code: public static Rectangle grow (Rectangle source, Rectangle target)
      {
          if (target == null) {
              log.warning("Can't grow with null rectangle [src=" + source + ", tgt=" + target + "].",
                          new Exception());
          } else if (source == null) {
              source = new Rectangle(target);
          } else {
              source.add(target);
          }
          return source;
      }
docs: Adds the target rectangle to the bounds of the source rectangle. If the source rectangle is
  null, a new rectangle is created that is the size of the target rectangle.
  
  @return the source rectangle.