[XeTeX] ATSUI/Core Text/etc. Re: "Minimalist" TeX?

[Jjgod Jiang]

Hi Simon,

On Wed, May 23, 2012 at 11:54 AM, Simon Cozens <simon at simon-cozens.org> wrote:
> On 23/05/2012 17:31, Peter Dyballa wrote:
>>
>> Am 23.05.2012 um 03:36 schrieb Simon Cozens:
>> ATSUI is 32-bit only in a 64-bit world
>
> I understand that ATSUI needs to go; that wasn't the question I asked. Why
> replace it with another OSX-only API when others are available?

There are two parts of ATSUI used in XeTeX, one is AAT (Apple Advanced
Typography) support, which is already pretty much deprecated and Mac OS X
10.6 already shipped with OpenType fonts which doesn't require AAT support.
The other part is accessing and query for platform fonts in a native way,
that's the ATS (Apple Type Services) part, which is not deprecated yet.

Core Text provides the replacement for both features. If we decided to
drop AAT support, then we can just keep the ATS part and disable the AAT
part, no Core Text is needed, ICU will still be used for complex text
layout (currently you can switch between AAT and ICU with /AAT and /ICU
suffix in font selection). Or we can leverage the Core Text font manager
API to build a new platform font access implementation that's less likely
to deprecate in the upcoming years. We can also use the Core Text API to
implement AAT support if that's needed after all.

- Jiang