[mpeg-OTspec] Updated 4th edition working draft available for review

[John Hudson]

Peter, I'm a bit concerned that this wording makes some assumptions about how implementations use the DFLT script tag, without those implementations being specified anywhere. [Well, nothing new in that: this is true of OpenType Layout in general.] So, for example, I've seen DFLT used by Adobe to process script=common characters such as the Indic danda and double danda from the Unicode Devanagari block, which are also used by other Indian scripts. If one wanted to make a pan-Indic font with script-specific forms of danda, the only way to do so within that implementation would be via language system under the DFLT script tag. Of course, the case can be made that such an implementation is wrong, but sans an implementation spec, I wonder about the wisdom of specifying constraints in the format spec.

JH


Sent from my iPad

> On Mar 31, 2017, at 5:48 AM, Peter Constable petercon at microsoft.com [mpeg-OTspec] <mpeg-OTspec-noreply at yahoogroups.com> wrote:
> 
> A font is permitted to have a 'DFLT' script table with non-default language system tables, and an application
> 
>         may use features associated with one of these if the the 'DFLT' script table is applicable (no script table
> 
>         is present for the specific script), and if one of the particular language systems is specified. Applications
> 
>         are not required to support use of a non-default language system table that is associated with 'DFLT' script,
> 
>         however, and fonts should not depend on this configuration being supported.
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