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From: henry%angel@Sun.COM (Henry McGilton -- Software Products)
Newsgroups: comp.text
Subject: Re: Shaded Boxes in PIC
Summary: troff is not a graphics editor
Message-ID: <127725@sun.Eng.Sun.COM>
Date: 10 Nov 89 18:57:58 GMT
References: <546@dcdwest.UUCP>
Sender: news@sun.Eng.Sun.COM
Lines: 38

In article <546@dcdwest.UUCP>, benson@dcdwest.UUCP (Peter Benson) writes:
    > I would like to know how to shade a box or other closed form
    > in pic.
In principle this cannot be done.  pic  is a preprocessor
for  troff, and  troff  is not a fully fledged graphics
editor.  End of debate.

    > Since pic generates PostSvript
The version of  pic  I have here generates  troff  drawing
requests and other things.  While it's true various people
have experimented with making  pic  crank out PostScript, I
don't know of any widely available version of this.
    > and shded closed figures are possible in PostScript,
    > there is a way, albeit
    > with the pic equivalent of patching the machine code.
As far as I can tell, although the minor premise is correct, the
major premise is incorrect, and therefore the conclusion is a
non sequitur.

The  'pic  equivalent of patching the machine code' would be to
emit PostScript code from the  pic  side via  troff's  transparent
throughput machinery (the  \!  escape sequence).  However,  pic
doesn't understand this escape sequence, so that avenue is also
closed to you.
    > Is there some better way?

In closing, I'm not at all sure it's possible to do what you want
in a simple way (not requiring modifications to both  pic  and
troff).  But if anyone else knows better I'd be happy to learn
something new.

	............ Henry

+------------------+------------------------+---------------------------+
| Henry McGilton   | I saw the future,      | arpa: hmcgilton@sun.com   |
| Sun Microsystems | and it didn't work.    | uucp: ...!sun!angel!henry |
| Mt. View, CA     |                        |                           |
+------------------+------------------------+---------------------------+