bug#53718: 29.0.50; Recent change to font hinting in --with-pgtk build

[Protesilaos Stavrou]

Dear maintainers,

I built Emacs with commit 02054d9cd1f5c6a5ca3555207235522532477e10 using
--with-pgtk and have noticed that there is a change to the hinting of
the fonts relative to commit d25cb37694de446e6dd1095f489d5436ea9e20ae.

Please refer to the attached screenshots which compare the two commits
using Hack and Source Code Pro, respectively.  The differences are
subtle, though you can see how the 'm' is affected.

The hinting is inconsistent.  Even in this very message.  Notice the
quotes in this 'Hack' with the one below which has a thinner first quote
and thicker second one:

'Hack'

All the best,
Protesilaos

* * *

In GNU Emacs 29.0.50 (build 5, x86_64-pc-linux-gnu, GTK+ Version 3.24.31, cairo 
version 1.17.4)
 of 2022-02-01 built on kronos
Repository revision: 02054d9cd1f5c6a5ca3555207235522532477e10
Repository branch: makepkg
System Description: Arch Linux

Configured using:
 'configure --prefix=/usr --sysconfdir=/etc --libexecdir=/usr/lib
 --localstatedir=/var --mandir=/usr/share/man --with-gameuser=:games
 --with-sound=alsa --with-modules --without-libotf --without-m17n-flt
 --without-gconf --without-gsettings --with-native-compilation
 --with-xinput2 --with-pgtk --without-xaw3d --with-sound=no
 --without-gpm --without-compress-install
 '--program-transform-name=s/\([ec]tags\)/\1.emacs/'
 'CFLAGS=-march=x86-64 -mtune=generic -O2 -pipe -fno-plt -fexceptions
 -Wp,-D_FORTIFY_SOURCE=2 -Wformat -Werror=format-security
 -fstack-clash-protection -fcf-protection'
 LDFLAGS=-Wl,-O1,--sort-common,--as-needed,-z,relro,-z,now'

Configured features:
ACL CAIRO DBUS FREETYPE GIF GLIB GMP GNUTLS HARFBUZZ JPEG JSON LCMS2
LIBSYSTEMD LIBXML2 MODULES NATIVE_COMP NOTIFY INOTIFY PDUMPER PGTK PNG
RSVG SECCOMP SQLITE3 THREADS TIFF TOOLKIT_SCROLL_BARS WEBP XIM GTK3 ZLIB

-- 
Protesilaos Stavrou
https://protesilaos.com

hack-emacs-commit-02054d9cd1f5c6a5ca3555207235522532477e10.png
Description: PNG image

hack-emacs-commit-d25cb37694de446e6dd1095f489d5436ea9e20ae.png
Description: PNG image

source-code-pro-emacs-commit-02054d9cd1f5c6a5ca3555207235522532477e10.png
Description: PNG image

source-code-pro-emacs-commit-d25cb37694de446e6dd1095f489d5436ea9e20ae.png
Description: PNG image

inconsistent-hinting-quotes.png
Description: PNG image