@Override
  public Map<String, String> getTransferableOptions() {
    final HashMap<String, String> map = new HashMap<>();
    map.put(BACKGROUND_VISIBLE_OPTION, String.valueOf(backgroundVisible));
    map.put(GRID_VISIBLE_OPTION, String.valueOf(gridVisible));
    map.put(ZOOM_FACTOR_OPTION, String.valueOf(zoomFactor));
    map.put(ZOOM_FACTOR_CHANGED_OPTION, String.valueOf(zoomFactorChanged));
    return map;
  }
@Override
  public Map<String, String> getTransferableOptions()