[MPEG-OTSPEC] VARC issues with the published OFF 5th ed

[Dave Crossland]

Smaller and faster the better imo :)

On Sun, Oct 4, 2026, 8:03 AM Vladimir Levantovsky <
vladimir.levantovsky at gmail.com> wrote:

> Input contribution deadlines are October 12 for registration and October
> 13 for submission.
>
> Thank you,
> Vlad
>
> On Oct 3, 2026, at 5:28 PM, Behdad Esfahbod <behdad at behdad.org> wrote:
>
> 
> Thanks Vlad,
>
> What would be the deadline to submit contribution for the October 19-24
> meeting?
>
> I'm hoping that we can get away with a corrigendum.
>
> behdad
> http://behdad.org/
>
>
> On Sat, Oct 3, 2026 at 10:54 AM Vladimir Levantovsky <
> vladimir.levantovsky at gmail.com> wrote:
>
>> Hi Behdad, all,
>>
>> To start the process of making corrections, it would be ideal if you
>> prepare an input contribution for the upcoming SC29/WG3 meeting that will
>> be held on October 19-24.
>>
>> Depending on the amount and the severity of proposed changes, we can
>> decide whether issuing a corrigendum would be a suitable option, or if it
>> requires an amendment. A corrigendum would be quicker path forward; an
>> amendment would have to follow the typical path of WD - CD/PDAM - FDAM
>> (with ballots issued at every stage), before it is finalized and published.
>>
>> Thank you,
>> Vladimir
>>
>> On Oct 2, 2026, at 9:18 PM, Dave Crossland <dcrossland at google.com> wrote:
>>
>> 
>> Thanks for flagging these, Behdad. Glad to see you're cross-checking the
>> implementations already.
>>
>> Vlad, sounds like this is enough to Kickoff a 1st amendment :) if so,
>> what would you for cast as an overall end to end timeline?
>>
>>
>> --
>> [image: GDP logo]
>>
>>
>> Dave Crossland
>>
>> Font Expert
>>
>> Google Design Platform
>>
>>
>>
>> On Fri, Oct 2, 2026, 3:30 PM Behdad Esfahbod <behdad at behdad.org> wrote:
>>
>>> Hello everyone,
>>>
>>> Thank you, Vlad, and everyone else who worked in the past four years to
>>> get the boring-expansion proposals into the ISO OFF 5th ed.
>>>
>>> Since the PDF became freely available on Monday, I've been busy
>>> cross-checking my implementations against the spec. Generally things are
>>> holding up well, but unfortunately I discovered three issues in the VARC
>>> table that I recommend fixing in the spec. Details and recommendation in
>>> the github issues:
>>>
>>>
>>> *1. VARC ConditionList: restore omitted uint32 conditionCount*
>>> This one is was lost in translation from my working design to the ISO
>>> proposal. It's currently impossible to implement the ISO spec, because it
>>> defines an array without defining its length anywhere:
>>>
>>>   https://github.com/harfbuzz/boring-expansion-spec/issues/176
>>>
>>> *2. VARC: make SparseVariationRegion axis offsets table-relative and
>>> correct its designation*
>>>
>>> This was was a mistake from the review modifications of the table format
>>> to promote a struct to a table, but this was not done properly. Offsets
>>> should be relative to the beginning of their table, not the grandparent
>>> table as currently speced.
>>>
>>>   https://github.com/harfbuzz/boring-expansion-spec/issues/177
>>>
>>> *3. VARC: Remove the exception to ordinary LSB/origin alignment for
>>> components*
>>>
>>> This is a design leftover from when I had encoded the
>>> variable-composites in the `glyf` table. In that design, the recommendation
>>> made sense. In a separate `VARC` table, it doesn't, and hinders
>>> implementation. This change wouldn't affect properly-made fonts (lsb=xMin).
>>>
>>>   https://github.com/harfbuzz/boring-expansion-spec/issues/173
>>>
>>>
>>> That's it for now. I will be spending a lot more time with the spec, but
>>> I don't expect other major issues to arise.
>>>
>>> Thanks,
>>> behdad
>>> http://behdad.org/
>>>
>>
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