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

[John Hudson]

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?

For the benefit of the engine, we would need to define what should 
happen if the JSTF axis maxes out and the measure still has not been 
filled—probably allowing further expansion of inter-word spacing as per 
most existing justification engines.

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.

JH


On 2024-03-15 4:29 am, Simon Cozens via mpeg-otspec wrote:
> On 14/03/2024 15:02, John Hudson via mpeg-otspec wrote:
>> ‘JSTF=0 - JSTF=1000’ implies that justification always means 
>> expanding-to-fill. Conceptually, the model could handle contraction 
>> also, I think. Has this been considered in the implementation?
>
> Sure, starting the JSTF axis at zero was just an example to how 
> different things could be done along different expansion values. It 
> works mutatis mutandis the other way around: if you want a font that 
> runs JSTF=-1000 to JSTF=1000, just arrange for the glyphs to contract 
> or switch to condensed shapes at appropriate points along the negative 
> part of the axis.
>
> S
>
> _______________________________________________
> mpeg-otspec mailing list
> mpeg-otspec at lists.aau.at
> https://lists.aau.at/mailman/listinfo/mpeg-otspec

-- 

John Hudson
Tiro Typeworks Ltd    www.tiro.com

Tiro Typeworks is physically located on islands
in the Salish Sea, on the traditional territory
of the Snuneymuxw and Penelakut First Nations.

__________

EMAIL HOUR
In the interests of productivity, I am only dealing
with email towards the end of the day, typically
between 4PM and 5PM. If you need to contact me more
urgently, please use other means.