WriteableBitmap without antialiasing

Question

Im using the http://writeablebitmapex.codeplex.com/ WPF dll. For drawing objects on a writeablebitmap. Now I dont want to have antialised pixels.

for example I draw a circle

using (writeableBmp.GetBitmapContext())
                {
                    writeableBmp.FillEllipse((int)origin.X, (int)origin.Y, (int)(origin.X + ell.Width), (int)(origin.Y + ell.Height), Colors.Blue);

                }
               img.Source = writeableBmp.Resize(68, 42, WriteableBitmapExtensions.Interpolation.NearestNeighbor);

I want to have sharp edges.

Why do I need that? I have LED strips with a resolution of 68 x 42 and I write a WPF application to control them. any idea i can manage that?

UPDATE: the solution of my problem is quite simple just set the RenderOptions

RenderOptions.SetBitmapScalingMode(i, BitmapScalingMode.NearestNeighbor); RenderOptions.SetEdgeMode(i, EdgeMode.Aliased