opt trending header

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

lib/common/widgets/sliver/trending_header.dart

@@ -0,0 +1,55 @@
+import 'package:flutter/foundation.dart' show clampDouble;
+import 'package:flutter/material.dart';
+import 'package:flutter/rendering.dart' show RenderSliverToBoxAdapter;
+
+class TrendingHeader extends SliverToBoxAdapter {
+  const TrendingHeader({
+    super.key,
+    required this.offset,
+    required this.onScrollRatioChanged,
+    required super.child,
+  });
+
+  final double offset;
+  final ValueChanged<double> onScrollRatioChanged;
+
+  @override
+  RenderSliverToBoxAdapter createRenderObject(BuildContext context) {
+    return RenderTrendingHeader(
+      offset: offset,
+      onScrollRatioChanged: onScrollRatioChanged,
+    );
+  }
+
+  @override
+  void updateRenderObject(
+    BuildContext context,
+    RenderTrendingHeader renderObject,
+  ) {
+    renderObject.offset = offset;
+  }
+}
+
+class RenderTrendingHeader extends RenderSliverToBoxAdapter {
+  RenderTrendingHeader({
+    required this.offset,
+    required this.onScrollRatioChanged,
+  });
+
+  double offset;
+  double? _scrollRatio;
+  final ValueChanged<double> onScrollRatioChanged;
+
+  @override
+  void performLayout() {
+    super.performLayout();
+    final scrollOffset = constraints.scrollOffset;
+    final scrollRatio = clampDouble(scrollOffset / offset, 0.0, 1.0);
+    if (_scrollRatio != scrollRatio) {
+      _scrollRatio = scrollRatio;
+      WidgetsBinding.instance.addPostFrameCallback((_) {
+        onScrollRatioChanged(scrollRatio);
+      });
+    }
+  }
+}