Subject: bug#34476: fluffy whitespace in the mode-line, despite it running off the screen

From: Lars Ingebrigtsen <[email-masked]>
Date: Tue, 29 Dec 2020 16:07:50 +0100

Eli Zaretskii <[email-masked]> writes:

> You are comparing the number of characters with the window-body width,
> but the latter is measured in units of the frame's canonical character
> width, i.e. the average width of the default face's font.  If someone
> modifies the mode-line face to use a font of a different size, or even
> has enough wide characters there to violate the "1 character = 1
> column" assumption, that test will produce either truncated mode-line
> string or will unnecessarily squeeze spaces from it.

Yup.  I was also not quite sure of the selected_window itself -- can the
mode line be updated while another window is selected?  But I tried
various scenarios, and I couldn't get it to pick the wrong window to do
the computation on.  So perhaps that bit is OK?

> I understand the difficulty of doing TRT, but perhaps we should at
> least document this limitation, so that users don't expect too much
> from this feature, and we don't get bug reports that will be hard to
> fix?

Yup; will do.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no