code: function getHitLineWidth() {
      var attrs = this._attrs;
      // if (!attrs.stroke) {
      //   return 0;
      // }
      var lineAppendWidth = attrs.lineAppendWidth || 0;
      var lineWidth = attrs.lineWidth || 0;
      return lineWidth + lineAppendWidth;
    }
docs: 获取拾取时线的宽度，需要考虑附加的线的宽度