code: Rectangle getBoxSize(String boxName) {
      	PdfRectangle r = (PdfRectangle)thisBoxSize.get(boxName);
      	if (r != null) return r.getRectangle();
      	return null;
      }
docs: Gives the size of a trim, art, crop or bleed box, or null if not defined.
  @param boxName crop, trim, art or bleed