Path: utzoo!utgpu!cunews!micor!latour!ecicrl!clewis
From: clewis@ferret.ocunix.on.ca (Chris Lewis)
Newsgroups: comp.lang.postscript
Subject: Re: including postscript files in troff files
Message-ID: <1433@ecicrl.ocunix.on.ca>
Date: 23 Apr 91 16:11:46 GMT
References: <5353@ns-mx.uiowa.edu> <1595@vidiot.UUCP> <1383@ecicrl.ocunix.on.ca> <1612@vidiot.UUCP> <1407@ecicrl.ocunix.on.ca> <1634@vidiot.UUCP>
Organization: Elegant Communications Inc., Ottawa, Canada
Lines: 59

In article <1634@vidiot.UUCP> brown@vidiot.UUCP (Vidiot) writes:
>In article <1407@ecicrl.ocunix.on.ca> clewis@ferret.ocunix.on.ca (Chris Lewis) writes:

><Game #1 (simplified):
><	- There is no CAT code corresponding to the letter 'M'.  Eg: in
><	  CAT output, 0115 can never occur.
><	- So, you put this in your CAT troff input:
><	    .tm "Mhello there"
><	- And you use troff thusly:
><		(troff -t ... 2>&1) | cat-2-whatever

>I can't find my docs on the CAT output.  In any event, there obviously has
>to be a letter M, otherwise there would have been many screwed up documents.

>I have to assume that you mean the octal code 115 is not used in the CAT
>output codes.  This happens to correspond to the letter M.  Therefore, if
>that code appears in the CAT output (actually it doesn't), then it means
>something special to the post-processor.

Sorry about that - I'll rephrase: according to cat.5 (mine is written by Henry
Spencer...) the octet 0115 is not valid in the output of CAT troff.  Ie:
an unused opcode.  In ASCII "M" is 0115, but CAT output does not contain
ASCII codes for characters.  Except when you merge ".tm" output into
the CAT codes... (consider yourself lucky that one of the unused codes
in CAT language is a 7-bit ascii character that can be uttered into the
input of CAT troff.  If the unused ones were all 8-bit on, we'd probably
have been out of luck)

>Neat little trick.

Thanks...

>The PostScript inclusion files that I have have fixed positions in the
>PostScript file and they are not meant to be positioned by the troff itself.
>It is meant to be positioned with PostScript code.  That way the troff source
>doesn't have to worry about where the characters are positioned.  But, there
>are obviously many situations where this does have to happen.

The basic mechanism (file inclusion, passthru) doesn't do the positioning.
Without other measures (psfig, current point etc.) the postscript would
be of necessity absolute positioning.  The ".tm Mf" and ".tm Mp" are merely
kludgey renditions of \X'f..' and \X'p..' and, by themselves, don't
do anything fancier than file inclusion and passthru. 

Psroff contains samples of both - "form" overlay (letterhead drawing via inclusion
of "absolute" postscript.), and use with psfig is an example of floating scalable
pictures with a consistent (with the rest of the troff family of software)
interface.  Use of Psfig (either with psroff (CAT/ditroff) or any ditroff to
postscript converter) gives you both.

>Thanks for the info.  I will keep it handy.  Boy, the games people play to
>get around problems. :-)

No kidding!
-- 
Chris Lewis, Phone: (613) 832-0541, Domain: clewis@ferret.ocunix.on.ca
UUCP: ...!cunews!latour!ecicrl!clewis; Ferret Mailing List:
ferret-request@eci386; Psroff (not Adobe Transcript) enquiries:
psroff-request@eci386 or Canada 416-832-0541.  Psroff 3.0 in c.s.u soon!