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Re: [css3-fonts] font-language-override: substantive comments

From: Andrew Cunningham <lang.support@gmail.com>
Date: Wed, 29 May 2013 17:23:04 +1000
Message-ID: <CAGJ7U-X5_DudU8sJn1X7Sh-Vv2KrHxN-U7BHUZG774S6Pg5tJg@mail.gmail.com>
To: John Daggett <jdaggett@mozilla.com>
Cc: www-style <www-style@w3.org>
Hi John,

I am aware of what is meant by 'font-language-override' and in this case i
meant 'font-language-override' although I am aware that lang="ksw" would be
sufficient for Padauk. The problem is that such a system is not extensible.
Browser developers will implement some correspondences that occur to them,
its not possible to implement more than a fraction of the potential
correspondences. Its not practical. And browser developers would not have
access to the data required.

Another problem with assuming and Karen langauge is associated with the KAR
or KSW langauge system is that Karen langauges can also be written with
other scripts.

For Pwo Karen languages in Thailand you will find Thai script
orthographies, and there is also the Leke script which is being proposed
for inclusion in Unicode.

In essence allowing 'font-language-override' to contain a fall-back list
would be more extensible and easier to implement than using the value of
the lang attribute. The lang attribute approach is practical and very
useful, but not extensible and cannot be comprehensive.

A slightly more concrete example:

assuming i have <p lang="pwo"> ...

or any of the other Karen languages (using Myanmar rather than other
scripts) ...

I still need

font-language-override: ksw;  for Padauk and Padauk Book

and

font-language-override: KAR; for Myanmar Text

alternatively for Padauk and Padauk Book, I could use

font-feature-settings: "wtri" 1,"lldt" 1;

to get the same effect, but this will only work on Firefox and only if
graphite support is enabled.

and as of yet I haven't delved into the internals of Myanmar Text to see if
any OT features are available to do something similar.

Andrew


On 29 May 2013 17:03, John Daggett <jdaggett@mozilla.com> wrote:

>
> Hi Andrew,
>
> Thanks for the example.  However, you're mixing up a couple things I think.
>
> > A practical example would be the fonts Myanmar Text, a system font
> > on Windows 8 which has a language system "KAR" for the Karen
> > languages ant Padauk and Padaik Book which has a language system for
> > S'gaw Karen 'ksw'.
> >
> > If a web developer uses the Padauk font and if browsers fall back to
> > Myanmar Text, there needs to be a way of expressing that. Default
> > rendering, ie Burmese/Mon rendering isn't suitable.
>
> Language sensitive features are primarily determined by the content
> language of an element, for HTML the 'lang' tag.  So language-specific
> behavior can be mapped from a ISO-639 lang tag to the data in the font:
>
>   <p lang="ksw">...
>
> I think what you seem to be asking for is language system fallback,
> such that if lang="ksw" wasn't available in the font, you'd use
> lang="kar" instead, rather than the default lang="my".  Am I getting
> this right?
>
> The 'font-language-override' is only meant as an *override* for when
> you want to mimic the features of a different language system.
> Specifying the lang attribute is the intended way for authors to
> indicate the language of their content.
>
> The 'font-language-override' property is also defined in terms of
> *OpenType* language codes, not in terms of ISO 639 lang codes.  Padauk
> is a Graphite font that supports language-specific features via ISO
> 639 lang codes.  It doesn't support OpenType shaping, so
> 'font-language-override' doesn't apply in this case.
>
> Rather than relying on fancy fallback behavior, it would be much better
> to simply use a downloadable font that has the features you need.
>
> Cheers,
>
> John Daggett
>
>


-- 
Andrew Cunningham
Project Manager, Research and Development
(Social and Digital Inclusion)
Public Libraries and Community Engagement
State Library of Victoria
328 Swanston Street
Melbourne VIC 3000
Australia

Ph: +61-3-8664-7430
Mobile: 0459 806 589
Email: acunningham@slv.vic.gov.au
          lang.support@gmail.com

http://www.openroad.net.au/
http://www.mylanguage.gov.au/
http://www.slv.vic.gov.au/
Received on Wednesday, 29 May 2013 07:23:35 UTC

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