How BeveledRectangleBorder for TextField in flutter - flutter

Question

I have TextField i need to change the border Corners Cut, I have try to do with wrap TextField on Container and apply BeveledRectangleBorder but is not proper.
Please suggest me how can do this.

Answer 1

Update
After searching a little i've found the source code of that design you shared with me. They have build a custom input border (CutCornersBorder) for that particular style. You can use that file and add that to your theme to get that look of your TextField without adding any extra code.
CutCornersBorder
return MaterialApp(
home: HomePage(),
theme: ThemeData(
inputDecorationTheme: InputDecorationTheme(border: CutCornersBorder()),
),
);
Full Preview
OLD
You can do it by creating your own custom painter implementation.
FlatCorneredBackgroundPainter
class FlatCorneredBackgroundPainter extends CustomPainter {
double radius, strokeWidth;
Color strokeColor;
FlatCorneredBackgroundPainter(
{this.radius = 10, this.strokeWidth = 4, this.strokeColor = Colors.blue});
#override
void paint(Canvas canvas, Size size) {
double w = size.width;
double h = size.height;
Paint paint = Paint()
..style = PaintingStyle.stroke
..strokeWidth = strokeWidth
..color = strokeColor;
Path path = Path()
..addPolygon([
Offset(radius, 0),
Offset(w - radius, 0),
Offset(w, radius),
Offset(w, h - radius),
Offset(w - radius, h),
Offset(radius, h),
Offset(0, h - radius),
Offset(0, radius),
], true);
canvas.drawPath(path, paint);
}
#override
bool shouldRepaint(CustomPainter oldDelegate) {
return false;
}
}
Usage
class HomePage extends StatelessWidget {
#override
Widget build(BuildContext context) {
return Scaffold(
body: Center(
child: CustomPaint(
painter: FlatCorneredBackgroundPainter(radius: 10.0, strokeColor: Colors.red, strokeWidth: 2),
child: Container(
width: 300,
height: 70,
padding: const EdgeInsets.all(8.0),
child: TextField(),
),
),
),
);
}
}