autoItemWidth (autoItemWidth) {
        if (!arguments.length) {
            return this._autoItemWidth;
        }
        this._autoItemWidth = autoItemWidth;
        return this;
    }
Turn automatic width for legend items on or off. If true, {@link Legend#itemWidth itemWidth} is ignored.
This setting takes into account the {@link Legend#gap gap}.
@param  {Boolean} [autoItemWidth=false]
@returns {Boolean|Legend}