Colormaps, etc.

Steve Lamont (
Sat, 30 Nov 96 13:28:14 PST

To subscribers of the xforms list from (Steve Lamont) :

Dikoma C. Shungu sez:
> If you have an 8-bit display and the *total* number of entries in all the
> colormap "segments" being requested by all the applications on your desktop
> exceeds 256 at any given time, your window manager will give priority to the
> window under the system cursor, and deallocate other windows' colors
> (as necessary.) ...

DCS's response is more or less correct here but I'd like to interject
one small emendation.

The window manager does not manage colormaps -- the X server does.
They are two separate programs. The window manager operates in a
privileged state with respect to the server.

The server will reparent any top level windows to the window manager,
and the window manager is responsible for any decoration (title bars,
borders, and so forth) but it is the server which actually pushes the
pixels at the display. The server and the window manager don't even
have to be running on the same machine.

> ... This does not happen on my new Sun Ultra-II which
> has a 24-bit display.

Show off. :-)

> IMHO, working with colors under X is a royal pain!

No more than working with any color mapped device. Color quantization
is a real pain in the tush, though. BTW, I've finally written a
little quantization library based upon the octree algorithm given in
_Graphics Gems_ (GG I) that may be of general use. If there's enough
interest, I'll try to write up some manual pages and installation
instructions and make it available (GNU Copyleft) on my anonymous FTP

To unsubscribe, send the message "unsubscribe" to or see