Second attempt to demonstrate issue with caching FrameData in TextFrame in Impeller

main.dart

import 'dart:math';
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(
      title: 'Flutter Demo',
      theme: ThemeData(
        colorScheme: .fromSeed(seedColor: Colors.deepPurple),
      ),
      home: const MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

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

  final String title;

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

class _MyHomePageState extends State<MyHomePage> {
  bool reuseDisplayList = true;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        backgroundColor: Theme.of(context).colorScheme.inversePrimary,
        title: Text(widget.title),
      ),
      body: Center(
        child: CustomPaint(
          painter: _MyPainter(reuseDisplayList: reuseDisplayList),
          size: Size(600, 400),
        ),
      ),
      bottomNavigationBar: BottomAppBar(
        child: Row(
          mainAxisAlignment: .center,
          children: [
            Text('Reuse DL: '),
            Checkbox(value: reuseDisplayList, onChanged: (value) {
              setState(() {
                reuseDisplayList = value!;
              });
            },)
          ],
        ),
      ),
    );
  }
}

class _MyPainter extends CustomPainter {
  static final Random random = Random();
  static final staticPicture = makePicture();

  static Picture makePicture() {
    PictureRecorder recorder = PictureRecorder();
    Canvas canvas = Canvas(recorder, Rect.fromLTRB(0, 0, 40, 40));
    canvas.drawRect(
      Rect.fromLTRB(5, 5, 35, 35),
      Paint()
        ..color = Colors.blue
        ..strokeWidth = 2
        ..style = .stroke,
    );
    TextSpan span = TextSpan(
      text: 'Hi',
      style: TextStyle(color: Colors.purple),
    );
    TextPainter painter = TextPainter(
      text: span,
      textDirection: .ltr,
      textAlign: .center
    );
    painter.layout();
    Offset offset = Offset(
        (40 - painter.width) * 0.5,
        (40 - painter.height) * 0.5);
    painter.paint(canvas, offset);
    return recorder.endRecording();
  }

  _MyPainter({required this.reuseDisplayList});
  final bool reuseDisplayList;

  @override
  void paint(Canvas canvas, Size size) {
    for (int x = 0; x < size.width; x += 40) {
      for (int y = 0; y < size.height; y += 40) {
        canvas.save();
        double zoom = random.nextDouble() * 0.75 + 0.5;
        canvas.translate(x + 20, y + 20);
        canvas.scale(zoom, zoom);
        canvas.translate(-20, -20);
        canvas.drawPicture(reuseDisplayList ? staticPicture : makePicture());
        canvas.restore();
      }
    }
  }

  @override
  bool shouldRepaint(covariant CustomPainter oldDelegate) => true;
}