Date: Thu, 11 Dec 1997 12:15:40 +0000 (   )
From: "Gurunandan R. Bhat" <grbhat AT unigoa DOT ernet DOT in>
To: asu1 AT cornell DOT edu
Cc: Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>,
        "A. Sinan Unur" <sinan DOT unur AT cornell DOT edu>, djgpp AT delorie DOT com
Subject: Re: setting up dviwin for djgpp tex distribution
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On Wed, 10 Dec 1997 asu1 AT cornell DOT edu wrote:

> eli, thanks for your response. i must admit i have absolutely no idea 
> what is involved in writing a dvi previewer. i was looking at the dvivga 
> source last night but i am having a hard time following the flow. is 
> there any document or other source of information outlining what is 
> involved? where should i look?

Actually, one needs to interpret three file formats: 

1) the dvi file format which gives the position of each "character"
2) the pk (packed) file format that describes the character interms of 
   raster data (bitmaps)
3) the tfm file which describes the various dimensions of the "character"

Each of these file formats can be gleaned from the web sources of the
programs that interpret the corresponding file format. For example, the
web sources of the program pktype.w can be passed through "weave" to
produce a nicely documented *pascal* code that interprets a pk file. There
are corresponding interpreter programs for tfm (tfmread.w) and dvi (not 
sure about the precise file name right now) file formats. 

If you are intersted in writing a dvifile viewer, I would be happy to 
send you some relevant tex docs. I am currently doing this using 
Allegro, but having some problem in interpreting dvi \specials (eepic 
for example) as well as the positioning of diacritical marks. I would 
be happy to share my experiences.