I am looking to create polygons (halos/rings) around the mouse cursor programmatically with C# using the ArcGIS Pro SDK.  I have figured out how to create the halos by using **System.Windows.Forms.Control.MousePosition** and then converting into lat/long by using **MapView.Active.ScreenToMap**.  I have also used a MouseHook from the Win32Api to give me a MouseMove event.  This allows me to associate the polygon to the mouse cursor and move it around the map as an overlay.  

The problem that I am having now is that I can only create a polygon (halo/ring) with a radius in pixels.  I need to be able to use map units, like feet, meters, miles, kilometers, etc.  For example, I want to create a polygon (halo/ring) that has a radius of 100 feet.  

Is there some way to accomplish this?

The following is code that I am using that doesn't work.  It only functions with pixels.

    await QueuedTask.Run(() =>
                    {
                        System.Drawing.Point pt = System.Windows.Forms.Control.MousePosition;
                        MapPoint mapPt = MapView.Active.ScreenToMap(new Point(pt.X, pt.Y));
                        double bufferRadius = 100;

                        ArcGIS.Core.Geometry.Polygon poly = CreateHaloPolygon(mapPt, Convert.ToInt32(bufferRadius), out double haloRadius);
                        //_graphics.Add(new GraphicProperties(null, null, polySymRef, poly, lineColor, bufferRadius, bufferInfo[2]));
                        _graphics.Add(new GraphicProperties(null, null, polySymRef, poly, lineColor, haloRadius, bufferInfo[2]));
                    });

    private ArcGIS.Core.Geometry.Polygon CreateHaloPolygon(MapPoint mapPoint, int pixels, out double radius)
        {
            // Get the halo radius
            Point screenPoint = MapView.Active.MapToScreen(mapPoint);
            Point radiusScreenPoint = new Point((screenPoint.X + pixels), screenPoint.Y);
            MapPoint radiusMapPoint = MapView.Active.ScreenToMap(radiusScreenPoint);
            radius = GeometryEngine.Instance.Distance(mapPoint, radiusMapPoint);

            // Build a circle geometry
            Coordinate2D coord2D = new Coordinate2D(mapPoint);
            EllipticArcSegment arcSegment = EllipticArcBuilder.CreateEllipticArcSegment(coord2D, radius, esriArcOrientation.esriArcClockwise, MapView.Active.Map.SpatialReference);
            PolygonBuilder polyBuilder = new PolygonBuilder(new[] { arcSegment });

            return polyBuilder.ToGeometry();
        }