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From: moss@ptsfa.UUCP
Newsgroups: comp.text
Subject: Re: Inserting text directly in ditroff output
Message-ID: <3696@ptsfa.UUCP>
Date: Fri, 30-Oct-87 11:26:09 EST
Article-I.D.: ptsfa.3696
Posted: Fri Oct 30 11:26:09 1987
Date-Received: Sun, 1-Nov-87 09:01:14 EST
References: <3457@trwrb.UUCP>
Reply-To: moss@ptsfa.UUCP (MiniComputer Ops Support)
Organization: Pacific * Bell, San Ramon, CA
Lines: 57
Keywords: ditroff, postprocessor

Sorry for the net response, e-mail keeps bouncing...

>We have an old version of ditroff that doesn't seem to be able to give a
>string directly to the postprocessor...

Scott,
	Ditroff (all versions that I know of) does not have any special
output command for transparent data, but it does have an escape sequence
that allows passing source lines transparently to ditroff's output.  This
is the transparent line escape "\!".  Anything that follows a \! will be
passed through (without the \!) directly to ditroff's output.  The trick
is to pass through something that is special to the postprocessor, but is
not an ordinary ditroff command such as "c", "x", etc.  For example, say
your preprocessor recognized a "B" (which is not one of the ditroff output
directives (commands)) to output a bitmapped graphic image.  The following
line appearing in the source:

\!B /usr/bitmaps/someimage 300 1200 350...

would pass the line:

B /usr/bitmaps/someimage 300 1200 350...

throught to ditroff's output.  Any letter or character that is not one
used by ditroff could be used.  It is up to the postprocessor to strip
out the line and interpret it.

Also, your version of ditroff may or may not have the ".cf" request
(copy file).  This is the equivilant of a "transparent file" request:

.cf filename

The contents of "filename" are sent unmodified to ditroff's output. This
could be useful for sending multiline output to a postprocessor.  As an
example, suppose a postprocessor recognized the lines:

X-Begin
X-End

as enclosing data that is to be passed directly to the output device.
Then the file "mydata" might contain:

X-Begin
any data here that is meaningful
to the printer including escape sequences
and special characters (metacharacters).
X-End


Enough already.  I think you get the idea.  If you have any questions,
please feel free to call me or send me mail direct.

					Ken Keirnan
-- 
Minicomputer Operations Support Staff	/ !pt05a!kk1	(415) 823-3911
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