[mpeg-OTspec] MS Proposal: 'svrt' feature

[Behdad Esfahbod]

On 13-01-03 03:30 PM, Michelle Perham wrote:
>  
> 
> I have one last proposal to submit on behalf of Microsoft. This one was also
> put together by Dwayne Robinson. If people feel it’s worthwhile, we’ll need to
> draft the text as it would appear in the spec.
> 
>  
> 
> Summary: Create a new feature tag to account for limitations in the ‘vert’ feature
> 
>  
> 
> Details: The OpenType ‘vert’ feature adjusts the positioning and form of
> numerous upright glyphs in vertical text. However, there is no OpenType
> feature to adjust positioning and form of glyphs of other non-ideographic
> scripts in vertical text, such as Latin turned 90 degrees clockwise. This
> results in poor alignment of certain punctuation. Using ‘vert’ for these
> non-upright characters would be unwise because ‘vert’ substitutes glyph forms
> that are expected to be upright rather than turned, so this can result in
> /doubly/ turned glyphs like brackets and arrows (such as U+2192). Had ‘vert’
> only changed positioning and form, it could have been used for both, where
> higher level layout would have controlled character orientation via a standard
> like UTR 50. However, since ‘vert’ has historically conflated orientation into
> the substitution, I propose the distinct ‘svrt’ GSUB/GPOS tag for such usage -
> credit to Elika Etemad for the idea.

While in general I welcome this proposal, I think there needs to be clear
instructions on how this should interact with 'vert', 'vrt2', as well as
engine-level rotation.  Do you have full feature proposal?

behdad



> Thanks!
> 
>  
> 
> Michelle
> 
> Microsoft Typography Group
> 
> 

-- 
behdad
http://behdad.org/