = 0
            return newNodes


    def __init__(s, surface, x, y, color):
        s.pixelArray = pygame.PixelArray(surface)
        s.replacedColor = s.pixelArray[x][y]
        if color == s.replacedColor:
            s.pixelArray.close()
            del s.pixelArray
            return
        s.newColor = color
        s.nodes = [s.node(s, x, y)]
        while s.nodes:
            newNodes = []
            for n in s.nodes:
                newNodes += n.do()
            s.nodes = [s.node(s, xy[0], xy[1]) for xy in newNodes]

        s.pixelArray.close()
        del s.pixelArray

W, H = 1280, 720
HW, HH = 640, 360

pygame.init()
DS = pygame.display.set_mode((W, H))

FILL_COLOR = DS.map_rgb((255, 0, 0))

mousePressed = False

# press ESC to exit demo
while True:
    e = pygame.event.get()
    if pygame.key.get_pressed()[pygame.K_ESCAPE]: break

    mb = pygame.mouse.get_pressed()
    mx, my = pygame.mouse.get_pos()
    if mb[0] and not mousePressed:
        px, py = mx, my
        mousePressed = True
    if mousePressed:
        if not mb[0]: mousePressed = False
        pygame.draw.line(DS, (255, 255, 255), (px, py), (mx, my))
        px, py = mx, my

    if mb[2]:
        fill(DS, mx, my, FILL_COLOR)

    pygame.display.update()

pygame.quit()