message: group hide and show
diff: @@ -271,6 +271,18 @@ define(function (require) {
  return this;
  },
  + hide: function () {
  + for (var i = 0; i < this._children.length; i++) {
  + this._children[i].hide();
  + }
  + },
  +
  + show: function () {
  + for (var i = 0; i < this._children.length; i++) {
  + this._children[i].show();
  + }
  + },
  +
  /**
  * @return {module:zrender/core/BoundingRect}
  */
  