opt video header

Signed-off-by: dom <githubaccount56556@proton.me>

lib/common/widgets/sliver/video_header.dart

@@ -0,0 +1,59 @@
+import 'package:PiliPlus/common/widgets/sliver/sliver_pinned_dynamic_header.dart';
+import 'package:PiliPlus/utils/extension/num_ext.dart';
+import 'package:flutter/foundation.dart' show clampDouble;
+import 'package:flutter/material.dart';
+
+class VideoHeader extends SliverPinnedDynamicHeader {
+  const VideoHeader({
+    super.key,
+    required super.minExtent,
+    required super.maxExtent,
+    required this.minVideoHeight,
+    required this.onScrollRatioChanged,
+    required super.child,
+  });
+
+  final double minVideoHeight;
+  final ValueChanged<double> onScrollRatioChanged;
+
+  @override
+  RenderObject createRenderObject(BuildContext context) {
+    return RenderVideoHeader(
+      minExtent: minExtent,
+      maxExtent: maxExtent,
+      minVideoHeight: minVideoHeight,
+      onScrollRatioChanged: onScrollRatioChanged,
+    );
+  }
+}
+
+class RenderVideoHeader extends RenderSliverPinnedDynamicHeader {
+  RenderVideoHeader({
+    required super.minExtent,
+    required super.maxExtent,
+    required this.minVideoHeight,
+    required this.onScrollRatioChanged,
+  });
+
+  double? _scrollRatio;
+  final double minVideoHeight;
+  final ValueChanged<double> onScrollRatioChanged;
+
+  @override
+  void performLayout() {
+    super.performLayout();
+    final scrollOffset = constraints.scrollOffset;
+    final offset = scrollOffset - (maxExtent - minVideoHeight);
+    final scrollRatio = clampDouble(
+      offset.toPrecision(2) / (minVideoHeight - kToolbarHeight).toPrecision(2),
+      0.0,
+      1.0,
+    );
+    if (_scrollRatio != scrollRatio) {
+      _scrollRatio = scrollRatio;
+      WidgetsBinding.instance.addPostFrameCallback((_) {
+        onScrollRatioChanged(scrollRatio);
+      });
+    }
+  }
+}