code: def handle_fractal():
      
  
      if check_etag():
          return flask.make_response(), 304
  
      level = int(flask.request.args.get("l", "0"))
      x = float(int(flask.request.args.get("x", "0")))
      y = float(int(flask.request.args.get("y", "0")))
  
      if level < 0:
          level = 0
  
      grid_size = math.pow(2, level)
  
      x0 = "%.30g" % ((x - 0) / grid_size)
      y0 = "%.30g" % ((y - 0) / grid_size)
      x1 = "%.30g" % ((x + 1) / grid_size)
      y1 = "%.30g" % ((y + 1) / grid_size)
  
      print "Tile: %s %s %s %s" % (x0, y0, x1, y1)
  
      width = str(CONF['width'])
      height = str(CONF['height'])
      iters = str(CONF['iters'])
  
      cmd = ['./mandelbrot', width, height, iters, x0, y0, x1, y1]
      image_data = subprocess.check_output(cmd)
  
      response = flask.make_response(image_data)
      response.headers["Content-Type"] = "image/png"
      response.headers["cache-control"] = "public, max-age=600"
      response.headers["ETag"] = ETAG
  
      return response
docs: Get fractal coordinates from query string, call mandelbrot to generate image.
  
      Returns:
          The image, wrapped in an HTML response.