Subject: bug#39799: 28.0.50; Most emoji sequences don’t render correctly

From: Robert Pluim <[email-masked]>
Date: Fri, 28 Feb 2020 17:24:58 +0100

>>>>> On Fri, 28 Feb 2020 17:44:08 +0200, Eli Zaretskii <[email-masked]> said:

    >> From: Robert Pluim <[email-masked]>
    >> Cc: [email-masked],  [email-masked]
    >> Date: Fri, 28 Feb 2020 16:35:17 +0100
    >> 
    Eli> Readability is desirable because the file will be read by humans.
    >> 
    >> Hmm, maybe. I guess we could process it in elisp to replace the
    >> characters with their names, and adding extra newlines is
    >> trivial. What other kind of changes did you have in mind?

    Eli> Just adding newlines, I think.

OK. Iʼll work on that and the required makefile changes.

One thing this has thrown up that I donʼt understand is this:

Most of the emojis in emoji-sequences.txt can be made to use Noto
Color Emoji, but some canʼt. e.g.

#x24c2 Ⓜ

is stubbornly not being displayed using Noto Color Emoji, even though
that font has a glyph for it, and Iʼve added:

     (set-fontset-font "fontset-default" symbol-subgroup
                      '("Noto Color Emoji" . "iso10646-1") nil
                      'prepend)

just after the similar setting for Symbola in
lisp/international/fontset.el

Itʼs not being displayed with the default font, and setting
use-default-font-for-symbols to nil makes no difference. Itʼs using:

    ftcrhb:-GOOG-Noto Sans CJK JP-normal-normal-normal-*-16-*-*-*-*-0-iso10646-1 (#x3F8)

However, if I
eval

     (set-fontset-font nil #x24c2
                      '("Noto Color Emoji" . "iso10646-1") nil
                      'prepend)

in the frame displaying the character, then it does use Noto Color
Emoji. What am I missing?

Robert