Re: emacs-27 60c84ad: ; * etc/TODO: Fix last change.

[Eli Zaretskii <eliz@gnu.org>]

> From: Robert Pluim <rpluim@gmail.com>
> Cc: monnier@iro.umontreal.ca,  emacs-devel@gnu.org
> Date: Wed, 04 Mar 2020 08:23:33 +0100
> 
> >>>>> On Tue, 03 Mar 2020 18:06:06 +0200, Eli Zaretskii <eliz@gnu.org> said:
>     >> What should be done here? Create another char table analagous to
>     >> char-script-table, add all the emojis from emoji-data.txt to it, and
>     >> check whether the char is in that table in fontset.c:face_for_char?
> 
>     Eli> I think it would be simpler and cleaner to define a new script,
>     Eli> 'emoji', and update admin/unidata/blocks.awk to produce it for the
>     Eli> relevant blocks (including Variation Selectors, btw).  Then no change
>     Eli> is needed in face_for_char, since that is only in effect for the
>     Eli> 'symbol' script.  As a nice bonus, this will also allow a much easier
>     Eli> customization of the fontsets, so that fonts for symbols can be
>     Eli> different from fonts for emoji.
> 
> Hmm, but a character can only have one script, no?

Yes, but why would we need the Emoji to belong to more than one
script?

> That would put Emacs at odds with Blocks.txt, I guess thatʼs why
> Unicode implemented this using character properties. Having said
> that, we already donʼt exactly follow Blocks.txt anyway.

Exactly.  We only follow Blocks.txt when a block corresponds to some
script, because scripts have a meaning for font selection.  But
'symbol' is not a script in Unicode, it's entirely our own invention,
and we lump there many blocks.  I see no problem with moving Emoji out
of there into their own script.

> Ancillary question: what fonts should we use in the default fontsets
> for emoji? So far I have:
> 
> X => Noto Color Emoji (+EmojiOne?)
> NS => Apple Color Emoji
> Windows => ?

Windows has Segoe UI Emoji as its font for Emoji.

However, we only put free fonts in our fontsets, so I think only Noto
Color Emoji qualifies.  Users of macOS and MS-Windows can either
install that font or rely on the OS built-in capabilities to find the
required font.