Desktop infos?

How to get easily in SDL the necessary infos about
the current WM desktop :

current color depth (bpp), refresh rate ?
current width and height of the desktop ?

Then, knowing this, what is the command to
create a window (using the current bpp, width, height, refresh rate) on the desktop, say 600x800, on a
surface 2500x4000. (I need to scroll around, fast) ?

I read the sources and the html, but I get confused,
it seems that these basic infos are not readily available.
(Fullscreen only syndrom ?)


(Plz reply with a cc: to me, as I am currently
unsubscribed from the mailing list)