bug#48125: 28.0.50; Display garbled by emoji variation sequence

[Eli Zaretskii]

> From: Filipp Gunbin <fgunbin@fastmail.fm>
> Cc: 48125@debbugs.gnu.org
> Date: Tue, 04 May 2021 19:20:27 +0300
> 
> > OK in what sense?  On TTY frames layout and rendering are left to the
> > terminal emulator; if it can handle this situation, Emacs won't care.
> 
> The effect of different widths is, of course, different number of chars
> per line (easily seen in Terminal with emoji or Asian scripts).  Does
> Emacs make assumptions about number of columns per line?

It does, but the number of columns doesn't change, only the width
changes.  Right?

What Emacs expects is that the terminal emulator will space characters
according to the width in columns (either 1 or 2) of each character,
as defined in the Unicode Character database.  You can see what Emacs
thinks about the width of each character by using 'char-width'.
AFAIR, all emoji should have width of 2, is that right?