The SDL_gfx library evolved out of the SDL_gfxPrimitives code which provided
basic drawing routines such as lines, circles or polygons and SDL_rotozoom
which implemented a interpolating rotozoomer for SDL surfaces.

The current components of the SDL_gfx library are:

   - Graphic Primitives (SDL_gfxPrimitves.h)
   - Rotozoomer (SDL_rotozoom.h)
   - Framerate control (SDL_framerate.h)
   - MMX image filters (SDL_imageFilter.h)

WWW: http://www.ferzkopp.net/Software/SDL_gfx-2.0/