24-bit monitor and grass

Mark P. Line markline at henson.cc.wwu.edu
Thu Oct 7 19:49:03 EDT 1993

On Thu, 7 Oct 1993, Darrell McCauley wrote:

> "Mark P. Line" (markline at henson.cc.wwu.edu) writes on 7 Oct 93:
> >I've been following this thread and am becoming confuseder and confuseder.
> >I'm not new to GRASS and not new to X, but I'm new to GRASS with XDRIVER,
> >so maybe I've missed something. But I had the impression that GRASS (and
> >presumably XDRIVER) is coded for *24 bit* color in the first place -- I
> don't get "data" or "display libraries" confused with "display
> capabilities" (is this the case?)

I don't think so, but if it is, I seem to be in good company. One person
posted to this thread saying that "GRASS" requires an 8-bit PseudoColor
visual on the part of the X server you have running -- did he mean data,
display library or display capabilities? Another poster said that there's
no way a 24-bit monitor (the physical beast) could *possibly* run with
GRASS (data? driver? library?) without massive recoding. Another poster
said that he *has* a 24-bit monitor running with GRASS -- that takes care
of the physical side, but is the X server in 8-bit mode or 24-bit, how
many colors are being requested across X11, and what is XDRIVER requesting
in the way of colors?

The reason I said I was confused was because, as nearly as I can put
things from the whole thread together, there's no reason why a 24-bit
monitor can't display 24-bit colors, there's no reason why an X server
cannot handle 24-bit colors on a 24-bit monitor, there's no reason why
XDRIVER couldn't request 24-bit colors over X11, there's no reason why the
GRASS display library can't set 24-bit colors for display by XDRIVER (it
does, in fact, according to my Programmer's manual), and there's no reason
why higher-level routines can't pass 24-bit color table information from
raster layers to the display library. So, to reiterate the question posed
by that poor user who originally ventured out to ask the experts on this
list, why is there a problem with getting 24-bit colors on a 24-bit
monitor with GRASS? 

-- Mark

Mark P. Line, Open Pathways              Phone: +1-206-733-6040
P.O. Box F                                 Fax: +1-206-733-6040
Bellingham, WA 98227-0296     Email: markline at henson.cc.wwu.edu

More information about the grass-user mailing list