Subject: bug#43058: closed (Re: bug#43058: 27.1; Support for other colour font formats)

From: [email-masked] (GNU bug Tracking System)
Date: Mon, 26 Sep 2022 01:06:01 +0000

Your bug report

#43058: 27.1; Support for other colour font formats

which was filed against the emacs package, has been closed.

The explanation is attached below, along with your original report.
If you require more details, please reply to [email-masked].

-- 
43058: https://debbugs.gnu.org/cgi/bugreport.cgi?bug=43058
GNU Bug Tracking System
Contact [email-masked] with problems

Subject: Re: bug#43058: 27.1; Support for other colour font formats
From: YAMAMOTO Mitsuharu <[email-masked]>
To: Eli Zaretskii <[email-masked]>
Cc: [email-masked], [email-masked]
Date: Mon, 26 Sep 2022 10:05:19 +0900
List-Id: <debbugs-submit.debbugs.gnu.org>

On Sun, 25 Sep 2022 17:03:22 +0900,
Eli Zaretskii wrote:
> 
> > In principle, some other fonts whose formats can be handled by the
> > current Emacs and cairo might have been inadvertently rejected
> > (althogh I don't have any concrete examples).
> > 
> > Also, the latest version of OpenMoji Color no longer has the average
> > width problem.  So, it is not rejected even without the patch, and its
> > glyphs are not displayed on the current Emacs and cairo anyway.
> 
> OK, thanks.  I think on balance this means we should install this, so
> please push to the master branch.

Done.  According to Peter, the patch enables us to display some COLRv0
variant of OpenMoji Color font on Emacs.  (I also confirmed that with
cairo 1.17.4).  So closing the bug.

				     YAMAMOTO Mitsuharu
				[email-masked]

Subject: 27.1; Support for other colour font formats
From: Peter Oliver <[email-masked]>
To: [email-masked]
Date: Wed, 26 Aug 2020 13:24:05 +0100
List-Id: <debbugs-submit.debbugs.gnu.org>

As I understand it, there are four competing standards for colour in TFF fonts: CBDT (Google), COLR (Microsoft), SBIX (Apple) and SVG (W3C).

I have tried CBDT, COLR and SVG in Emacs 27.1 on Fedora 32, and only CBDT works for me.

Gnome on Fedora 32 supports both CBDT and COLR, suggesting that the underlying libraries have the necessary support for COLR.

CBDT is a bitmap format, whereas COLR is a vector format; it would be good to be able to support both.  Further, the existence of https://github.com/googlefonts/colr-gradients-spec implies that Google could be considering switching from CBDT to COLR, suggesting the possibility that the CBDT format could become obsolete.

The NEWS file for Emacs 27.1 says:
“Multicolor fonts such as "Noto Color Emoji" can be displayed on
Emacs configured with Cairo drawing and linked with cairo >= 1.16.0.”
I would submit a patch to change this to mention that only CBDT is currently supported, but I’m not sure if that’s true on, e.g., Windows or MacOS.

In GNU Emacs 27.1 (build 1, x86_64-redhat-linux-gnu, GTK+ Version 3.24.21, cairo version 1.16.0)
 of 2020-08-20 built on buildvm-x86-24.iad2.fedoraproject.org
Windowing system distributor 'Fedora Project', version 11.0.12008000
System Description: Fedora 32 (Workstation Edition)

Configured using:
 'configure --build=x86_64-redhat-linux-gnu
 --host=x86_64-redhat-linux-gnu --program-prefix=
 --disable-dependency-tracking --prefix=/usr --exec-prefix=/usr
 --bindir=/usr/bin --sbindir=/usr/sbin --sysconfdir=/etc
 --datadir=/usr/share --includedir=/usr/include --libdir=/usr/lib64
 --libexecdir=/usr/libexec --localstatedir=/var
 --sharedstatedir=/var/lib --mandir=/usr/share/man
 --infodir=/usr/share/info --with-dbus --with-gif --with-jpeg --with-png
 --with-rsvg --with-tiff --with-xft --with-xpm --with-x-toolkit=gtk3
 --with-gpm=no --with-xwidgets --with-modules --with-harfbuzz
 --with-cairo --with-json build_alias=x86_64-redhat-linux-gnu
 host_alias=x86_64-redhat-linux-gnu 'CFLAGS=-DMAIL_USE_LOCKF -O2 -g
 -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2
 -Wp,-D_GLIBCXX_ASSERTIONS -fexceptions -fstack-protector-strong
 -grecord-gcc-switches -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1
 -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64 -mtune=generic
 -fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection'
 LDFLAGS=-Wl,-z,relro
 PKG_CONFIG_PATH=:/usr/lib64/pkgconfig:/usr/share/pkgconfig'

Configured features:
XPM JPEG TIFF GIF PNG RSVG CAIRO SOUND DBUS GSETTINGS GLIB NOTIFY
INOTIFY ACL LIBSELINUX GNUTLS LIBXML2 FREETYPE HARFBUZZ M17N_FLT LIBOTF
ZLIB TOOLKIT_SCROLL_BARS GTK3 X11 XDBE XIM MODULES THREADS XWIDGETS
LIBSYSTEMD JSON PDUMPER GMP

Important settings:
  value of $LANG: en_GB.UTF-8
  value of $XMODIFIERS: @im=ibus
  locale-coding-system: utf-8-unix

-- 
Peter Oliver