_getNextPositions(items) {
    // If position data is going to be changed, add the item's size to the
    // transformer to allow for calculations.
    if (this.options.isCentered) {
      const itemsData = items.map((item, i) => {
        const itemSize = Shuffle.getSize(item.element, true);
        const point = this._getItemPosition(itemSize);
        return new Rect(point.x, point.y, itemSize.width, itemSize.height, i);
      });

      return this.getTransformedPositions(itemsData, this.containerWidth);
    }

    // If no transforms are going to happen, simply return an array of the
    // future points of each item.
    return items.map((item) => this._getItemPosition(Shuffle.getSize(item.element, true)));
  }
Return an array of Point instances representing the future positions of
each item.
@param {ShuffleItem[]} items Array of sorted shuffle items.
@return {Point[]}
@private