docs: def get_unit_name(self, surf, name, radius):
      """Get a length limited unit name for drawing units."""
      key = (name, radius)
      if key not in self._name_lengths:
        max_len = surf.world_to_surf.fwd_dist(radius * 1.6)
        for i in range(len(name)):
          if self._font_small.size(name[:i + 1])[0] > max_len:
            self._name_lengths[key] = name[:i]
            break
        else:
          self._name_lengths[key] = name
      return self._name_lengths[key]