Re: [css-fonts] font-language-override

On 01/06/16 01:35, Levantovsky, Vladimir wrote:

> I am not sure why font-language-override is really needed, can’t a 
> developer simply define a span with another language tag [the one 
> which behavior one wants to mimic]? Won’t the end result be the same ?

The point of the font-language-override is to enable an author to 
specify an OTL language system as supported in a font, in order to 
affect a particular typographic display, while retaining accurate 
document language tagging. Your suggestion fails in the latter regard, 
requiring inaccurate document language tagging in order to affect a 
particular display.

The example I give is a document in Macedonian language, displayed with 
a webfont that provides Cyrillic variant letters desirable for 
Macedonian but only associated in that font with a Serbian OTL language 
system tag. Instead of hacking the font to add a Macedonian language 
system feature tree, which is both technically non-trivial and may not 
be permitted under font license, an author can use 
font-language-override to activate the Serbian OTL language system 
display behaviour for the Macedonian document text.

> Depending on complex mappings from @lang to OpenType lang is a lot of 
> work, currently being done for you by font designers. This is a 
> duplication of effort and a maintenance burden; just support 
> font-language-override. It is there for a reason.
>
> OpenType maintains its own language tag system where the mappings in 
> most cases are 1:1 and in some cases are n:1, but I wouldn’t consider 
> it a complex mapping – as far as user is concerned, there is always a 
> straightforward mapping from a content language tag to the OT language 
> tag. Changing the content language tag, e.g. by defining a span with a 
> different tag, should do the trick.
>

I'm going to be pedantic and insist that we use the full correct term 
'language system' for the OTL tags — even though it is itself a 
misleading misnomer —, because it is important to note that these are 
*not* language tags, but a means of activating particular typographic 
display, which may or may not map to document language tagging; indeed, 
it might not map to a language at all, as in the case of OTL language 
system tags for IPA and Americanist phonetic transcription.

JH


-- 

John Hudson
Tiro Typeworks Ltd    www.tiro.com
Salish Sea, BC        [email protected]

Getting Spiekermann to not like Helvetica is like training
a cat to stay out of water. But I'm impressed that people
know who to ask when they want to ask someone to not like
Helvetica. That's progress. -- David Berlow