opt.: server tab navigation bar when landscape

lib/view/widget/auto_hide.dart

@@ -0,0 +1,102 @@
+import 'dart:async';
+
+import 'package:flutter/material.dart';
+
+final class AutoHide extends StatefulWidget {
+  final Widget child;
+  final ScrollController controller;
+  final AxisDirection direction;
+
+  const AutoHide({
+    super.key,
+    required this.child,
+    required this.controller,
+    required this.direction,
+  });
+
+  @override
+  State<AutoHide> createState() => _AutoHideState();
+}
+
+final class _AutoHideState extends State<AutoHide> {
+  bool _visible = true;
+  bool _isScrolling = false;
+  Timer? _timer;
+
+  @override
+  void initState() {
+    super.initState();
+    widget.controller.addListener(_scrollListener);
+    _setupTimer();
+  }
+
+  @override
+  void dispose() {
+    widget.controller.removeListener(_scrollListener);
+    _timer?.cancel();
+    _timer = null;
+    super.dispose();
+  }
+
+  void _setupTimer() {
+    _timer?.cancel();
+    _timer = Timer.periodic(const Duration(seconds: 3), (_) {
+      debugPrint('[AutoHideFab._timer] trigger timer');
+      if (_isScrolling) return;
+      if (!_visible) return;
+      if (!widget.controller.positions.any((e) => e.maxScrollExtent >= 0)) {
+        return;
+      }
+      setState(() {
+        _visible = false;
+      });
+      _timer?.cancel();
+      _timer = null;
+    });
+  }
+
+  void _scrollListener() {
+    if (_isScrolling) return;
+    _isScrolling = true;
+
+    if (!_visible) {
+      setState(() {
+        _visible = true;
+      });
+      _setupTimer();
+    }
+
+    _isScrolling = false;
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return AnimatedContainer(
+      duration: Durations.medium1,
+      curve: Curves.easeInOutCubic,
+      transform: _transform,
+      child: widget.child,
+    );
+  }
+
+  Matrix4? get _transform {
+    switch (widget.direction) {
+      case AxisDirection.down:
+        return _visible
+            ? Matrix4.identity()
+            : Matrix4.translationValues(0, 55, 0);
+      case AxisDirection.up:
+        return _visible
+            ? Matrix4.identity()
+            : Matrix4.translationValues(0, -55, 0);
+      case AxisDirection.left:
+        return _visible
+            ? Matrix4.identity()
+            : Matrix4.translationValues(-55, 0, 0);
+      case AxisDirection.right:
+        return _visible
+            ? Matrix4.identity()
+            : Matrix4.translationValues(55, 0, 0);
+    }
+  }
+}