SliverVisibiltyDetector should consider SliverConstraints overlap

[LaysDragon]

Problem description

visibility_detector
version: 0.4.0+2
SliverVisibiltyDetector should consider SliverConstraints overlap data to made its more reliable within sliver scroll view.

Steps to reproduce

https://zapp.run/edit/flutter-zj80065pj810

Code

import 'dart:async';

import 'package:flutter/material.dart';
import 'package:flutter/src/rendering/sliver.dart';
import 'package:visibility_detector/visibility_detector.dart';

void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter App!!',
      home: const MyHomePage(title: 'Flutter Example App'),
      debugShowCheckedModeBanner: false,
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({super.key, required this.title});

  final String title;

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  VisibilityInfo? info;
  SliverConstraints? constraints;

  @override
  Widget build(BuildContext context) {
    return Material(
      child: CustomScrollView(
        // shrinkWrap: true,
        physics: BouncingScrollPhysics(),
        slivers: [
          SliverPersistentHeader(
            delegate: DemoHeaderDelegate(info: info, constraints: constraints),
            pinned: true,
          ),
          SliverLayoutBuilder(
            builder: (BuildContext, constraints) {
              scheduleMicrotask(() {
                setState(() {
                  this.constraints = constraints;
                });
              });

              return SliverVisibilityDetector(
                key: ValueKey('content'),
                onVisibilityChanged: (VisibilityInfo info) {
                  setState(() {
                    this.info = info;
                  });
                },
                sliver: SliverToBoxAdapter(
                  child: Container(
                    height: 200,
                    color: Colors.grey,
                    child: Text('content'),
                  ),
                ),
              );
            },
          ),
          SliverToBoxAdapter(
            child: SizedBox(
              height: 2000,
              child: Text('other things blablabla'),
            ),
          )
        ],
      ),
    );
  }
}

class DemoHeaderDelegate extends SliverPersistentHeaderDelegate {
  VisibilityInfo? info;
  SliverConstraints? constraints;
  DemoHeaderDelegate({this.info, this.constraints});

  @override
  Widget build(
      BuildContext context, double shrinkOffset, bool overlapsContent) {
    return Container(
      child: Center(
        child: Column(
          children: [
            Text('[header]'),
            Text(
                'visibleFraction:${info?.visibleFraction.toStringAsFixed(2)} visibleBounds.height:${info?.visibleBounds.height.round()}'),
            Text('SliverConstraints.overlap:${constraints?.overlap.round()}'),
          ],
        ),
      ),
      color: Colors.yellow.withOpacity(0.5),
    );
  }

  @override
  double get maxExtent => 100;

  @override
  double get minExtent => 50;

  @override
  bool shouldRebuild(covariant SliverPersistentHeaderDelegate oldDelegate) {
    return true;
  }
}

Expected behavior

It should able to detected the overlap from other sliver with SliverConstraints.

Actual behavior

Its only detected if a sliver visible within sliver scroll view

Environment

Windows 10
flutter 3.2.0

[LaysDragon]

I currently fix its manually by creating a OverlayRenderVisibilityDetectorBase with patched code in _determineVisibility method of RenderVisibilityDetectorBase

mixin OverlayRenderVisibilityDetectorBase on RenderSliver{
//...skipping some code
//...
  VisibilityInfo _determineVisibility(ContainerLayer? layer, Rect bounds) {
  //...skipping some code
  //...
    var info = VisibilityInfo.fromRects(
      key: key,
      widgetBounds: MatrixUtils.transformRect(transform, bounds),
      clipRect: clip,
    );

    switch (applyGrowthDirectionToAxisDirection(
      constraints.axisDirection,
      constraints.growthDirection,
    )) {
      case AxisDirection.down:
        info = VisibilityInfo(
          key: info.key,
          size: info.size,
          visibleBounds: Rect.fromLTRB(info.visibleBounds.left, info.visibleBounds.top + constraints.overlap,
              info.visibleBounds.right, info.visibleBounds.bottom),
        );
        if (info.visibleBounds.height <= 0) {
          return VisibilityInfo(
            key: key,
            size: info.size,
          );
        }
        break;
      case AxisDirection.up:
        info = VisibilityInfo(
          key: info.key,
          size: info.size,
          visibleBounds: Rect.fromLTRB(info.visibleBounds.left, info.visibleBounds.top, info.visibleBounds.right,
              info.visibleBounds.bottom - constraints.overlap),
        );
        if (info.visibleBounds.height <= 0) {
          return VisibilityInfo(
            key: key,
            size: info.size,
          );
        }
        break;
      case AxisDirection.right:
        info = VisibilityInfo(
          key: info.key,
          size: info.size,
          visibleBounds: Rect.fromLTRB(info.visibleBounds.left + constraints.overlap, info.visibleBounds.top,
              info.visibleBounds.right, info.visibleBounds.bottom),
        );
        if (info.visibleBounds.width <= 0) {
          return VisibilityInfo(
            key: key,
            size: info.size,
          );
        }
        break;
      case AxisDirection.left:
        info = VisibilityInfo(
          key: info.key,
          size: info.size,
          visibleBounds: Rect.fromLTRB(info.visibleBounds.left, info.visibleBounds.top,
              info.visibleBounds.right - constraints.overlap, info.visibleBounds.bottom),
        );
        if (info.visibleBounds.width <= 0) {
          return VisibilityInfo(
            key: key,
            size: info.size,
          );
        }
        break;
    }

    return info;
  }
}