How to save strokes drawn on the canvas as an image file

The following class can be used to render an InkDocument to a raster image:

static class InkDocumentRenderer
{
        public static async Task<WriteableBitmap> RenderToBitmapAsync(InkDocument inkDocument, Color backgroundColor)  
        {  
               PixelData pixelData = Render(inkDocument, backgroundColor);  

               WriteableBitmap wb = new WriteableBitmap((int)pixelData.PixelWidth, (int)pixelData.PixelHeight);  

               using (Stream stream = wb.PixelBuffer.AsStream())  
               {
                       byte[] sourcePixels = pixelData.Data.ToArray();  
                       await stream.WriteAsync(sourcePixels, 0, sourcePixels.Length);  
               }

               return wb;
        }

        public static PixelData Render(InkDocument inkDocument, Color backgroundColor)
        {
               const float scale = 1.0f;
               Size size = new Size(inkDocument.Bounds.Width, inkDocument.Bounds.Height);
               Rect rectPx;

               using (Graphics graphics = new Graphics())
               using (RenderingContext rc = graphics.GetRenderingContext())
               using (Layer targetLayer = graphics.CreateLayer(size, scale))
               {
                       rc.SetTarget(targetLayer);
                       rc.ClearColor(backgroundColor);

                       using (StrokeRenderer strokeRenderer = new StrokeRenderer())
                       {
                               strokeRenderer.Brush = new SolidColorBrush();
                               strokeRenderer.StrokeWidth = null;
                               strokeRenderer.UseVariableAlpha = false;
                               strokeRenderer.Ts = 0.0f;
                               strokeRenderer.Tf = 1.0f;
                               strokeRenderer.Init(graphics, size, scale);

                               RenderAllStrokesToLayer(strokeRenderer, inkDocument, targetLayer);
                       }

                      rc.SetTarget(targetLayer)
                       PixelData pixelData = rc.ReadPixels(out rectPx);
                       return pixelData;
               }
        }

        public static void RenderAllStrokesToLayer(StrokeRenderer strokeRenderer, InkDocument inkDocument, Layer target)
        {
               var recursiveEnumerator = inkDocument.Root.GetEnumerator();

               while (recursiveEnumerator.MoveNext())
               {
                       if (recursiveEnumerator.Current is InkStroke s)
                       {
                               strokeRenderer.Color = s.Color;
                               strokeRenderer.Ts = s.Ts;
                               strokeRenderer.Tf = s.Tf;

                               // draw the stroke in the strokes layer
                               strokeRenderer.ResetAndClear();
                               strokeRenderer.DrawStroke(s.Path, 0, s.Path.PointsCount, true);
                               strokeRenderer.BlendStrokeInLayer(target, BlendMode.Normal);
                       }
               }
        }
}