[HarfBuzz] Indic Test Suite :: "Indie"

Ed Trager ed.trager at gmail.com
Wed Aug 26 14:03:00 PDT 2009

Hi, Adam

On Wed, Aug 26, 2009 at 2:31 PM, Adam Twardoch<list.adam at twardoch.com> wrote:
> Ed Trager wrote:
>> (Recall that Pango will use Uniscribe
>> on Windows, ATSUI/AAT on Mac, so all bases will be covered).
> But isn't it the problem that ATSUI/AAT has not OpenType Layout support
> for Indic? The old ATSUI framework does not support OpenType Layout
> shaping for any complex scripts. The new CoreText framework introduced
> in Mac OS X 10.5 has some rudimentary Arabic suport based on OpenType
> Layout, but both frameworks do Indic shaping solely through AAT, and as
> we all know, there is perhaps a handful of Indic AAT fonts.

Actually, I don't that much about the OS X rendering pipeline, so I
guess I should have said only "AAT".

> It would be tremendously helpful if an Indic test suite (or even more
> generally, an OpenType Layout test suite if you chose to build one)
> allowed the user to choose between the system native layout engine, the
> HarfBuzz/Pango layout engine and the ICU Layout engine.
> There is an interesting OpenType Layout testing app written by Tal
> Leming called FeatureProof:
> http://code.typesupply.com/wiki/FeatureProof
> The app is written in Python for Mac OS X (using the PyObjC bridge) and
> uses an OpenType Layout engine written purely by Tal called Compositor:
> http://code.typesupply.com/wiki/Compositor
> Unfortunately, Compositor has many limitations, the major one is that it
> does not support any complex script shaping at all (just the basic
> GSUB/GPOS calls). However, I think it has some interesting UI concepts,
> and an interesting way to implement test cases.

I'll definitely take a look to get ideas regarding test cases etc.

Best - Ed

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