Re: Open-Type Support (was: Greek Prosgegrammeni)

From: John H. Jenkins (jenkins@apple.com)
Date: Wed Nov 22 2000 - 14:25:26 EST


At 10:31 AM -0800 11/22/00, Peter_Constable@sil.org wrote:
>Let me add a little to what Marco has written:
>
>OT implementations are being done for Mac and Unix/Linux. On the Mac side,
>Apple reps have made statements that suggest that they would incorporate
>system-level support for the aspects of complex rendering that OT itself
>doesn't provide (i.e. they'd write something comparable to Uniscribe). On
>Unix/Linux, I'm not sure what is being done about providing the support
>that OT itself lacks.
>

That's perhaps too strong a statement. Basically, we are
investigating the addition of system-level OT support. It's clearly
desirable, but whether or not it will happen is still an open
question.

>
> >- AAT/ATSUI (see in http:/www.apple.com).
>>Most of the "intelligence" is in the font itself, which also includes a
>>state machine to operate substitution. The behavior of the smart fonts may
>>be influenced by external user settings.
>
>Essentially, all of the intelligence is in the font. (There is an external
>engine that runs the state tables in the font, but that's a generic engine
>- all the behaviour is embodied in the state tables in the font). Thus,
>complex script rendering for polytonic Greek (for example) is available if
>a system has an AAT font that implements support for that script. In order
>to take advantage of that capability, however, an application must be
>written to use the ATSUI text drawing interfaces rather than the older
>QuickDraw interfaces. Developers have been slow on the uptake, but Apple
>has been working hard to make it easier for developers to support these
>interfaces.
>

On the Mac OS X side, the Cocoa set of interfaces derived from NeXT
also make use of AAT, although such support is currently limited.
Nonetheless, fonts with AAT features turned on by default will pretty
much have those features appear in Cocoa apps as well as ATSUI/MLTE
apps.

-- 
=====
John H. Jenkins
jenkins@apple.com
jenkins@mac.com
http://www.blueneptune.com/~tseng



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