code: function(curCoord, finalCoord) {
          this.logger.log("getNextX: " + curCoord + ", " + finalCoord);
          var t = this.thumb,
              thresh,
              tmp = [],
              nextCoord = null;
  
          if (curCoord[0] > finalCoord[0]) {
              thresh = t.tickSize - this.thumbCenterPoint.x;
              tmp = t.getTargetCoord( curCoord[0] - thresh, curCoord[1] );
              nextCoord = [tmp.x, tmp.y];
          } else if (curCoord[0] < finalCoord[0]) {
              thresh = t.tickSize + this.thumbCenterPoint.x;
              tmp = t.getTargetCoord( curCoord[0] + thresh, curCoord[1] );
              nextCoord = [tmp.x, tmp.y];
          } else {
              // equal, do nothing
          }
  
          return nextCoord;
      }
docs: Returns the next X tick value based on the current coord and the target coord.
  @method _getNextX
  @private