Hello, 

When using the pgtk build of emacs under Wayland/Ubuntu, I noticed that
the font hinting was different from the regular X (Ubuntu supplied)
version of emacs.

I have the gsettings config for font hinting set to "full" on my
system, using the fonts tab in the gnome-tweaks tool.

It looks like Cairo defaults to the "slight" hinting setting when using
the Wayland backend for display and will only use the gsettings config
when rendering to an X backend, when it reads the current font settings
from xrdb.

I've attached a patch (against
380f0443b288c68df3762ee20d78719f08dd92ff) which applies the font
entries from gsettings (if present) when creating a font in Cairo.

Note that this patch won't dynamically re-render when emacs is already
running (like it does when changing the system font).
I made an attempt to hook into the gsettings change callback, but could
not force a re-creation of the font with the changed parameters,for
instance using a 'font-render' config changed event. Any pointers on
how to achieve this?
 
Do you think if this patch is a good approach to get the pgtk build to
use the system preferences for font hinting and anti-aliasing?

Kind Regards,

Pieter van Prooijen