Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!mnetor!uunet!hpda!hpsal2!morrell
From: morrell@hpsal2.HP.COM (Michael Morrell)
Newsgroups: comp.text
Subject: Re: troff floating display blows away centering of caption
Message-ID: <2610002@hpsal2.HP.COM>
Date: Sat, 5-Sep-87 00:39:00 EDT
Article-I.D.: hpsal2.2610002
Posted: Sat Sep  5 00:39:00 1987
Date-Received: Sun, 6-Sep-87 09:45:08 EDT
References: <425@methods.UUCP>
Organization: Hewlett Packard, Cupertino
Lines: 41

In article <425@methods.UUCP> owen@methods.UUCP (Owen Plowman    Mr. Tech.) writes:
>pair.  All is okay so far.  The kicker is that, if I have some "pic"
>specifications in my figure, I have to use ".DF CB" in order to get a
>result that is centered on the page.  But, this blows the centering of
>the caption all over the place.  Usually, the left part of the caption
>is aligned with the leftmost item of the picture.

As I understand the CB option to .DF (or .DS), it finds the widest line
in the display (which includes the caption in your case), centers that
and then left justifies all the other lines with respect to that widest
line.  I would not use this.  My pic documentation says that the preferred
way to get centered pictures is to redefine .PS and .PE.  I use the
following:

.de PS                 \" centered pic start
.if t .sp .3
.in (\\n(.lu-\\$2u)/2u
.ne \\$1u
..
.de PE                 \" centered pic end
.in
.if t .sp .5
..

Then, one can simply use .DF with no arguments:

.DF
.PS
some
picture
here
.PE
.FG "picture caption"
.DE

The .PS and .PE macros can also be defined so that the pic centering
can be done on a case by case basis (each picture can be centered or
not).   Hope this helps,

   Michael Morrell
   {ucbvax,hplabs}!hpda!morrell