Re: Variable-width font indentation (was: What improvements would be truly useful?)

[Eli Zaretskii]

> From: Richard Stallman <address@hidden>
> Date: Mon, 05 Mar 2018 08:11:38 -0500
> Cc: address@hidden, address@hidden, address@hidden
> 
> Changing Emacs to handle indentation and alignment with
> variable-width fonts would be an important and useful change.
> Certain kinds of use would make sense, which currently don't.

This has come up several times, and I think I asked at least once what
does it need to entail.  It would be helpful to have the answer to
that, which will have to be the result of looking at the relevant Lisp
code and figuring out which primitives/subroutines will need to be
taught fractional column values.

Emacs already knows how to align text at pixel resolution (which is
easy to express in fractions of the width of the default face's font),
and in fact already does so when it displays TAB characters on GUI
frames.  We have the 'space' display property to do the same with
characters other than a TAB.

So what else is needed?  Can someone who is familiar with indent.el
please tell?