[MPEG-OTSPEC] Rules for cubic bits in glyf flags include undefined behaviour for some configurations

[Skef Iterum]

The existing proposal prohibits an implied/interpolated point between a 
quadratic off-curve point and a cubic off-curve point:

    Either all the off-curve points between any two on-curve points
    (with wrap-around) have the CUBIC flag clear, or they all have the
    CUBIC flag set.

So the question of whether to allow and what to do about implied cubic 
on-curve points should be completely separable from the treatment of 
implied quadratic on-curve points. I don't think anyone has proposed (or 
otherwise has in mind) removing implied quadratic on-curve points from 
the specification or altering how they're processed.

Skef

On 10/2/23 14:33, Hin-Tak Leung wrote:
> I'd just like to raise two points:
>
> - while the rendering system cannot be specified to cope with 
> arbitrary amount or type of font brokenness, the problem with 
> disallowing implied on-curve cubic points, or mandating that off-curve 
> cubic points must be in pairs, is that off-curve points (and implied 
> on-curve points) are very frequently used and beneficial in 
> quadratics. You shouldn't take away capability that is not only 
> allowed, but encouraged.
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.aau.at/pipermail/mpeg-otspec/attachments/20231002/0186bd13/attachment-0001.html>