code: function tooltip() {
      var _this6 = this;
  
      var options = this.options,
          tooltipBox = this.tooltipBox,
          imageData = this.imageData;
  
  
      if (!this.viewed || this.played || !options.tooltip) {
        return this;
      }
  
      tooltipBox.textContent = Math.round(imageData.ratio * 100) + '%';
  
      if (!this.tooltipping) {
        if (options.transition) {
          if (this.fading) {
            dispatchEvent(tooltipBox, EVENT_TRANSITION_END);
          }
  
          addClass(tooltipBox, CLASS_SHOW);
          addClass(tooltipBox, CLASS_FADE);
          addClass(tooltipBox, CLASS_TRANSITION);
  
          // Force reflow to enable CSS3 transition
          // eslint-disable-next-line
          tooltipBox.offsetWidth;
          addClass(tooltipBox, CLASS_IN);
        } else {
          addClass(tooltipBox, CLASS_SHOW);
        }
      } else {
        clearTimeout(this.tooltipping);
      }
  
      this.tooltipping = setTimeout(function () {
        if (options.transition) {
          addListener(tooltipBox, EVENT_TRANSITION_END, function () {
            removeClass(tooltipBox, CLASS_SHOW);
            removeClass(tooltipBox, CLASS_FADE);
            removeClass(tooltipBox, CLASS_TRANSITION);
            _this6.fading = false;
          }, {
            once: true
          });
  
          removeClass(tooltipBox, CLASS_IN);
          _this6.fading = true;
        } else {
          removeClass(tooltipBox, CLASS_SHOW);
        }
  
        _this6.tooltipping = false;
      }, 1000);
  
      return this;
    }
docs: Show the current ratio of the image with percentage