On Sun, 22 Feb 2009 13:54:51 -0700, Khaled Hosny <khaledho...@eglug.org>
wrote:
http://www.microsoft.com/typography/otfntdev/arabicot/features.htm
:-)
watch the "The standard order for applying Arabic features encoded in
OpenType fonts" ... an earlier mkiv otf handler did this but then we
found out that it violates the otf 'any order possible' rule so now we
do just the order as we encounter it (and even then it took us a while
to figure out where/how to avoid interferences); so ... it's up to the
font designer (or technician)
IIRC, the 'ccmp' should be applied before any other lookup, the rest are
applied as they are ordered in the font, at least this makes sense more.
It is not the order of the features, but the order of the lookups that
really counts here. So, more precisely, the lookups in ccmp should be
defined in the font before all other lookups.
See also
http://www.microsoft.com/typography/otfntdev/arabicot/shaping.htm
http://www.microsoft.com/typography/otfntdev/arabicot/default.htm
now, having init, medi, fina, isol, rlig enabled might be the default,
but for instance arabtype output looks much better when instead of rlig
we use calt/clig etc so, in that case the defaults would bot be the best
choice; again an argument for a database approach
Arabic Typesetting is a quit a special case font, though I believe that
'calt' and 'clig' should be on by default for any font.
That's just it, there are so many exceptional cases it's not trivial to
define a rule. Again, Scheherazade seems appropriate as a place to
start... I will try to find some time in the next month to work on this,
or someone can start and Hans and I can complete the module.
there are even fonts out there that have the right gsub/gpos info but
lack the feature being listed in the script/lang dictionary which is
complicating live even more; maybe we should assume that the renderers
of ms and adobe have some additional built in heuristics of using
specific fonts
Any links to such fonts? Looks interesting.
Hans may be referring to hybrids like Traditional Arabic....
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
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