Re: How to enforce unicode font for all charsets?

[Sergey Organov <sorganov@gmail.com>]

Robert Pluim <rpluim@gmail.com> writes:

>>>>>> On Wed, 11 Mar 2020 08:10:39 +0300, Sergey Organov <sorganov@gmail.com> said:
>
>     Sergey> Thanks, I was thinking along these lines indeed. The problem is I can't
>     Sergey> figure how exactly do I do it, provided the DejaVu Sans Mono is the font
>     Sergey> currently being set through M-x customize-face RET default, and I don't
>     Sergey> want to loose the ability to change this way the (only) font I'd like to
>     Sergey> use.
>
>     Sergey> I mean, it looks like I need to modify fontset-auto1, as M-x
>     Sergey> describe-fontset RET shows:
>
>     Sergey> Fontset: -PfEd-DejaVu Sans Mono-normal-normal-normal-*-23-*-*-*-m-0-fontset-auto1
>     Sergey> [...]
>
>     Sergey> and after some more digging, I finally tried:
>
>     Sergey> (set-fontset-font "fontset-auto1" 'windows-1251
>     Sergey>   (font-xlfd-name (face-attribute 'default :font))
>
>     Sergey> which evaluates to:
>
>     Sergey> "-PfEd-DejaVu Sans Mono-normal-normal-normal-*-23-*-*-*-m-0-iso10646-1"
>
> You'd want to use nil instead of "fontset-auto1" to affect the current
> frame's fontset, or t to affect the default fontset.

Thank you for suggestion, but still no luck. I've tried both t and nil
to no avail.

That said, for permanent customization in init file, I will need to
specify particular fontset anyway, right?

>
>     Sergey> but doesn't seem to have any visible effect. And even if that worked, it
>     Sergey> wouldn't immediately pick subsequent customization of the default face
>     Sergey> anyway?
>
> Right, fontsets are static. How often do you customize your default
> face? :-)

Admittedly not often, but there are still 2 problems:

1. When I do customize the default face, say in 1 year, and it doesn't
work, how do I find/recall why?

2. The result of (set-fontset-font) will depend on the moment of its
execution relative to application of customization of default face.

>     Sergey> What do I miss?
>
>     >> Moreover, specifying that font for any charset is probably not
>     >> a good idea, since no font covers all of Unicode.
>
>     Sergey> Maybe I should be able to express exactly this by specifying, say,
>     Sergey> "preferred font" for a fontset? I mean: "use this font, unless there is
>     Sergey> no suitable glyph, in which case turn back to the fancy methods of
>     Sergey> considering charsets".
>
> By default, set-fontset-font replaces the existing definition. You can
> pass it 'prepend' as the fifth argument to have it add to the front of
> the existing one.

This is not the same as "preferred font(s)" would be if Emacs had them.

>     Sergey> Actually, I probably do want to use only this font (and have empty
>     Sergey> rectangles or some such in case of missed glyphs). I mean some way to
>     Sergey> force Emacs to behave as if this font is the only available font in the
>     Sergey> entire system. Still no simple way?
>
> For all characters or just the windows-1251 charset? If the latter

Obviously the former. Just suppose I only install DejaVu Sans Mono font.
Nothing else. No other fonts at all. How would Emacs behave by default
in such a setup? Now I need to force such behavior in a system where
multiple fonts are installed.

>
> (set-fontset-font t 'windows-1251
>                   (font-xlfd-name (face-attribute 'default :font))
>
> should do that.

Somehow it still doesn't work for me even for windows-1251, dunno why.

-- Sergey