bug#59606: flags take up so many columns

["Kévin Le Gouguec" <kevin.legouguec@gmail.com>]

Dan Jacobson <jidanni@jidanni.org> writes:

> Why do the flags,
> 🇨🇦; 🇺🇸;👁;🔭;
> seem to take up so many columns?

It would really help us understand the issue if you could give more
details about what you are seeing.  FWIW, I see almost the same results
as Werner, except for "👁", which is not displayed with a color font
(which seems right AFAIU, since your message did not include variation
selector 16, and admin/unidata/emoji-data.txt shows that U+1F441 has
Emoji_Presentation=No).

My understanding (though I don't have a unicode.org reference handy) is
that emoji ought to be presented with "fullwidth", i.e. take twice as
much space as "halfwidth" characters that compose Latin text.

Emacs's string-width function seems to report the "correct" results
here:

(string-width "🇨🇦") ; 2
(string-width "🇺🇸") ; 2
(string-width "👁") ; 1
(string-width "🔭") ; 2

Though FWIW U+1F441 is misaligned on my system, since it is displayed
with Symbola instead of DejaVu Sans Mono (my default font family).

> emacs-version "28.2"