Re: About how centering affects horizontal movements

[Walter Alejandro Iglesias]

On Sat, Jan 18, 2025 at 08:17:11PM +0100, onf wrote:
> On Sat Jan 18, 2025 at 8:09 PM CET, onf wrote:
> > [...]
> > > \Z'123456789'
> > > .rj
> > > 123456789
> >
> >   $ groff -Tutf8 | sed "s/ /'/g"
> >   ''''''''''''''''''''123456789
> >   '''''''''''''''''''''''''''''''123456789
> >
> > Huh. I get what you meant by "right-justified against what?" now.
> > It might just be that my conclusion of \Z causing right justification
> > when centering is enabled was wrong. I don't actually know what groff
> > does; its source code is too complicated for me to read.
> >
> > By the way, I tried this with neatroff and it works as expected:
> >   $ neatroff/roff -F. << EOF | neatpost/pdf -F. -pa4 > t.pdf
> >   .pl 29.7c
> >   .ll 21c
> >   .po 0
> >   .ad c
> >   \Z'123456789'
> >   .br
> >   .ad r
> >   123456789
> >   EOF
> >
> > The first 123456789 is indented by half the line length, whereas the
> > second one is set flush against the right margin.
> > [...]
> 
> Ugh. It took me too long to realize what's going on, but neatroff's
> behavior explains it. The line is not right adjusted. It's centered,
> but the contents of \Z don't contribute to the line's width, so it's
> an equivalent of \& being centered. In other words, the text enclosed
> with \Z is indented by half the line length.

That's what I thought. :-)

> 
> ~ onf
> 

-- 
Walter