bug#25216: 26.0.50 [regression]; Curly quotes are not found in some sizes of ‘Terminus’ font

[Eli Zaretskii <eliz@gnu.org>]

> From: Dmitry Alexandrov <321942@gmail.com>
> Cc: larsi@gnus.org,  25216@debbugs.gnu.org
> Date: Wed, 20 Nov 2019 18:01:48 +0300
> 
> Eli Zaretskii <eliz@gnu.org> wrote:
> >> > There was no response to this -- was any further progress made?
> >> 
> >> On my side: sorry, no.  I am fine with the workaround:
> >> 
> >> 	Emacs.fontBackend: xft
> >> 
> >> (in ~/.Xresources).
> >
> > Could you try the master branch, after making sure you have HarfBuzz installed?  The xft font backend is going to be much less important starting with Emacs 27, so I'd like to know whether this problerm exists with HarfBuzz
> 
> Yes, the problem is still here, symptoms are the same, except that Terminus is now loaded via harfbuzz:
> 
> 	xfthb:-xos4-Terminus-normal-normal-normal-*-18-*-*-*-c-100-iso10646-1
> 	   ^^
> 
> The same workaround works as well:
> 
> 	Emacs.fontBackend: xfthb

I've built the latest version 4.48 of the Terminus font on MS-Windows
and tried it with Emacs 27.  I couldn't reproduce the problem reported
with the xft or xfthb font backends: no matter what size of the font I
tried, the curly quote characters came from the same font.  I do see
that, since this font is bitmapped, i.e. not TrueType, Emacs on
Windows uses the GDI font backend to display it, not the default
HarfBuzz backend.

So I think what you see is something specific to the libxft2 library.
And since this discussion identified at least 2 workarounds: either
customize the fontset, or force the single xft backend in .Xresources,
I think this bug can be closed now.

Thanks.