code: function(location, placement) {
              var options = $.isPlainObject(location) ? location : {
                  location: location,
                  placement: placement
              };
              this._init({
                  location: options.location || this.location,
                  placement: options.placement !== undefined ?
                      options.placement : this.placement,
                  onDraw: options.onDraw || this.onDraw,
                  checkResize: options.checkResize || this.checkResize,
                  width: options.width !== undefined ? options.width : this.width,
                  height: options.height !== undefined ? options.height : this.height,
                  rotationMode: options.rotationMode || this.rotationMode
              });
          }
docs: Changes the overlay settings.
  @function
  @param {OpenSeadragon.Point|OpenSeadragon.Rect|Object} location
  If an object is specified, the options are the same than the constructor
  except for the element which can not be changed.
  @param {OpenSeadragon.Placement} placement