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Re: [css3-fonts] Language-specific display and 'locl' feature (was RE: [css3-writing-modes] The original issues of font-dependent glyph orientation

From: John Daggett <jdaggett@mozilla.com>
Date: Sun, 2 Oct 2011 17:57:00 -0700 (PDT)
To: Koji Ishii <kojiishi@gluesoft.co.jp>
Cc: Taro Yamamoto <tyamamot@adobe.com>, www-style@w3.org, Jonathan Kew <jonathan@jfkew.plus.com>
Message-ID: <789440076.3135.1317603420305.JavaMail.root@zimbra1.shared.sjc1.mozilla.com>
Koji Ishii wrote:

> Maybe I'm asking the same question again, sorry in that case, but so
> if a font has 'locl' with appropriate script/language system tables,
> is it automatically applied when 'lang' attribute is set?

Jonathan actually answered this fairly clearly but maybe it would help
if I simply restate what he said:

1. Per CSS3 Fonts, the language of an element is mapped to an OpenType
language. [1]

2. Per the OpenType spec, the 'locl' feature is on by default. [2]

3. The language/script mechanism in OpenType allows for language or
script specific versions of any feature, so to control the default
forms of glyphs a font designer could use a language-specific
definition of the 'locl' feature.

Default features are somewhat mushily defined in the OpenType spec but
implemenations are generally consistent about the core set of default
features, including in this case 'locl'.

Regards,

John

[1] language used to determine OpenType language
http://dev.w3.org/csswg/css3-fonts/#language-specific-support

[2] locl feature
http://www.microsoft.com/typography/otspec/features_ko.htm#locl
Received on Monday, 3 October 2011 00:57:39 GMT

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