glitchy_text.dart

import 'package:flutter/material.dart';

final Color darkBlue = Color.fromARGB(255, 18, 32, 47);

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      theme: ThemeData.dark().copyWith(scaffoldBackgroundColor: darkBlue),
      debugShowCheckedModeBanner: false,
      home: Scaffold(
        body: Center(
          child: MyWidget(),
        ),
      ),
    );
  }
}

class MyWidget extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return CustomPaint(
      painter: MyPainter(),
      child: SizedBox(width: 400, height: 200),
    );
  }
}

class MyPainter extends CustomPainter {
  void paint(canvas, size) {
    final span = TextSpan(style: TextStyle(color: Colors.white, fontSize: 80, fontWeight: FontWeight.bold), text: "Glitchy");
    final tp = TextPainter(text: span, textAlign: TextAlign.center, textDirection: TextDirection.ltr);
    tp.layout(minWidth: size.width);
    
    final glitchPath = Path()..addRect(
      Rect.fromLTWH(0, 40, size.width, 20),
    );

    final nonGlitchPath = Path.combine(
      PathOperation.difference,
      Path()..addRect(
        Rect.fromLTWH(0, 0, size.width, size.height),
      ),
      glitchPath,
    );
    
    canvas.save();
    canvas.translate(
      0, size.height / 2 - tp.height / 2,
    );
    
    canvas.save();
    canvas.clipPath(glitchPath);
    tp.paint(canvas, Offset(-5, 0));
    canvas.restore();
    
    canvas.save();
    canvas.clipPath(nonGlitchPath);
    tp.paint(canvas, Offset.zero);
    canvas.restore();
    
    canvas.restore();
  }
  
  bool shouldRepaint(_) => false;
}