docs: function (data, clamp) {
          zrUtil.isArray(data) && (data = data[0]);
          clamp == null && (clamp = true);
  
          var dayInfo = this.getDateInfo(data);
          var range = this._rangeInfo;
          var date = dayInfo.formatedDate;
  
          // if not in range return [NaN, NaN]
          if (clamp && !(
              dayInfo.time >= range.start.time
              && dayInfo.time < range.end.time + PROXIMATE_ONE_DAY
          )) {
              return [NaN, NaN];
          }
  
          var week = dayInfo.day;
          var nthWeek = this._getRangeInfo([range.start.time, date]).nthWeek;
  
          if (this._orient === 'vertical') {
              return [
                  this._rect.x + week * this._sw + this._sw / 2,
                  this._rect.y + nthWeek * this._sh + this._sh / 2
              ];
  
          }
  
          return [
              this._rect.x + nthWeek * this._sw + this._sw / 2,
              this._rect.y + week * this._sh + this._sh / 2
          ];
  
      }