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From: pjbk@hwcs.UUCP (Peter King)
Newsgroups: net.unix-wizards,net.text
Subject: Re: (more) nroff questions on italics/underscore
Message-ID: <263@hwcs.UUCP>
Date: Mon, 5-Nov-84 12:45:54 EST
Article-I.D.: hwcs.263
Posted: Mon Nov  5 12:45:54 1984
Date-Received: Sat, 10-Nov-84 05:52:05 EST
References: <925@opus.UUCP> <926@opus.UUCP>
Organization: Computer Sci., Heriot-Watt U., Scotland
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Xref: mcvax net.unix-wizards:6554 net.text:85

In response to the original question about the use of a hard-wired
'_' character to do italics/underscore in nroff.
	I don't know why it is done that way, but it does give
	onesome possibilities of distinguishing italic font
	from any thing the user could have typed in his
	source file.
a)	The technique would be:- let none of the entries in the table
	use '_' at all, but use some other character using an octal escape
	sequence, which can be converted by a filter to the '_'
	character.

b)	The same filter can be used to interpret '_^Hx' as an 'x'
	in the device's italic/underlined font.

	We have a set of tables and a filter that does b) but not a)
	for an Anadex printer.

2)	I also ran into this problem when trying to write a table
	to drive the Anadex printer's proportional font.
	nroff seems to have simple typewriter style widths
	built into the code (as assumptions).
	Attempts to define the t.char as a smallish distance
	apart from running into accuracy problems (since 1/240
	was not a factor of the distance needed) also
	caused floating point exceptions all over the show.

	I'm afraid the problem still exists here, and we cannot
	use the proportional fonts from 'nroff'.
	(Perhaps 'ditroff' will be able to do it)