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From: liam@cs.qmc.ac.uk (William Roberts)
Newsgroups: net.text
Subject: Re: ditroff transparent command
Message-ID: <139@cs.qmc.ac.uk>
Date: Mon, 21-Apr-86 06:31:57 EST
Article-I.D.: cs.139
Posted: Mon Apr 21 06:31:57 1986
Date-Received: Thu, 24-Apr-86 07:17:53 EST
References: <23@tictoc.oz> <1005@mcvax.UUCP>
Reply-To: liam@qmc-cs.UUCP (William Roberts)
Organization: CS Dept, Queen Mary College, University of London, UK.
Lines: 36
Keywords: ditroff bitmap post-processor

Summary:
Expires:
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Xpath: ukc eagle


You don't need a pre-processor to turn
        .BM xsize ysize
into    .fl
        .nr x \n(.o+\n(.i
        \!V\n(nl
        \!H\nx
        \!x B file-name

A Ditroff macro will do it perfectly well! A little care with
the \ are necessary, but what you want is probably:

        .de BM
        .fl
        .nr x \\n(.o+\\n(.i
        \\!V\\n(nl
        \\!H\\nx
        \\!x B filename
        ..

I didn't know you could use \n commands in \! - that is a
really useful feature for this sort of thing.

NOTE: this will blow any post-processor that doesn't know about
your B device control command.  If you want to extend the
capabilities of you postprocessor, USE A COMMENT CONVENTION!
Changing the "x B filename" bit into "#B filename" doesn't make
life too hard for the postprocessor, and guarantees that your
files can be sensibly handled by other peoples' postprocessors.
Since Ditroff doesn't know about your bitmaps, you have to
leave a space for it anyway.
-- 

William Roberts                 ARPA: liam@UK.AC.qmc.cs
Queen Mary College              UUCP: liam@qmc-cs.UUCP
LONDON, UK