import Tkinter as tk

 from caugrid import Grid

 class Render(object):

 	def __init__(self, title, width, height):

 		self.title = title		

 		self.width = width

 		self.height = height

 		self.root = tk.Tk(className=title, sync=1)

 		self.canvas = tk.Canvas(width=self.width, height=self.height, bg="black")

 		self.canvas.pack(expand=tk.YES, fill=tk.BOTH)

 	def render(self, grid):

 		offset = (self.width / 2, self.height / 2)

 		size = 1

 		cell_ids = []

 		for pos in grid.cells.iterkeys():

 			x = pos[0] + offset[0]

 			y = pos[1] + offset[1]

 			cell_id = self.canvas.create_rectangle(x, y, x+size, y+size, 

 					fill="yellow", width=0)

 			cell_ids.append(cell_id)

 		self.root.update()

 		for cell_id in cell_ids:

 			self.canvas.delete(cell_id)

 import sys

 import time

 import caumarshal as marshal

 import os, stat

 def main():

 	filename = sys.argv[1]

 	print "rendering ", filename	

 	render = Render("hope", 1000, 1000)

 	mod_time = 0

 	while True:

 		current = os.stat(filename)[stat.ST_MTIME]

 		if current > mod_time:

 			mod_time = current

 			print "updating render"

 			try:

 				grid = marshal.loadGrid(filename)

 				render.render(grid)

 			except IndexError, ValueError:

 				print "loading error"

 		time.sleep(1)

 if __name__ == "__main__":

 	main()