private void readCmykMemoryBitmap() {
   Debug.Assert(this.image.wpfImage.Format == PixelFormats.Cmyk32,"Only CMYK support");
   int _nOfChannels = 4;

   int height = this.image.PixelHeight;
   int width = this.image.PixelWidth;

   byte[] _destImageData = new byte[_nOfChannels * width * height];

   int _stride = _nOfChannels * width;
   this.image.wpfImage.CopyPixels(_destImageData,_stride,0);

   FlateDecode fd = new FlateDecode();

   byte[] imageDataCompressed = fd.Encode(_destImageData);

   Stream = new PdfStream(imageDataCompressed,this);
   Elements[Keys.Length] = new PdfInteger(imageDataCompressed.Length);
   Elements[Keys.Filter] = new PdfName("/FlateDecode");
   Elements[Keys.Width] = new PdfInteger(width);
   Elements[Keys.Height] = new PdfInteger(height);
   Elements[Keys.BitsPerComponent] = new PdfInteger(8);
   Elements[Keys.ColorSpace] = new PdfName("/DeviceCMYK");
   if(image.Interpolate)
      Elements[Keys.Interpolate] = PdfBoolean.True;
}