[HarfBuzz] Retrieving optical size info?

[Jonathan Kew]

On 27/11/12 15:37, Khaled Hosny wrote:> On Mon, Nov 26, 2012 at 
02:03:15PM +0200, Behdad Esfahbod wrote:
 >> On 12-11-24 10:58 PM, Khaled Hosny wrote:
 >>> On Sat, Nov 24, 2012 at 01:05:26AM -0500, Behdad Esfahbod wrote:
 >>>> On 12-11-23 07:42 PM, Khaled Hosny wrote:
 >>>>
 >>>>> (Background: I’m almost done with porting XeTeX from ICU 
LayoutEngine to
 >>>>> HarfBuzz, one of the few things remaining is getting optical 
size. The
 >>>>> current code uses some internal LE API and I want to move away 
from this
 >>>>> as possible).
 >>>>
 >>>> Sure, I'll implement it in HarfBuzz for you!
 >>>
 >>> Great!
 >>
 >> Done.  Untested though.  Let me know if it works!
 >
 > Thanks Behdad. It seems that looking for ‘size’ feature under default
 > script does not work, with the attached patch which makes it check all
 > GPOS features, things work fine.
 >
 > Now what remains is handling fonts with broken ‘size’ feature that AFDKO
 > used to make prior 2006, but I’m yet to find documentation for it (Adobe
 > is said to have sent some explanation for a heuristic to handle broken
 > ‘size’ features to OpenType mailing list somewhere in 2006, but I don’t
 > have access to list archives).
 >

I don't seem to have that mail on hand either, but IIRC the existing 
xetex code includes heuristics to handle this, so you could probably 
just use that as a guide.

JK