From: Peter_Constable@sil.org
Date: Thu Jul 24 2003 - 14:05:11 EDT
Philippe Verdy wrote on 07/23/2003 10:19:09 PM:
> However, its canonical decomposition into <COMBINING DIERESIS,
> COMBINING ACUTE ACCENT> who are both of combining class
> 230 (Above), has an impact in renderers: they are supposed to stack
> one above the other, so the ACUTE ACCENT (oxia, tonos) should
> appear *above* the DIERESIS (Dialytika). But usage in Greek (similar
> cases occur with Vietnamese Latin letters with two above diacritics),
> show that they do not stack up, but above diacritics are really
> combined (the tonos accent is written in the middle of the two dots of
> the dialitika).
>
> So this is alredy a case where diacritics can (and should) ligate by
> default, and that a CGJ may be used to remove (?) this ligature of
> accents and instead use the vertical stack.
Not needed, IMO, nor would it be a good idea to use CGJ as a rendering
control. A while ago there was an idea that CGJ could be used as a
rendering control in exactly the opposite way: presence of CGJ would give
the side-by-side stacking needed for Vietnamese and Greek. That idea was
rejected, however. (Besides, the positioning for Greek and for Vietnamese
are not entirely the same.)
> If this is wrong, then
> how do you combine a macron with a dieresis?
*Macron* and diaeresis? How can these combine in any way other than
vertical stacking?
> If correct placement of diacritics must be specified, could we use the
> ideographic description characters to create those combining
> sequences with a more descriptive composition rule?
Yikes! My initial reaction is that I hope we don't go that direction.
- Peter
---------------------------------------------------------------------------
Peter Constable
Non-Roman Script Initiative, SIL International
7500 W. Camp Wisdom Rd., Dallas, TX 75236, USA
Tel: +1 972 708 7485
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