Hi Otared and all,
On Mon, 09 Jun 2008 03:13:06 -0600, Otared Kavian
I just read the thread started by Burak Emir about "Typesetting Arabic today", and tried to typeset the sample sent by Idris Samawi Hamid. One of the Arabic or Persian fonts that I have and LuaTeX can find is Nadeem (working on Mac OS X 10.5.3), but what I get after typesetting is the following attached PDF: all the characters are typeset with their isolated form. However typestting the same text with XeConTeXt or XeTeX gives a nice result.
As Khaled and Wolfgang already intimated, the problem is that Nadeem is not an OpenType font, but rather AAT. XeTeX is mainly Mac-based so it's natural that it supports AAT. It should not be too hard to overload GSUB and GPOS features for this particular font using the fea file overload feature of luatex (not sure if that has been fixed.) I looked at the AAT code, and saved an fea file using FontForge: but the contextual analysis is not there, so I suspect that AAT fonts depend on something like uniscribe for certain basic features. We (=Hans) need to know what that is. But at this stage of development, only pure OpenType fonts will be supported out of the box. For example: Traditional Arabic, which comes with XP, has OpenType tables but depends on Uniscribe instead of OpenType for, eg, making marks exceptions to the contextual analysis. Since the mark exception was not added to the GSUB table, voweled text appears unjoined in Trad. Arabic processed by luaTeX. I suppose we (=Hans) could add some "spell-checking" to the otf analyzer, but that's dangerous and needs some careful thought. Maybe we can come up with various "spell-checking" options that could be turned on and off, so that old-technology (Nadeem is 1998), platform-dependent (like Nadeem and Trad. Ar.) fonts can be used. In any case, we want to stay as platform-independent as possible. So for AAT, we may need to wait at least till someone (maybe one of you?) can come up with a spec so that we can implement a cross-platform solution for AAT. Best wishes Idris -- Professor Idris Samawi Hamid, Editor-in-Chief International Journal of Shi`i Studies Department of Philosophy Colorado State University Fort Collins, CO 80523