[XeTeX] Conjunct consonants in devanagari

Fr. Michael Gilmary FrMichaelGilmary at MaroniteMonks.org
Sun Sep 6 15:29:24 CEST 2009

David Perry wrote:
> Make sure that you are using a native OS X font that contains AAT 
> features.  OS X comes with one or two of these (sorry, I can't tell 
> you the exact names).  You should be able to type the letters (using a 
> Unicode keyboard, of course, such as comes with OS X) and not have to 
> worry about making any manual adjustments; the lookups built into the 
> font are supposed to take care of reordering and reshaping 
> automatically.  If you try to use a font with OT features, such as you 
> would on Windows or Linux, it won't work.  You can use OT fonts with 
> OS X for simple scripts (Latin, Greek, Cyrillic, etc.) but complex 
> scripts such as Arabic and Devanagari require a native AAT font.

Caveat: if you use an AAT font and load it via fontspec, make sure that 
you *don't* use the [Script=Devanagari] option.

The reason is --- as Jonathan said some time ago ---

> The fontspec [Script=....] option presupposes that OpenType "shaping"  
> is to be applied. Al Bayan (and the other Arabic, Indic, etc., fonts  
> that Apple ships) relies on AAT, not OpenType, for shaping behavior.  
> Left to itself, xetex will pick the appropriate rendering technology  
> based on what it finds in the font, but by specifying [Script] in  
> through fontspec you are overriding that, and insisting it use the  
> OpenType route. But Al Bayan doesn't include OpenType tables, so you  
> lose.
> When using AAT fonts, xetex also tries to apply whatever 
> justification  behavior the font provides, which may include kashidas 
> in Arabic  fonts. There's no such support in the OpenType engine at 
> the moment.
> So... two different font technologies. (Note that AAT support is only  
> available on Mac OS X, so users on other platforms should disregard  
> this completely.) 

Hope that helps.

United in adoration of Jesus, 

fr. michael gilmary, mma

Most Holy Trinity Monastery
67 Dugway Road
Petersham, MA 01366-9725

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