[MPEG-OTSPEC] CSS WG liaison to SC29 on Open Font Format (from Feb. 2020)

[Simon Cozens]

On 15/03/2024 15:07, John Hudson via mpeg-otspec wrote:
> I presume the idea is that all the intelligence for substitutions and 
> insertions resides in the feature variations GSUB for the JSTF axis, 
> including contextually controlled kashida insertion logic, and the 
> justification engine would only be responsible for figuring out how much 
> to contract or expand lines to fit the measure?

Exactly, yes. I'm only familiar with it in concept from the font side of 
things; you'll have to discuss with Behdad how he implemented it on the 
Harfbuzz side.

> As an axis that is intended to interact with common software 
> functionality, this looks to me like something that might be a clear 
> candidate for formal registration in the spec alongside weight, width, etc.

Well, yes; but the premise of this discussion was "variable fonts can do 
everything that the JSTF table promised, so I don't think we need 
updates to the JSTF table any more."

S