bug#37667: 27.0.50; Tab Bar display problems with more than 5 tabs

[Eli Zaretskii]

> From: Juri Linkov <juri@linkov.net>
> Cc: Eli Zaretskii <eliz@gnu.org>,  37667@debbugs.gnu.org
> Date: Mon, 14 Oct 2019 01:31:00 +0300
> 
> BTW, is there a reason why the mode line doesn't use a variable-pitch font?

By default?  It would cause unpleasant horizontal movement of text,
e.g. when the line number changes.  Also, many variable-pitch fonts
have a very thin glyph for SPC, so different fields could appear as a
single field, another visual problem.

Of course, nothing prevents people from customizing the face to use
whatever font they like.

> I tried a variable-pitch font for tab bars, and it looks good
> and makes tab widths smaller, so more tabs fits into the tab-bar.

Could be a good idea.  Toolkit menu bars definitely use variable-pitch
fonts on most systems.

> But maybe non-monospace fonts might complicate calculation of various
> text lengths when trying to fit tabs into the tab-bar.

Emacs never assumes a face uses fixed-pitch font when it calculates
the various metrics.  So this cannot be a problem (barring bugs).