code: function(items) {
              for(var i = 0; i < items.length; i++) {
                  var height = items[i].element[0].getBoundingClientRect().height;
                  var relPosDiff = items[i].diffWithNextRelativePos;
                  var ratio = 0;
                  if(!isNaN(height) && !isNaN(relPosDiff))
                      ratio = height / relPosDiff;
  
                  items[i].relativePosRatio = ratio;
              }
          }
docs: Method that calculates ratio: item's height / relative pos diff with next item