如何在OxyPlot AngleAxis和MagnitudeAxis中画圆？

public class CirclePlotModel : PlotModel
{
    public CirclePlotModel()
    {
        Circle circle = new Circle
        {
            Center = new DataPoint(0, 0),
            Radius = 1,
            LineStyle = LineStyle.Solid,
            LineColor = OxyColors.Blue,
            LineWidth = 2
        };
        Items.Add(circle);
    }
}

public class Circle : ShapeItem
{
    public DataPoint Center { get; set; }
    public double Radius { get; set; }

    public Circle()
    {
        BaseLineWidth = 2;
    }

    protected override void Render(IRenderContext rc)
    {
        double angleStart = 0;
        double angleEnd = 2 * Math.PI;

        double x1 = Center.X + Radius * Math.Cos(angleStart);
        double y1 = Center.Y + Radius * Math.Sin(angleStart);
        double x2 = Center.X + Radius * Math.Cos(angleEnd);
        double y2 = Center.Y + Radius * Math.Sin(angleEnd);

        rc.DrawLineTo(x1, y1, x2, y2, this.BaseLineWidth);

        for (double angle = angleStart; angle <= angleEnd; angle += 0.01)
        {
            double x = Center.X + Radius * Math.Cos(angle);
            double y = Center.Y + Radius * Math.Sin(angle);
            rc.DrawLineTo(x, y, this.BaseLineWidth);
        }
    }
}

public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();

        CirclePlotModel model = new CirclePlotModel();
        oxyPlotView.Model = model;
    }
}