repro: BackdropFilter+AnimatedScale (flutter/flutter#164235)

main.dart

import 'dart:ui';

import 'package:flutter/material.dart';

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

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

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      home: Scaffold(
        body: Stack(
          children: [
            Positioned.fill(child: Placeholder()),
            TapResponse(
              child: Stack(children: [FrostedSurface(), Text("Hello World")]),
            ),
          ],
        ),
      ),
    );
  }
}

class TapResponse extends StatefulWidget {
  final Widget child;

  const TapResponse({super.key, required this.child});

  @override
  State<TapResponse> createState() => _TapResponseState();
}

class _TapResponseState extends State<TapResponse> {
  // Current scale factor for the animation.
  double _scale = 1.0;

  void _handlePointerDown(PointerDownEvent event) {
    setState(() => _scale = 0.98);
  }

  void _handlePointerUp(PointerUpEvent event) {
    setState(() => _scale = 1.0);
  }

  void _handlePointerCancel(PointerCancelEvent event) {
    setState(() => _scale = 1.0);
  }

  @override
  Widget build(BuildContext context) {
    return Listener(
      behavior: HitTestBehavior.translucent,
      onPointerDown: _handlePointerDown,
      onPointerUp: _handlePointerUp,
      onPointerCancel: _handlePointerCancel,
      child: AnimatedScale(
        scale: _scale,
        duration: Duration(milliseconds: 300),
        filterQuality: FilterQuality.high,
        child: widget.child,
      ),
    );
  }
}

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

  @override
  Widget build(BuildContext context) {
    return BackdropFilter(
      filter: ImageFilter.blur(sigmaX: 5, sigmaY: 5),
      child: Container(),
    );
  }
}