Create a StatelessWidget say MyArc which accepts a diameter.
class MyArc extends StatelessWidget {
final double diameter;
const MyArc({Key key, this.diameter = 200}) : super(key: key);
@override
Widget build(BuildContext context) {
return CustomPaint(
painter: MyPainter(),
size: Size(diameter, diameter),
);
}
}
// This is the Painter class
class MyPainter extends CustomPainter {
@override
void paint(Canvas canvas, Size size) {
Paint paint = Paint()..color = Colors.blue;
canvas.drawArc(
Rect.fromCenter(
center: Offset(size.height / 2, size.width / 2),
height: size.height,
width: size.width,
),
math.pi,
math.pi,
false,
paint,
);
}
@override
bool shouldRepaint(CustomPainter oldDelegate) => false;
}
Usage:
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(),
body: MyArc(diameter: 300),
);
}
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