Hello All,

Here's the second version of my patch to use the gsettings for font
rendering:

- Every change is scoped to the pgtk build. 
- Changing settings redisplay dynamically by hooking into the
cached_font_ok field of the cairo font driver and storing a font-render
event upon a gsettings change.
- Formatting is now in line with the gnu c style.
- Commit message was split into multiple parts per changed file.

When playing around with the font settings, I noticed that cairo/pgtk
doesn't seem to use the subpixel antialias (e.g. cleartype style)
rendering setting, even though that option is set. I'll investigate
further, it doesn't look like a regression due to this patch, but
existing behavior.

Kind Regards,

Pieter

On Sun, 2022-03-27 at 08:59 +0800, Po Lu wrote:
> Pieter van Prooijen <pieter.van.prooijen@teloden.nl> writes:
> 
> > Hello All, 
> > 
> > Thanks for looking into my patch!, I'll fix the formatting issues
> > you
> > mentioned and narrow the changes to the HAVE_PGTK define in the
> > various
> > source files, so it's is only present for that build.
> 
> Indeed, and thanks for working on Emacs as well.
> 
> > Not sure about having this functionality controlled by a user
> > defined
> > variable (as is possible with using the system font), as far as I
> > know,
> > the current cairo X backend doesn't have this as well, it will
> > always
> > use the gsettings/xrdb defined parameters for rendering.
> 
> We don't support using the PGTK build on X Windows anyway, so that's
> not
> a real problem.  Besides, manually specified font options will
> override
> whatever Cairo thinks is best.
> 
> > Regarding the re-rendering upon a config change, I'll have a look
> > at
> > the options mentioned (clearing the font cache and marking each
> > frame
> > for redisplay), but that will probably be a separate patch.
> 
> I think it would be best to have that feature as part of this change.