Am trying to make simple wpf viewer and when representing image i used this code 

       public BitmapSource CurrentFrameData(ClearCanvas.ImageViewer.StudyManagement.Frame frm)

        {

            IPresentationImage presentationImage =

                    PresentationImageFactory.Create(frm);

            int width = frm.Columns;

            int height = frm.Rows;

            System.Drawing.Bitmap bmp = presentationImage.DrawToBitmap(width, height);

             BitmapSource output = System.Windows.Interop.Imaging.CreateBitmapSourceFromHBitmap(

              bmp.GetHbitmap(),

              IntPtr.Zero,

              Int32Rect.Empty,

              BitmapSizeOptions.FromWidthAndHeight(width, height));

        return output;

}

and Now i want to change the windows/level so what to do ??