Re: master 94380420e2: Support Noto Emoji font as fallback

[Robert Pluim]

>>>>> On Fri, 23 Sep 2022 15:54:45 +0300, Eli Zaretskii <eliz@gnu.org> said:

    Eli> I think we should limit specifying particular fonts in our fontset
    Eli> setup only to those cases where either the "normal" search for
    Eli> suitable fonts is likely to fail, or if some font is really superior
    Eli> to the alternatives.

Looking at this some more, Iʼm getting unexpected behaviour for the
'bamum' script (Iʼm basing this off the fallback settings in
fontset.el for 'simple scripts').

emacs -Q
C-x 8 RET 16900 -> hex box
eval (set-fontset-font t 'bamum
       (font-spec :registry "iso10646-1" :script 'bamum) nil 'prepend)
       -> hex box
eval (set-fontset-font t 'bamum
        (font-spec  :script 'bamum) nil 'prepend)
        -> it finds a glyph using the following font
ftcrhb:-Goss-Kurinto Seri-regular-normal-normal-*-19-*-*-*-*-0-iso10646-1 
(#x2A66)

which is a locally installed font. If I move that out of the way it
finds the following system font with the second `set-fontset-font' only.

    ftcrhb:-GOOG-Noto Sans 
Bamum-regular-normal-normal-*-15-*-*-*-*-0-iso10646-1 (#x151)

so the registry spec is preventing emacs from finding the font? (Iʼm
failing once again to get fc-match to tell me what scripts are
supported by a particular font)

Robert
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