code: def rendered_text(self):
          
          if len(self._plain_images) <= 0:
              self._convert_images()
  
          if self._animation is None:
              index = self._index
              self._index += 1
              if self._index >= len(self._plain_images):
                  self._index = 0
          else:
              index = self._animation()
          return (self._plain_images[index],
                  self._colour_map[index])
docs: :return: The next image and colour map in the sequence as a tuple.