Re: [css3-writing-modes] referring to Unicode

On 05/01/2011 06:57 PM, John Daggett wrote:
>> From the section entitled "Orienting Text: the ‘text-orientation’ property":
> http://www.w3.org/TR/css3-writing-modes/#text-orientation
>
>> The orientation of characters belonging to the Common, Inherited, and
>> Unknown script categories may be UA- or font-dependent in vertical
>> typographic modes. The Unicode East Asian Width property [UAX11] can
>> be used to distinguish whether a character is typically be set upright
>> or sideways in ‘vertical-right’: characters classified as fullwidth
>> (F) or wide (W) are typically set upright (using vertical font
>> settings), whereas characters classified as neutral (N), narrow (Na)
>> or halfwidth (H) are typically set sideways (using horizontal font
>> settings).
>
> Since CSS specs are both explaining behavior and defining
> implementation, referring to a Unicode technical note is fine for
> referring to a deeper explanation of a concept but is *not* sufficient
> for defining implementation behavior. Implementation behavior should
> be defined in terms of the Unicode database [1] instead, by
> referencing specific data fields in specific files, e.g. the
> EastAsianWidth.txt file in your example here.  The technical notes
> often don't always cover all the subtleties implicit in using this
> data and that's something any definition of implementation behavior
> needs to cover explicitly, otherwise you end up with untestable muddle.

The EastAsianWidth.txt file is referenced from UAX11. UAX11 gives
the explanation of what it means, how to use it, etc. So I think
that referring to UAX11 is the correct thing to do here. I'll let
Addison correct me if I'm wrong.

I really don't think it's at all ambiguous what the spec means by
"do this with characters classified as fullwidth (F), see UAX11".
You think it's ambiguous?

~fantasai

Received on Tuesday, 3 May 2011 20:24:37 UTC