[HarfBuzz] Ligatures and color changes

[Jonathan Kew]

On 20/2/13 12:24, Lóránt Pintér wrote:
> I'm trying this with a font that has the kerning data in the "kern"
> table as well as in the "GPOS" table. (Is that possible?)
>
> Can you show me a font that this feature works with?
>

I thought we'd seen it work last week, but now it doesn't seem to. :( 
Behdad, did we miss something here? It seems to me like the skippy_iter 
in PairPosFormat1::apply doesn't know what it's looking for...

JK

> --
>
> *Lóránt Pintér*
>
> Developer at Prezi <http://prezi.com>
>
> On Wednesday, February 20, 2013 at 10:26 AM, Jonathan Kew wrote:
>
>> On 19/2/13 23:35, Lóránt Pintér wrote:
>>> Using ZWNJ would be a great way of fixing it. And indeed it splits the
>>> ligature all right, but it also destroys the kerning. Here's a little
>>> test I did with HarfBuzz @ e0486fc1affd3796fb8f664e2e7fc208f1d2106c:
>>> (the font has an "fi" ligature, and has some kerning between "F" and ",")
>>>
>>> Splitting the ligature with the ZWNJ works:
>>>
>>> Shaped "fif\u200Ci" with features: [ ]
>>> Glyph: #682, x_advance: 652
>>> Glyph: #71, x_advance: 380
>>> Glyph: #3, x_advance: 0
>>> Glyph: #74, x_advance: 292
>>>
>>> Kerning across the ZWNJ does not:
>>>
>>> Shaped "F,F\u200C," with features: [ ]
>>> Glyph: #39, x_advance: 483
>>> Glyph: #13, x_advance: 242
>>> Glyph: #39, x_advance: 563
>>> Glyph: #3, x_advance: 0
>>> Glyph: #13, x_advance: 242
>>>
>>> Is it possible that doing this will be supported later in HarfBuzz?
>>
>> Hmm - is that font using a legacy 'kern' table, or a GPOS 'kern'
>> feature? For the former, I can understand that kerning would break, as
>> it's a naïve glyph-pair lookup, but for the latter, I thought we should
>> now ignore the ZWNJ.
>>
>> JK
>