[MPEG-OTSPEC] CFF2 errata

[Skef Iterum]

Adobe has discussed these proposals internally and come to some 
short-term conclusions:

  * The vsindex clarifications are strictly editorial and would be
    valuable. A draft of a proposal (/as /a proposal rather than the
    more recent comments format) is attached.
  * The change to the treatment of the VariationStore length field is
    not /strictly/ editorial but is valuable and has a low change of
    causing issues, so it is worth discussing. A proposal for that is
    also attached.
  * We appreciate the issue with the FontMatrix operator and agree it
    might make sense to deprecate it. However, we will need more time
    internally to discuss this and dig up the history of why it was
    retained. In the mean time there is vanishingly small harm in adding
    the operator (when it is required) so we don't feel there is any
    hurry with this.
  * The proposal to allow multiple vsindex operators in a CharString is
    a very significant change that will need further discussion both
    within Adobe and probably outside of it. It will probably require
    bumping the CFF2 major version number (to 3, alas). We will need to
    consider whether to allow the change in the PrivateDict as well, and
    what that means for fallback (what the first proposal clarifies).
    All of this means that this is not the time to be discussing that
    change.

Perhaps we can discuss the two editorial(esque) changes at our next meeting.

Thanks,

Skef Iterum
Adobe, Inc.

On 10/22/24 3:17 PM, Behdad Esfahbod via mpeg-otspec wrote:
> Hi everyone,
>
> CFF2 has a file size advantage over TrueType-flavored variable fonts, 
> specially if one doesn't care about hinting (Android, Apple platforms, 
> etc) but does care about (uncompressed) size.
>
> CFF2 also alleviates some other limitations of variable-fonts built 
> against the gvar table. Unfortunately, it imposes its own limitations. 
> These are among the issues I'm going to raise.
>
> Please see:
>
> https://github.com/harfbuzz/boring-expansion-spec/issues/155
>
> for details of the changes I am proposing. Ideally, Adobe folks choose 
> to turn these ideas into proposals and push it through the OFF 
> standardization / OpenType integration process. Failing that, we might 
> want to go ahead and do it at Google
>
> Thanks,
>
> behdad
> http://behdad.org/
>
> _______________________________________________
> mpeg-otspec mailing list
> mpeg-otspec at lists.aau.at
> https://lists.aau.at/mailman/listinfo/mpeg-otspec
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.aau.at/pipermail/mpeg-otspec/attachments/20241101/79983200/attachment-0001.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: vsindex.pdf
Type: application/pdf
Size: 21997 bytes
Desc: not available
URL: <https://lists.aau.at/pipermail/mpeg-otspec/attachments/20241101/79983200/attachment-0002.pdf>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: vslength.pdf
Type: application/pdf
Size: 23490 bytes
Desc: not available
URL: <https://lists.aau.at/pipermail/mpeg-otspec/attachments/20241101/79983200/attachment-0003.pdf>