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RE: [css-fonts-3] i18n-ISSUE-296: Usable characters in unicode-range

From: Phillips, Addison <addison@lab126.com>
Date: Fri, 13 Sep 2013 04:11:12 +0000
To: John Daggett <jdaggett@mozilla.com>, Richard Ishida <ishida@w3.org>
CC: W3C Style <www-style@w3.org>, www International <www-international@w3.org>
Message-ID: <7C0AF84C6D560544A17DDDEB68A9DFB5170E3306@ex10-mbx-36006.ant.amazon.com>
John Daggett wrote:
> 
> > 4.5. Character range: the unicode-range descriptor
> > http://www.w3.org/TR/2013/WD-css-fonts-3-20130711/#unicode-range-desc

> >
> > "Valid Unicode codepoint values vary between 0 and 10FFFF inclusive."
> > Do we need to say something about characters that cannot be used, such
> > as surrogate codepoints?
> >
> > Perhaps what is meant is that the codepoint values cannot be higher
> > than 10FFFF or lower than 0. In this case, perhaps the spec should say
> > that the codepoint space (range) is between 0 and 10FFFF, rather than
> > give the impression that all values in that space are acceptable.
> 
> Hmm, unicode ranges are used to indicate *possible* coverage ranges for fonts.
> The actual range used in font matching is ultimately determined by the
> intersection of the unicode-range descriptor value with the actual character
> map of the font.  There's no attempt to separate actual "valid" Unicode values
> from ones that are invalid.  I don't think I see a need here to discuss the nitty
> gritty of surrogate handling.
> 

I don't think that's really the point though. We read this section in the WG call this morning. The text you have got is a little sloppy with the word "valid". The range of Unicode code points is, indeed, "valid" between 0 and 0x10FFFF, but not all of those code points are "valid" characters. We don't really want you to discuss the nitty gritty of surrogates and non-character code points. But the idea is that maybe you should say instead: "Unicode code points range between 0 and 0x10FFFF inclusive" avoiding the problematic word "valid"

Addison
Received on Friday, 13 September 2013 04:12:16 UTC

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