[MPEG-OTSPEC] Issues from CSS: Will they be covered by the text shaping WG?

[John Hudson]

On 13082020 6:57 pm, fantasai wrote:
> Basically, from CSS's perspective, features can be
>   * mandatory (never turned off because required for correct shaping)
>   * optional, on by default
>   * optional, off by default
> OpenType mentions on vs off by default, but is less clear about 
> mandatory vs optional. 

Over the years I've had periodic discussions with Microsoft about doing 
a thorough review and reconfiguration of the OTL feature registry, but 
there’s never been an opportune moment in terms of either my time or 
their budget. I'm hoping that this is something the new group could 
undertake.

Reconfiguration would involve providing some additional standard data 
for each feature, one of which would be ‘default state’. I took a run at 
that data a few years ago in the tables in
http://tiro.com/John/Enabling_Typography_(OTL).pdf
using a simple notation:

     1/0 = on by default and cannot be turned off
     1/1 = on by default, but can be turned off
     0/1 = off by default but can be turned on

A couple of additional features have been registered since then, and the 
data isn’t official, but it was reviewed by various MS and Adobe people 
at the time. The groupings and ordering turned out to be pretty close to 
what Andrew Glass defined for the Universal Shaping Engine.

J.

-- 

John Hudson
Tiro Typeworks Ltd    www.tiro.com
Salish Sea, BC        tiro at tiro.com

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