Re: can Context render complex scripts?

[Khaled Hosny <khaledhosny@eglug.org>]

On Sun, Jun 13, 2010 at 02:29:40PM -0500, Michael Saunders wrote:
> > As Khaled mentioned ... are these proper otf fonts or do they rely on
> > specific features in the microsoft engine?
> 
> They all carry the .ttf extender.  Arial Unicode MS is clearly True
> Type.  I've seen some of the free fonts widely described as Open Type,
> but they are all amateur products---maybe they don't comply with the
> standard properly.
> 
> If True Type fonts won't work correctly without an external engine and
> Context can't harness an external engine, then it looks like I will
> just have to wait for a more modern font to come along.

OpenType (just ignore file extension for the moment) is a rather dump
standard in the sense that it requires the engine to have some knowledge
about the writing system at hand. Take Arabic as an example, the engine
need to know about the rules of Arabic shaping, what are letters are
dual joining, what are right joining only etc. and then apply OpenType
features conditionally on those characters, without that knowledge, no
OpenType engine is capable for rendering Arabic, and the same is true for
any other complex script.

On the other hand, there is AAT and Graphite fonts, that are implemented
in a more generic way, where the engine has no particular knowledge about
any writing system and all the rules are embedded into the font. Though
this seems a bit smarter, it makes the task of building a font very
complex and tedious since the rules have to be implemented again and
again in each font, also type designers are not programmers and asking
them to do such complex tasks is impractical, for example you can count
all AAT fonts that produced outside Apple, the makers of the technology,
on one hand, now even Apple is moving to OpenType.

So, what we have here is that ConTeXt has no special knowledge about
Indic scripts, and thus it will not apply the feature properly according
the linguistic rules. So, instead of waiting for a "more modern font to
come along" (which unlikely to happen any time soon, giving how much the
industry have invested into OpenType, and the apparent failure of AAT),
just try to reach more people in the Indic community and come out with a
clear specification and tests that Hans can implement.

Regards,
 Khaled

-- 
 Khaled Hosny
 Arabic localiser and member of Arabeyes.org team
 Free font developer
___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!

maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
webpage  : http://www.pragma-ade.nl / http://tex.aanhet.net
archive  : http://foundry.supelec.fr/projects/contextrev/
wiki     : http://contextgarden.net
___________________________________________________________________________________