ClipSamplePainter

ClipSamplePainter.dart

import 'dart:ui';

import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
        title: 'Flutter Demo',
        debugShowCheckedModeBanner: false,
        theme: ThemeData(
          colorScheme: ColorScheme.fromSeed(seedColor: Colors.deepPurple),
          useMaterial3: true,
        ),
        home: const MyHomePage());
  }
}

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

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        backgroundColor: Theme.of(context).colorScheme.inversePrimary,
      ),
      body: Center(
        child: CustomPaint(
          painter: ClipSamplePainter(),
        ),
      ),
    );
  }
}

class ClipSamplePainter extends CustomPainter {
  void paint(Canvas canvas, Size size) {
    canvas.clipRect(
      Rect.fromLTRB(100, 100, size.width - 100, size.height - 100),
//       clipOp: ClipOp.difference,
    );
    canvas.drawRect(Rect.largest, Paint()..color = Colors.black);
  }

  bool shouldRepaint(CustomPainter oldDelegate) => false;
}