bug#70000: 29.2; Grapheme handling incorrect

[Phillip Susi]

Eli Zaretskii <eliz@gnu.org> writes:

> I understand.  But Emacs needs this information also long after the
> characters were already drawn.  For example, imagine that Emacs

Yes, it would have to learn the width the first time it displays each
grapheme and build a list of known widths to remember for future use.

> In addition, if Emacs had to query the cursor position after each
> written character, its redisplay would be much slower than it is now.

It would only need to query when printing a grapheme cluster, and only
the first time.  After that, it could remeber.