gistfile1.py

def is_black(p):
	return (p[0] | p[1] | p[2]) == 0


class FlatImage:
	def __init__(self, path):
		self.image = Image.open(path)
		self.labels = [[0]*100]*100
		self.pix = self.image.load()
		self.flat = []

	def west(self, x, y):
		if (x == 0):
			return (0, 0, 0, 0)
		else:
			return self.pix[x-1, y]

	def north(self, x, y):
		if (y == 0):
			return (0, 0, 0, 0)
		else:
			return self.pix[x, y-1]

	def find_areas(self):
		linked = {0: {0}}
		NextLabel = 1
		for y in xrange(100):
			for x in xrange(100):
				dbg = x == 0 and y >= 20
				if is_black(self.pix[x, y]):
					self.labels[x][y] = 0
					continue

				nl = set()
				if not is_black(self.west(x, y)):
					nl.add(self.labels[x-1][y])
				if not is_black(self.north(x, y)):
					nl.add(self.labels[x][y-1])

				if len(nl) == 0:
					self.labels[x][y] = NextLabel
					linked[NextLabel] = {NextLabel}
					NextLabel = NextLabel + 1
				elif len(nl) == 1:
					self.labels[x][y] = nl.pop()
					if dbg:
						print x, y, self.labels[x][y]
				else:
					self.labels[x][y] = min(nl)
					l1 = nl.pop()
					l2 = nl.pop()
					union = linked[l1].union(linked[l2])
#					print "Linking", linked[l1], "and", linked[l2], "into", union
					for l in union:
						linked[l] = union

				if self.labels[x][y] == 0:
					print x, y, self.pix[x, y], self.west(x, y), self.north(x, y)
					raise "Wat?"