out Leptonica to hold the packed data is a Pix,
   which is defined and documented in pix.h.  The alpha component
   in RGB images is significantly better supported, starting in 1.70.

   Additionally, a FPix is provided for handling 2D arrays of floats,
   and a DPix is provided for 2D arrays of doubles.  Converters
   between these and the Pix are given.

8. Conversion between Pix and other in-memory raster formats

 . If you use Leptonica with other imaging libraries, you will need
   functions to conver