function (ecModel, api) {

        /**
         * @private
         * @type {module:echarts/data/Tree}
         */
        this._oldTree;

        /**
         * @private
         * @type {module:zrender/container/Group}
         */
        this._mainGroup = new graphic.Group();

        /**
         * @private
         * @type {module:echarts/componet/helper/RoamController}
         */
        this._controller = new RoamController(api.getZr());

        this._controllerHost = {target: this.group};

        this.group.add(this._mainGroup);
    }
function (ecModel, api) {

        /**
         * @private
         * @type {module:echarts/data/Tree}
         */
        this._oldTree;

        /**
         * @private
         * @type {module:zrender/container/Group}
         */
        this._mainGroup = new graphic.Group();

        /**
         * @private
         * @type {module:echarts/componet/helper/RoamController}
         */
        this._controller = new RoamController(api.getZr());

        this._controllerHost = {target: this.group};

        this.group.add(this._mainGroup);
    }
function ( ecModel , api ) { /**
         * @private
         * @type {module:echarts/data/Tree}
         */ this . _oldTree ; /**
         * @private
         * @type {module:zrender/container/Group}
         */ this . _mainGroup = new graphic . Group ( ) ; /**
         * @private
         * @type {module:echarts/componet/helper/RoamController}
         */ this . _controller = new RoamController ( api . getZr ( ) ) ; this . _controllerHost = { target : this . group } ; this . group . add ( this . _mainGroup ) ; }
Init the chart
@override
@param  {module:echarts/model/Global} ecModel
@param  {module:echarts/ExtensionAPI} api
Init the chart
A node that contains a node in the tree