Re: Better emoji support

[Eli Zaretskii]

> From: Robert Pluim <rpluim@gmail.com>
> Cc: Kévin Le Gouguec <kevin.legouguec@gmail.com>,
>   emacs-devel@gnu.org
> Date: Mon, 20 Sep 2021 10:40:28 +0200
> 
> >>>>> On Mon, 20 Sep 2021 09:53:09 +0300, Eli Zaretskii <eliz@gnu.org> said:
>     >> IIUC Robert's tentative patch[1] gets us closer to The Right Thing, by
>     >> making sure (char-table-range char-script-table C) is "emoji" iff C's
>     >> Emoji_Presentation property is "Yes".
> 
>     Eli> IMO, that's what we want; the emoji sequences should be handled via
>     Eli> composition-function-table, not via the fontset.
> 
> The emoji sequences can be handled by composition, since the relevant
> codepoints will be from the 'emoji' script. But codepoints with
> Emoji_Presentation=No will still be 'symbol' or similar, so how can
> composition-function-table affect their font-selection?

AFAIU, currently this could only be handled if the user has a font
that can display both those Emoji_Presentation=No characters and those
Emoji_Presentation=Yes.  In the future, we could perhaps improve that
by modifying the logic in fontset.c.

I think the presentation of the Emoji appearance for non-Emoji
characters followed by VS-16 is less important than being able to
display sequences of Emoji characters, so we will be doing OK, IMO, if
Emacs 28 only supported the latter.