FrameCoord() {}
      FrameCoord(unsigned short x, unsigned short y) : column(x), row(y) {}

      uint16_t column;
      uint16_t row;

      enum { Version=1 };

      FrameFccdConfigV1();
      FrameFccdConfigV1(const FrameFccdConfigV1&);
      //  size of this structure
      unsigned  size()        const         { return sizeof(*this); }

      enum { Version=1 };
      enum Forwarding { NoFrame, FullFrame, RegionOfInterest };
      enum Processing { NoProcessing, GssFullFrame, GssRegionOfInterest, GssThreshold };

     FrameFexConfigV1();
      FrameFexConfigV1( Forwarding        forwarding,
                        unsigned          fwd_prescale,
                        Processing        processing,
                        const FrameCoord& roiBegin,
                        const FrameCoord& roiEnd,
                        unsigned          threshold,
                        unsigned          masked_pixels,
                        const FrameCoord* masked_coords );

      FrameFexConfigV1(const FrameFexConfigV1&);

      //  forwarding policy for frame data
      Forwarding        forwarding() const;

      //  prescale of events with forwarded frames
      unsigned          forward_prescale() const;

      //  algorithm to apply to frames to produce processed output
      Processing        processing() const;

      //  coordinate of start of rectangular region of interest (inclusive)
      const FrameCoord& roiBegin  () const;

      //  coordinate of finish of rectangular region of interest (exclusive)
      const FrameCoord& roiEnd    () const;

      //  pixel data threshold value to apply in processing
      unsigned          threshold () const;

      //  count of masked pixels to exclude from processing
      unsigned          number_of_masked_pixels () const;

      //  location of masked pixel coordinates
      //  appended to the end of this structure
      const FrameCoord& masked_pixel_coordinates() const;

      //  size of this structure
      //  (including appended masked pixel coordinates)
      unsigned size() const;

      enum {Version=1};

      FrameV1() {}
      //  FrameV1 with unassigned contents
      FrameV1(unsigned width, unsigned height, unsigned depth, unsigned offset);
      //  Copy constructor
      FrameV1(const FrameV1&);
    public:
      //  number of pixels in a row
      unsigned width () const;
      //  number of pixels in a column
      unsigned height() const;
      //  number of bits per pixel
      unsigned depth () const;
      //  fixed offset/pedestal value of pixel data
      unsigned offset() const;

      // number of bytes per pixel
      unsigned depth_bytes() const;
      // size of pixel data appended to the end of this structure
      unsigned data_size  () const;

      //  beginning of pixel data
      const unsigned char* data() const;
      //  location of individual pixel datum
      const unsigned char* pixel(unsigned x,unsigned y) const;

      enum { Version=1 };

      TwoDGaussianV1();
      TwoDGaussianV1(uint64_t n,
                     double xmean,
                     double ymean,
                     double major_ax_width,
                     double minor_ax_width,
                     double tilt);
      ~TwoDGaussianV1();

      uint64_t integral() const;
      double xmean() const;
      double ymean() const;
      double major_axis_width() const;
      double minor_axis_width() const;
      double major_axis_tilt () const;