Re: Changing header/footer font in mm

[G. Branden Robinson]

Hi Jan,

At 2024-04-24T07:53:51+0200, Jan Eden wrote:
> On 2024-04-24 00:07, G. Branden Robinson wrote:
> > At 2024-04-21T23:52:48-0500, G. Branden Robinson wrote:
> > > For mm, what I would do is set up the mounting positions to replace
> > > Times with Helvetica.
> > > 
> > > .fp 1 HR
> > > .fp 2 HI
> > > .fp 3 HB
> > > .fp 4 HBI
> > 
> > I retract this advice.  Using ".fam H" early in the document (in
> > groff 1.23.0) is better.
> 
> This did not work in groff 1.23.0 for the header/footer issue (with
> `.fam H` as the very first request in the document), I had to use both
> requests –
> 
> .fam H
> .fp 1 H
> 
> – as suggested by Thomas.

Ah, right.  Okay.  I un-retract the advice.  Yes, Thomas was right.

The reason is that, quite apart from environment issues, groff mm is
faithful to the DWB mm tradition in that internally it refers to fonts
by mounting position rather than a named style, even though it has
cognizance of only one family.[1]  Jörgen Hägg, the author groff mm,
appears to have added some limited support for switching the font family
to his multicolumn macro extensions, MULB/MULN/MULE, but it's not clear
to me exactly how they work.  (Rather, I can read and understand the
requests just fine but I'm not sure they're necessary...?  Perhaps this
was the beginning of an unfinished idea.)

This fact is totally separate from the environment stuff I was talking
about earlier because, as I noted previously, the list of font mounting
positions is global, and consistent among all environments.

The concept of mounting positions is a fairly baroque aspect of troff
and completely, as far as I know, a consequence of the hardware design
of the C/A/T phototypesetter used by the Bell Labs CSRG.  They used this
indirection to refer to fonts because the machine itself did.  You
didn't have any idea what font's photographic plate would be loaded into
the various positions of the typesetter's mechanical carousel.  One of
your co-workers could scramble their order, ruining your document and
you had no way of knowing until it was printed.

I expect this didn't happen often, not with the imploding gaze of an
office balrog to fear...

I would prefer to wean groff mm off of explicit use of mounting
positions altogether, but doing so is not a high-urgency project.
(This also means it's good task for a contributor who wants a modestly
sized project to learn with.  :) )

Regards,
Branden

[1] I grepped and could find _no_ matches in our m.tmac for `ft [BIR]`,
    `\\f[BIR] or `\\f\[[BIR]\]`.  Replacing "BIR" with "123" is more
    fruitful.

signature.asc
Description: PGP signature