opt: pl_gallery layout

lib/plugin/pl_gallery/interactiveviewer_gallery.dart

@@ -234,7 +234,8 @@ class _InteractiveviewerGalleryState extends State<InteractiveviewerGallery>
 
   @override
   Widget build(BuildContext context) {
-    return InteractiveViewerBoundary(
+    return Stack(children: [
+      InteractiveViewerBoundary(
         controller: _transformationController,
         boundaryWidth: MediaQuery.of(context).size.width,
         onScaleChanged: _onScaleChanged,
@@ -243,8 +244,7 @@ class _InteractiveviewerGalleryState extends State<InteractiveviewerGallery>
         onNoBoundaryHit: _onNoBoundaryHit,
         maxScale: widget.maxScale,
         minScale: widget.minScale,
-      child: Stack(children: [
-        CustomDismissible(
+        child: CustomDismissible(
           onDismissed: () {
             Navigator.of(context).pop();
             widget.onDismissed?.call(_pageController!.page!.floor());
@@ -275,6 +275,7 @@ class _InteractiveviewerGalleryState extends State<InteractiveviewerGallery>
             },
           ),
         ),
+      ),
       Positioned(
         bottom: 0,
         left: 0,
@@ -287,10 +288,7 @@ class _InteractiveviewerGalleryState extends State<InteractiveviewerGallery>
                   gradient: LinearGradient(
                     begin: Alignment.topCenter,
                     end: Alignment.bottomCenter,
-                      colors: [
-                        Colors.transparent,
-                        Colors.black.withOpacity(0.3)
-                      ],
+                    colors: [Colors.transparent, Colors.black.withOpacity(0.3)],
                   ),
                 )
               : null,
@@ -320,8 +318,7 @@ class _InteractiveviewerGalleryState extends State<InteractiveviewerGallery>
           ),
         ),
       ),
-      ]),
-    );
+    ]);
   }
 
   // 图片分享