code: def get_scroll_info(event):
      
      direction = None
      if event.direction == gtk.gdk.SCROLL_UP:
          direction = 0.0
      elif event.direction == gtk.gdk.SCROLL_DOWN:
          direction = 180.0
      elif event.direction == gtk.gdk.SCROLL_LEFT:
          direction = 270.0
      elif event.direction == gtk.gdk.SCROLL_RIGHT:
          direction = 90.0
  
      # TODO: does Gtk encode the amount of scroll?
      # 15 deg is standard 1-click turn for a wheel mouse
      degrees = 15.0
  
      return (degrees, direction)
docs: Returns the (degrees, direction) of a scroll motion Gtk event.