hover_issue.dart

import 'package:flutter/material.dart';
import 'package:flutter/rendering.dart';

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

class App extends StatelessWidget {
  const App({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
  return 
    Container(
      color: Colors.white,
      padding: const EdgeInsets.all(15),
      child: const Center(
        child: SizedBox(
          width: 150,
          height: 150,
          child: TestObject(color: Colors.blue),
        ),
      ),
    );
  }
}

class TestObject extends LeafRenderObjectWidget {
  final Color color;

  const TestObject({
    Key? key,
    required this.color,
  }) : super(key: key);

  @override
  RenderObject createRenderObject(BuildContext context) {
    return _RenderTestObject(color: color);
  }

  @override
  void updateRenderObject(BuildContext context, _RenderTestObject renderObject) {
    renderObject.color = color;
  }
}

class _RenderTestObject extends RenderBox {
  Color _color;

  _RenderTestObject({
    required Color color,
  }) : _color = color;

  Color get color => _color;
  set color(Color color) {
    _color = color;

    markNeedsPaint();
  }

  @override
  void handleEvent(PointerEvent event, BoxHitTestEntry entry) {
    assert(debugHandleEvent(event, entry));
    
    print(event);
  }

  @override
  void performLayout() {
    size = computeDryLayout(constraints);
  }

  @override
  bool hitTestSelf(Offset position) => true;

  @override
  Size computeDryLayout(BoxConstraints constraints) {
    final _size = Size(
      constraints.maxWidth,
      constraints.maxHeight,
    );
    
    return constraints.constrain(_size);
  }

  @override
  void paint(PaintingContext context, Offset offset) {
    final canvas = context.canvas;
    
    canvas.translate(offset.dx, offset.dy);

    canvas.save();

    canvas.drawRRect(
      RRect.fromRectAndRadius(
        Rect.fromLTWH(
          0,
          0,
          constraints.maxWidth,
          constraints.maxHeight,
        ),
        Radius.circular(
          constraints.maxHeight * .3,
        ),
      ),
      Paint()..color = color.withOpacity(.3),
    );

    canvas.drawCircle(
      Offset(
        constraints.maxWidth / 2,
        constraints.maxHeight / 2,
      ),
      constraints.maxHeight / 3,
      Paint()..color = color,
    );

    canvas.restore();
  }
}