bug#64420: string-width of … is 2 in CJK environments

[Eli Zaretskii]

> From: Yuan Fu <casouri@gmail.com>
> Date: Fri, 11 Aug 2023 11:07:26 -0700
> Cc: dmitry@gutov.dev,
>  itaemu@gmail.com,
>  64420@debbugs.gnu.org
> 
> On terminal, I saw an interesting option, “Ambiguous characters are 
> double-width” (terminal-setting.png), which is the same as 
> cjk-ambiguous-chars-are-wide. If I turn it on all the ambiguous characters 
> are indeed displayed in double-width. (terminal-narrow.png, terminal-wide.png)

And in that case, you need to set cjk-ambiguous-chars-are-wide non-nil
to have Emacs display those characters correctly?  Or does that option
have no effect on the correctness of the |Emacs display on that
terminal?

> On GUI display, the later-half of the ambiguous characters are definitely 
> wider than one char, but they aren’t quite 2 chars wide either. But I guess 
> it doesn’t matter too much since one should use pixel size on GUI anyway.

Is the actual width closer to 1 or to 2?

Thanks.