[mpeg-OTspec] Two proposals: 1) Register a new OpenType feature (vrtr) & 2) Update a registered OpenType feature description (vert)

[Ken Lunde]

John,

Apologies for the delay in replying.

The "subset" aspect of 'vert' with respect to 'vrt2' is best described by stating that current implementations of 'vrt2' include (or inherit) all of the substitutions in 'vert', and provide additional substitutions that are pre-rotated forms of any glyph that is not full-width, which at present time means proportional-, half, third-, and quarter-width glyphs.

With regard to 'vrt2', I agree that its description should be modified, mainly to specify the legacy nature of its continued use. First of all, the description should nuke the "overrides the 'vert' feature," because that goes against any hope in preferring UTR50-based implementations over vrt2-based implementations.

With regard to the tag of the new GSUB feature, which was proposed as 'vrtr', 'vrot' is another reasonable candidate. As far as I am aware, Adobe does not yet have any implementations that use it. While I prefer the 'vrtr' tag, I would not object if the consensus is to use the 'vrot' tag instead.

Lastly, it was good to see you at IUC37 this week.

Regards...

-- Ken

On Oct 17, 2013, at 12:11 PM, John Hudson <john at tiro.ca> wrote:

> In the current spec, the <vert> feature is described as
> 
> 	...a subset of the vrt2 feature; vrt2 is preferred.
> 
> And the <vrt2> feature description notes
> 
> 	Overrides the vert (Vertical Writing) feature,
> 	which is a subset of this one.
> 
> Aside from the fact that I'm unclear what 'subset' means in this 
> context, I wonder whether Ken's proposed revisions to the <vert> feature 
> description -- which seem fine and sensible in themselves -- might also 
> imply revisions to the <vrt2> feature description, also with regard to 
> the new <vrtr>?
> 
> 
> Also, I think <vrot> is a better mnemonic tag for the new rotation 
> feature, but that's cosmetic and perhaps Adobe have already implemented 
> as <vrtr>.
> 
> 
> J.
> 
> 
> -- 
> 
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> Gulf Islands, BC      tiro at tiro.com
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