bug#54564: 29.0.50; [PATCH] Use gsettings font rendering entries for pgtk builds

[Po Lu via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

Eli Zaretskii <eliz@gnu.org> writes:

> Does the below fit the bill?
>
>    clear_face_cache (true);
>
> Or did you mean to do this only on a single frame (or on specific
> selected frames)?  Then looking inside clear_face_cache will tell you
> how to do that.

It should be done for each frame on every display, so clear_face_cache
probably does fit the bill.  (Though perhaps clear_font_cache on each
window system frame by itself will be enough?)

> And one more thing: care should be taken if this is done in response
> to some async notification, because clearing all the faces will need a
> thorough redisplay.  Most probably all the affected frames need to be
> marked as "garbaged".

Thanks.  Pieter, do you need any help in implementing the feature along
those lines?

> I don't see any references to that variable in the patch you are
> discussing.  And its name and doc string don't seem to give any clue
> that it's relevant to this issue.  Is this only for fixed-pitch fonts?

No, this is supposed to work for all fonts.

> Yes, I think so.

Sure, thanks.