Re: min-width display property, but with padding at the start

[Spencer Baugh <sbaugh@janestreet.com>]

Eli Zaretskii <eliz@gnu.org> writes:

>> From: Spencer Baugh <sbaugh@janestreet.com>
>> Date: Tue, 20 Aug 2024 08:09:51 -0400
>> 
>> >> Is there a way to achieve this with display properties?
>> >
>> > Why do you need display properties?  What's wrong with
>> >
>> >   (format "%5s" THE-STRING)
>> >
>> > ?
>> 
>> That is probably what I'll do if I can't find another solution, but
>> doing it with display properties works with non-fixed-width characters
>> and faces, which a user might have configured.
>
> Using variable-pitch fonts on the mode line is not recommended, as the
> results could be problematic around fields that change dynamically.
> The min-width property was introduced to make that easier during the
> short period when we considered switching to variable-pitch font by
> default, but we later decided not to do that for several reasons.

Ah, okay, that makes sense.  I'll just use a format invocation as you
described, then.

> Are there many people who use variable-pitch fonts on the mode line?
>
>> If simply padding with spaces sufficed, the display properties in
>> (info "(elisp) Specified Space") would have little reason to exist.
>
> As an alternative to min-width, you could use a :space display spec
> whose width you calculate in Lisp, given string-width of the string
> you want to pad.  I think this should work.

Yes, that makes sense as a way to support variable-pitch fonts (although
probably a little less reliable than something supported directly by the
display engine)