draw.dart

Container(
  height: 2*50,         //100
  width : sqrt(3)* 50,  //86.602
  child: CustomPaint(
    painter: HexagonPainter(),
    child; Container(),
  ),
),


class HexagonPainter extends CustomPainter {
  @override
  void paint(Canvas canvas, Size size) {
    
  // We'll draw here
    final paint = Paint();
    paint.color = Colors.teal;
    paint.style = PaintingStyle.fill;

    final path = Path();
    path.moveTo(size.width * 0.5, size.height * 0);
    path.lineTo(size.width * 1, size.height * 1 / 4);
    path.lineTo(size.width * 1, size.height * 3 / 4);
    path.lineTo(size.width * 0.5, size.height * 1);
    path.lineTo(size.width * 0, size.height * 3 / 4);
    path.lineTo(size.width * 0, size.height * 1 / 4);
    path.close();

    canvas.drawPath(path, paint);
   
  }

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