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                     =###=    -*##*    o**o   ##** .**-
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     Zgv v2.1 - GIF and JPEG viewer, for PCs with VGA running Linux

       Copyright (C) 1993,1994 Russell Marks for improbabledesigns


This README covers description and use of the programs. See README.src in
the source distribution, or README.bin in the binaries distribution for
other details. (In fact, you should read those first.) CHANGES describes the
changes made since the most recent publicly released version, and CHANGELOG
describes differences between all versions, so if you are upgrading from an
old version, check those files out too. The file BUGS describes known bugs
which may affect your use of the programs.

NB: All documentation files other than this README have been moved to the
'doc' subdirectory.


Distribution and Conditions of Use (License)
--------------------------------------------

These programs, and any output from them, can be freely used and
distributed. No modified versions of any or all of the programs, or
derivative works, may be distributed unless specifically permitted by the
author, with the following exception; if the modification is reverseable and
intended in good faith to aid distribution (common occurances include
using 'tar', compression software, etc.), then it is permitted.  

I supply each of the programs on an 'as is' basis in the hope that they will
be useful but with absolutely no warranty of any kind, and assume no
liability or responsibility for any ill they may cause whatsoever.  


Description of the Programs
---------------------------

'zgv' is a viewer which views GIF87a, GIF89a, JPEG/JFIF and PBM/PGM/PPM
files on a standard VGA and some SVGAs, with a full-screen file selector
front-end. It can also be used as a simple command, by 'zgv filename', which
bypasses the front-end.

'tnpic' produces a JPEG file containing small versions (thumbnails) of other
picture files. Once the programs are installed, do 'man tnpic' for more
details. (Or if they aren't installed, you could do 'nroff -man
tnpic.1 | less'.) Tnpic does not yet support P?M files.



You should read the TeX file 'zgv.tex' for more details - try 'xdvi
zgv.dvi', if that doesn't work, just reading 'zgv.tex' as a text file isn't
too painful. Where the TeX file and the man page differ, the TeX file should
be assumed to be up to date and correct. The file '24bit.txt' describes how
the 24-bit handling works, hopefully. I apologise in advance for the fairly
confusing nature of the documentation, but hacking up zgv is a lot more fun
than writing docs as you can probably imagine. :)


A note about /dev/tty0
----------------------

/dev/tty0 is an alias to the current console which zgv needs to have read
access to. When you do 'make install', a "chmod a+r /dev/tty0" is
automatically done. Having thought about this for a while, I can see no
security problems involved. After all, /dev/tty0 is analogous to /dev/tty,
which is (to my knowledge) generally world-readable.


Share and enjoy! 

- Russell Marks (rm1ajy2@gre.ac.uk)
