From: <sethf@ATHENA.MIT.EDU>
Date: Tue, 23 May 89 00:07:47 EDT
Message-Id: <8905230407.AA06190@M11-111-2.MIT.EDU>
To: bgardner@ATHENA.MIT.EDU
Subject: Re: color xpix
Cc: paul@ATHENA.MIT.EDU

	The program currently running in the fishbowl is a color idle
display that makes use of color xpix. The images appear automatically
when all users of a workstation have logged out, and after it has been
idle for a period of time. The automatic display of images is part of
the 'toehold' program. 'toehold' performs miscellaneous activation and
deactivation jobs. It is not ordinarily run by users. The images
themselves, and some display program, can be found in the 'pictures'
locker.
	The files are in X11 color window dump format. These have '.x11'
in their name. They are stored in a compressed form, so the names end in
'.Z'. There may also be file ending in '.gif' around. They are in
Compu$erve Graphics Interchange Format. At the moment almost all the
color xpix are converted GIF files.
	Displaying color images is not a straightforward task. The
standard X window undump program 'xwud' doesn't handle them well.
The most reliable method is probably
	zcat file.x11.Z | xpand -a | xtoxim | xim
	The last two programs (xtoxim and xim) can be found in the
'visual' locker. They were written by Philip Thompson (phils@athena).
xpand is in the 'pictures' locker (currently only compiled for vaxen)
The xpand -a part can be omitted for faster execution. It expands the
image to best cover the entire screen. This is not the display method I
use, but is the one I hope will require the least knowledge about the
limitations and aggravations of color X.
	Creating a color xpix from one of your own images requires
"only" that the image be translated into X11 color window dump format.
This mostly requires study of the format of the header (which can be
found in /usr/include/X/XWDFile.h) and the source to 'xwd' and 'xwud'
(attach x11 to examine). 
	I don't know of any color format that corresponds to the
'C-structure'like bitmap format.

================
Seth Finkelstein
sethf@athena.mit.edu
sethf%athena.mit.edu@mit-eddie.UUCP
mit-eddie!mit-athena!sethf