bug#81570: 31.0.90; window-text-pixel-size sometimes does not correctly determine the width of characters with face attribute :box

Eli Zaretskii <[email protected]> Fri, 07 Aug 2026 14:30:48 +0300
Newsgroups gmane.emacs.bugs
Message-ID <[email protected]>
> Cc: [email protected]
> From: Sean Whitton <[email protected]>
> Date: Fri, 07 Aug 2026 11:56:05 +0100
> 
> retitle 81570 30.1; window-text-pixel-size sometimes does not correctly determine the width of characters with face attribute :box
> thanks
> 
> Markus Triska [06/Aug 11:24pm +02] wrote:
> > In Emacs versions before d98afc1019d9f177dd05042371dd8239b7901d47, both
> > tests I posted work as expected, yielding 2 and (2 . 2), respectively.
> 
> So this problem was not introduced by Emacs 31.

This regression (if it is a regression: I'm not yet sure) was
introduced in Emacs 28.1.