This is simple raster graphics package. It's basically a redesigned and reimplemented edition of Sun's old pixrect library. It does rectangle operations (bit-blits), points, lines, text (using vfont files), stencils, tiling, image file i/o (using Sun rasterfiles), etc.
There is also a subsidiary library that provides an API very similar to pixrect. You can use this to keep your pixrect-based programs going under Solaris 2.x, where Sun has decided to get rid of pixrect.
All system-dependent sections are in the file raster_sys.c, marked with the string "SYS". The main system-dependent part is getting the address of the frame buffer. It assumes a frame buffer either one bit or eight bits deep, that can be byte-addressed but prefers to be longword-addressed. Currently it has been implemented on Suns, and it should work on most combinations of Sun frame buffers and operating systems. If you port to a non-Sun system let me know, I'm very interested! It should be fairly straightforward.