applyCurrentZoomPan() {
    this._applyZoomTransform(this.pan.x, this.pan.y, this.currZoomLevel);

    if (this === this.pswp.currSlide) {
      this.pswp.dispatch('zoomPanUpdate', {
        slide: this
      });
    }
  }
Apply transform and scale based on
the current pan position (this.pan) and zoom level (this.currZoomLevel)