Temat: [C#][Windows8] WriteableBitmap - słaba jakość

public async Task SaveWriteableBitmap(WriteableBitmap WB, GfxFileFormat fileFormat, string fileName)
        {
            string FileName = string.Format("{0}.", fileName);
            Guid BitmapEncoderGuid = BitmapEncoder.JpegEncoderId;
            switch (fileFormat)
            {
                case GfxFileFormat.Jpeg:
                    FileName += "jpeg";
                    BitmapEncoderGuid = BitmapEncoder.JpegEncoderId;
                    break;

                case GfxFileFormat.Png:
                    FileName += "png";
                    BitmapEncoderGuid = BitmapEncoder.PngEncoderId;
                    break;

                case GfxFileFormat.Bmp:
                    FileName += "bmp";
                    BitmapEncoderGuid = BitmapEncoder.BmpEncoderId;
                    break;

                case GfxFileFormat.Tiff:
                    FileName += "tiff";
                    BitmapEncoderGuid = BitmapEncoder.TiffEncoderId;
                    break;

                case GfxFileFormat.Gif:
                    FileName += "gif";
                    BitmapEncoderGuid = BitmapEncoder.GifEncoderId;
                    break;
            }

            var file = await KnownFolders.DocumentsLibrary.CreateFileAsync(FileName, CreationCollisionOption.ReplaceExisting);
            using (IRandomAccessStream stream = await file.OpenAsync(FileAccessMode.ReadWrite))
            {
                BitmapEncoder encoder = await BitmapEncoder.CreateAsync(BitmapEncoderGuid, stream);
                Stream pixelStream = WB.PixelBuffer.AsStream();
                byte[] pixels = new byte[pixelStream.Length];
                await pixelStream.ReadAsync(pixels, 0, pixels.Length);

                encoder.SetPixelData(BitmapPixelFormat.Bgra8, 
                                    BitmapAlphaMode.Premultiplied,
                                    (uint)WB.PixelWidth,
                                    (uint)WB.PixelHeight,
                                    96.0,
                                    96.0,
                                    pixels);
                await encoder.FlushAsync();
            }          
        }