an interface is
   given in rop.c to the simple Pix image data structure.

2. Binary morphology

   This is a source for efficient implementations of binary morphology
   Details are found starting at the Leptonica home page, and by reading
   the source code.

   Binary morphology is implemented two ways:

     (a) Successive full image rasterops for arbitrary
         structuring elements (Sels)

     (b) Destination word accumulation (dwa) for specific Sels.
         This code is automatically generated.