main.dart

class ExpensivePainter extends CustomPainter {
  @override
  void paint(Canvas canvas, Size size) {
    final double boxWidth = size.width / 50;
    final double boxHeight = size.height / 50;
    for (int i = 0; i < 50; i++) {
      for (int j = 0; j < 50; j++) {
        final Rect rect = Rect.fromLTWH(i * boxWidth, j * boxHeight, boxWidth, boxHeight);
        canvas.drawRect(rect, Paint()
          ..style = PaintingStyle.fill
          ..color = Colors.red
        );
      }
    }
  }

  @override
  bool shouldRepaint(covariant CustomPainter oldDelegate) {
    return false;
  }
}