code: function (zoomLevel, redraw) {
              this._zoomLevel = zoomLevel / 100;
  
              if (this._keepCenter) {
                  this.centerImage(false);
              }
  
              if (redraw === true) {
                  this.redraw();
              }
          }
docs: Set zoom by percent
  
  @param zoomLevel
  @param redraw