code: static PdfAction createHide(PdfObject obj, boolean hide) {
          PdfAction action = new PdfAction();
          action.put(PdfName.S, PdfName.HIDE);
          action.put(PdfName.T, obj);
          if (!hide)
              action.put(PdfName.H, PdfBoolean.PDFFALSE);
          return action;
      }
docs: A Hide action hides or shows an object.
  @param obj object to hide or show
  @param hide true is hide, false is show
  @return a Hide Action