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Re: Unicode controls vs markup for text direction

From: Martin Duerst <duerst@it.aoyama.ac.jp>
Date: Sat, 23 Feb 2008 15:22:06 +0900
Message-Id: <>
To: cfynn@gmx.net, "'WWW International'" <www-international@w3.org>
Cc: Richard Ishida <ishida@w3.org>, "'Tex Texin'" <tex@yahoo-inc.com>

At 21:20 08/02/22, Christopher Fynn wrote:
>In the scenario's you describe why do we even need either mark-up or Unicode bidi control characters in the first place?
> >
> >     <div lang="ar"><img/> TXET CIBARA</div>
>Shouldn't the *default* direction when displaying the glyphs for a string of Arabic or Hebrew characters always be RTL - even when that string is in the middle of other (LTR) text?  The characters themselves have a default directionality and imo there should be no need to indicate directionality
>except where we need to over-ride the default (e.g. to display a Latin string
>as RTL or an Arabic sting as LTR).

Hello Christopher,

Unfortunately, it's not as easy. It works as long as the correct
base directionality (for a whole paragraph) can be figured out
correctly, and as long as there are not more than two levels
(the one from the base directionality plus another one, or
three if there are digits inside RTL) and no complications
with neutrals (parentheses and other syntactic characters).

Other than that, some additional machinery is necessary.

Regards,   Martin.

#-#-#  Martin J. Du"rst, Assoc. Professor, Aoyama Gakuin University
#-#-#  http://www.sw.it.aoyama.ac.jp       mailto:duerst@it.aoyama.ac.jp     
Received on Saturday, 23 February 2008 06:30:45 UTC

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