_calculateDimensions() {
      const cover = this.getDomRef();
      const scrollLeft = window.pageXOffset || document.documentElement.scrollLeft;
      const scrollTop = window.pageYOffset || document.documentElement.scrollTop;
      if (!cover) {
        return;
      }
      const domRef = this.getDomRef();
      const dotElement = domRef.querySelector(`.${CLOCK_MIDDOT_CLASS}`);
      const numberElement = domRef.querySelector(`.${CLOCK_NUMBER_CLASS}`);
      const radius = Math.round(cover.offsetHeight / 2);
      const dotHeight = this._outerHeight(dotElement);
      const numberHeight = this._outerHeight(numberElement);
      const offset = cover.getBoundingClientRect();
      this._dimensionParameters = {
        "radius": radius,
        "centerX": radius,
        "centerY": radius,
        "dotHeight": dotHeight,
        "numberHeight": numberHeight,
        "outerMax": radius,
        "outerMin": radius - numberHeight,
        "innerMax": radius - numberHeight - 1,
        "innerMin": radius - numberHeight * 2 - 1,
        "offsetX": offset.left + scrollLeft,
        "offsetY": offset.top + scrollTop
      };
    }
Calculates dimension variables necessary for determining of item selection.

@returns {TimePickerClockDimensions} Dimensions object