hearts_painter.dart

class HeartsPainter extends CustomPainter {

  final Paint hearPaint = Paint()
    ..style = PaintingStyle.stroke;

  @override
  void paint(Canvas canvas, Size size) {
    print('Hearts Painting..');
    const int count = 700;
    for (int i = 0; i < count; i++) {
      _drawHeart(
          canvas,
          Size((i + 1) / count * size.width, (i + 1) / count * size.height),
          Colors.blue.withRed((i / count * 255).toInt()).withOpacity(0.4));
    }
  }

  void _drawHeart(Canvas canvas, Size size, Color color) {
    final Path path = Path();
    final double width = size.width;
    final double height = size.height;

    // Starting point
    path.moveTo(width / 2, height / 5);

    // Upper left path
    path.cubicTo(
        5 * width / 14, 0,
        0, height / 15,
        width / 28, 2 * height / 5);

    // Lower left path
    path.cubicTo(
        width / 14, 2 * height / 3,
        3 * width / 7, 5 * height / 6,
        width / 2, height);

    // Lower right path
    path.cubicTo(
        4 * width / 7, 5 * height / 6,
        13 * width / 14, 2 * height / 3,
        27 * width / 28, 2 * height / 5);

    // Upper right path
    path.cubicTo(
        width, height / 15,
        9 * width / 14, 0,
        width / 2, height / 5);

    canvas.drawPath(
        path,
        hearPaint..color = color);
  }

  @override
  bool shouldRepaint(HeartsPainter oldDelegate) => false;
}