half circle meter (various directional semi-circular gauge using the Flutter radial gauge)

https://support.syncfusion.com/kb/article/10029/how-to-create-the-various-directional-semi-circular-gauge-using-the-flutter-radial-gauge

https://pub.dev/packages/syncfusion_flutter_gauges

 Center(

    child: SfRadialGauge(
      axes: <RadialAxis>[
        RadialAxis(
          axisLineStyle: const AxisLineStyle(thickness: 30,
              color: Colors.grey,
              cornerStyle: CornerStyle.bothCurve
          ),

          startAngle: 180,
            canScaleToFit: false,
            isInversed: false,
            showLabels: false,
            endAngle: 180+180*1,
          showTicks: false,
            pointers: const <GaugePointer>[RangePointer(
              cornerStyle: CornerStyle.bothCurve,
              value: 40, width: 0.1, sizeUnit: GaugeSizeUnit.factor,
              gradient: SweepGradient(
                  colors: <Color>[Color(0xFFFF0000), Color(0xFFF4BE0B)],
                  stops: <double>[0.25, 0.75]
              ),
            )]
            )
      ],
    ))