layout(settings) {
    if (settings) {
      this._layout = new layout(settings);

      this._layout.spread(settings.spread, this.settings.minSpreadWidth); // this.mapping = new Mapping(this._layout.props);


      this._layout.on(constants["c" /* EVENTS */].LAYOUT.UPDATED, (props, changed) => {
        this.emit(constants["c" /* EVENTS */].RENDITION.LAYOUT, props, changed);
      });
    }

    if (this.manager && this._layout) {
      this.manager.applyLayout(this._layout);
    }

    return this._layout;
  }
Adjust the layout of the rendition to reflowable or pre-paginated
@param  {object} settings