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Re: CSS21 9.10 Text direction (revised slightly)

From: Tex Texin <tex@i18nguy.com>
Date: Sun, 19 Oct 2003 18:09:48 -0400
Message-ID: <3F930BAC.3EBE051D@i18nguy.com>
To: W3C Style <www-style@w3.org>, W3c I18n Group <w3c-i18n-ig@w3.org>

Hmm. I guess the comment on table layout isn't pertinent to the Unicode bidi
algorithm so ignore that.

But a further comment on examining the document for rtl characters: Since
content can come from the CSS style sheet, and it might contain rtl characters,
"the document" needs to be thought of as more than the source document, since
CSS content also needs to be considered. It is possible I use :before and
:after to introduce some RTL characters or perhaps generate a list using Hebrew
or Arabic (Hindi) numbers.

tex

Tex Texin wrote:
> 
> http://www.w3.org/TR/CSS21/visuren.html#direction
> 
> Says:
> 
> "If a document contains right-to-left characters, and if the user agent
> displays these characters in right-to-left order, the user agent must apply the
> bidirectional algorithm."
> 
> I wonder if this requirement statement is precise and comprehensive.
> 
> 1) Perhaps it should state what the bidi algorithm should be applied to? The
> whole document? The smallest block containing all the right-to-left characters?
> Only blocks containing rtl characters?
> 
> I can imagine implementors trying to reduce the use of the bidi algorithm to
> maximize performance, and perhaps not identifying the impact correctly. There
> is an impact due to neutral characters being reordered, so just identifying
> right-to-left characters is not sufficient.
> 
> 2) Since direction can be set in CSS and direction has some impact on the
> document even if there are no RTL characters, perhaps the requirement should
> reference this possibility. For example table layout would be affected.
> 
> So the requirement should perhaps read:
> 
> "If the user agent displays right-to-left characters in right-to-left order,
> and
> if a document contains right-to-left characters or has any right-to-left
> direction settings (in Markup or via CSS),
> the user agent must apply the bidirectional algorithm to the document."
> 
> (I know this needs tweaking but thought I would throw it out to clarify my
> comments.)
> 
> tex
> 
> --
> -------------------------------------------------------------
> Tex Texin   cell: +1 781 789 1898   mailto:Tex@XenCraft.com
> Xen Master                          http://www.i18nGuy.com
> 
> XenCraft                            http://www.XenCraft.com
> Making e-Business Work Around the World
> -------------------------------------------------------------

-- 
-------------------------------------------------------------
Tex Texin   cell: +1 781 789 1898   mailto:Tex@XenCraft.com
Xen Master                          http://www.i18nGuy.com
                         
XenCraft		            http://www.XenCraft.com
Making e-Business Work Around the World
-------------------------------------------------------------
Received on Sunday, 19 October 2003 18:14:27 GMT

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