[luatex] luatex's (mis-)handling of Unicode Devanagari vowel signs and ligatures

Khaled Hosny khaledhosny at eglug.org
Thu Feb 17 12:13:47 CET 2011

On Thu, Feb 17, 2011 at 07:32:19AM +0100, Taco Hoekwater wrote:
> On 02/16/11 16:15, Khaled Hosny wrote:
> > There is currently no support for Indic scripts in our OpenType layout
> > engine, simply because no one asked for it.
> > 
> > Since Hans don't read any of these languages, he will need help from
> > someone who can. So if you are interested in digging into this finding
> > relivant specs, fonts, reference renderings and so (be warned, Indic
> > support is OpenType is a big mess with basically two incompatible
> > standards one deprecated but there are many fonts out there using it),
> > then contact Hans and I think he would be interested in such help.
> The problem with complex scripts is that they sometimes need more
> support that just turning on opentype features. For example,
> in Arabic script, there is a the need to analyze the relative
> location of the characters (initial, medial, final, isolated).
> This process is not actually encoded in the font itself, it has
> to be done by the engine based on whether or not the engine
> believes it is in Arabic mode (yes, that it is indeed a little
> fuzzy).

Not that fuzzy, you either set the script manually (which what we
already do) or the engine implements Unicode script classification
algorithm (pretty simple, unlike BiDi) which e.g. Pango does.


 Khaled Hosny

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