refa persistent header & dynamic sliver appbar

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

lib/common/widgets/sliver/sliver_pinned_dynamic_header.dart

@@ -0,0 +1,123 @@
+/*
+ * This file is part of PiliPlus
+ *
+ * PiliPlus is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * PiliPlus is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with PiliPlus.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+import 'dart:math' as math;
+
+import 'package:flutter/foundation.dart' show clampDouble;
+import 'package:flutter/rendering.dart'
+    show RenderSliverSingleBoxAdapter, SliverConstraints, SliverGeometry;
+import 'package:flutter/widgets.dart';
+
+/// ref [SliverPersistentHeader]
+class SliverPinnedDynamicHeader extends SingleChildRenderObjectWidget {
+  const SliverPinnedDynamicHeader({
+    super.key,
+    required Widget super.child,
+    required this.minExtent,
+    required this.maxExtent,
+  });
+
+  final double minExtent;
+  final double maxExtent;
+
+  @override
+  RenderObject createRenderObject(BuildContext context) {
+    return RenderSliverPinnedDynamicHeader(
+      minExtent: minExtent,
+      maxExtent: maxExtent,
+    );
+  }
+
+  @override
+  void updateRenderObject(
+    BuildContext context,
+    RenderSliverPinnedDynamicHeader renderObject,
+  ) {
+    renderObject
+      ..minExtent = minExtent
+      ..maxExtent = maxExtent;
+  }
+}
+
+class RenderSliverPinnedDynamicHeader extends RenderSliverSingleBoxAdapter {
+  RenderSliverPinnedDynamicHeader({
+    required double minExtent,
+    required double maxExtent,
+  }) : _minExtent = minExtent,
+       _maxExtent = maxExtent;
+
+  double _minExtent;
+  double get minExtent => _minExtent;
+  set minExtent(double value) {
+    if (_minExtent == value) return;
+    _minExtent = value;
+    markNeedsLayout();
+  }
+
+  double _maxExtent;
+  double get maxExtent => _maxExtent;
+  set maxExtent(double value) {
+    // removed
+    // if (_maxExtent == value) return;
+    _maxExtent = value;
+    markNeedsLayout();
+  }
+
+  @override
+  void performLayout() {
+    final SliverConstraints constraints = this.constraints;
+    final double shrinkOffset = math.min(constraints.scrollOffset, maxExtent);
+    child!.layout(
+      constraints.asBoxConstraints(
+        maxExtent: math.max(minExtent, maxExtent - shrinkOffset),
+      ),
+      parentUsesSize: true,
+    );
+    final double childExtent = child!.size.height;
+    final double effectiveRemainingPaintExtent = math.max(
+      0,
+      constraints.remainingPaintExtent - constraints.overlap,
+    );
+    final double layoutExtent = clampDouble(
+      maxExtent - constraints.scrollOffset,
+      0.0,
+      effectiveRemainingPaintExtent,
+    );
+    geometry = SliverGeometry(
+      scrollExtent: maxExtent,
+      paintOrigin: constraints.overlap,
+      paintExtent: math.min(childExtent, effectiveRemainingPaintExtent),
+      layoutExtent: layoutExtent,
+      maxPaintExtent: maxExtent,
+      maxScrollObstructionExtent: minExtent,
+      cacheExtent: layoutExtent > 0.0
+          ? -constraints.cacheOrigin + layoutExtent
+          : layoutExtent,
+      hasVisualOverflow: false,
+    );
+  }
+
+  @override
+  void paint(PaintingContext context, Offset offset) {
+    if (child != null && geometry!.visible) {
+      context.paintChild(child!, offset);
+    }
+  }
+
+  @override
+  double childMainAxisPosition(RenderBox child) => 0.0;
+}