there is currently no SDL backend available for painting or UI, but
it's possible to map SDL_Surface to Fog::Image and to paint into it.
There is an outdated example I improved today which can be used as a
skeleton:
http://fog-framework.blogspot.com/2010/04/using-fog-in-within-sdl.html
I'm not sure whether it will work, because Fog was heavily
refactorized, but the concepts are the same, and method names should
match the trunk version. The painting is done by Fog-Framework, there
is no work SDL can do, because the target of Fog and SDL libraries is
very different.
Feel free to ask questions if you get into troubles;)
Best regards
Petr Kobalicek