Re: Compositions and bidi display

[Kenichi Handa <handa@m17n.org>]

In article <83mxwoxo1t.fsf@gnu.org>, Eli Zaretskii <eliz@gnu.org> writes:

> > Provided that uppercase letters denote Hebrew consonants,
> > lowercase denotes Hebrew diacriticals, a buffer has the
> > character sequence "AaBbCc", CHARPOS is the position of 'c',
> > ENDPOS is the position of 'A'.
> > [...]
> > To do all of them, perhaps all I need is to know the way to
> > find the correct ENDPOS.  Please tell me how to do that.

> What is the definition of ENDPOS?  If that's the beginning of the
> composition sequence, that's the same question I asked, for which I
> don't know the answer.  If that's the other end of the R2L run of
> characters,

Yes, that one.

> you need to iterate with bidi_get_next_char_visually until
> some condition (which I cannot yet formulate) is
> satisfied.  But note that this is tricky, because the bidi
> iteration changes direction and jumps at will.

The condition should be "until it reaches a character that
should never be composed with the currently looking
character".  We may be able to simplify that condition to
"until it reaches a character in the different bidi level
(or chunk)".

---
Kenichi Handa
handa@m17n.org