anchor.diff:    /// Mirror to [PhotoView.gaplessPlayback]
     final bool gaplessPlayback;
   
  +  /// Mirror to [PageView.reverse]
  +  final bool reverse;
  +
     /// An object that controls the [PageView] inside [PhotoViewGallery]
     final PageController pageController;
   
  
positive.code:     this.backgroundDecoration,
      this.gaplessPlayback = false,
      this.customSize,
      this.pageController,
      this.onPageChanged,
      this.scaleStateChangedCallback,
  
negative.code:   @override
    Widget build(BuildContext context) {
      return PageView.builder(
        reverse: widget.reverse,
        controller: _controller,
        onPageChanged: widget.onPageChanged,
        itemCount: itemCount,
  