bug#19194: 24.4.50; `window-body-width' is not dynamic relative to font size changes

[Joe Corneli <holtzermann17@gmail.com>]

On Wed, Nov 26 2014, Eli Zaretskii wrote:

> One simple technique is to measure everything in pixels, but I don't
> know at this point whether this will solve your use case.

That would probably do it for me, yes.

On Wed, Nov 26 2014, Stefan Monnier wrote:

>> function to return the "actual" number of columns.
>
> How do you define "actual number of columns" in the presence of
> proportional fonts, images, and text of variable size?

I hadn't considered anything but fixed width fonts with uniform size --
but, for instance, the width could be reported in em-length units.

If people switch fonts mid-line, that's clearly a pain - but "ems" could
be defined relative to point-size-at-point, and would accordingly return
an accurate *length*.  In the general not the same as the "actual number
of columns" - but possibly still of use.