_getSecondary() {
    let currZoomLevel = this._parseZoomLevelOption('secondary');

    if (currZoomLevel) {
      return currZoomLevel;
    } // 3x of "fit" state, but not larger than original


    currZoomLevel = Math.min(1, this.fit * 3);

    if (this.elementSize && currZoomLevel * this.elementSize.x > MAX_IMAGE_WIDTH) {
      currZoomLevel = MAX_IMAGE_WIDTH / this.elementSize.x;
    }

    return currZoomLevel;
  }
Get zoom level to which image will be zoomed after double-tap gesture,
or when user clicks on zoom icon,
or mouse-click on image itself.
If you return 1 image will be zoomed to its original size.

@private
@return {number}