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Re: The elements to which unicode-bidi:isolate applies

From: fantasai <fantasai.lists@inkedblade.net>
Date: Sun, 26 Sep 2010 07:26:18 -0700
Message-ID: <4C9F580A.906@inkedblade.net>
To: "Aharon (Vladimir) Lanin" <aharon@google.com>
CC: public-i18n-bidi@w3.org, W3C style mailing list <www-style@w3.org>
On 09/25/2010 05:25 PM, Aharon (Vladimir) Lanin wrote:
> The current definition
> <http://dev.w3.org/csswg/css3-text-layout/#unicode-bidi>
> of unicode-bidi:isolate states:
>
> "For the purposes of the Unicode bidirectional algorithm, the contents
> of the element are considered to be inside a separate, independent
> paragraph, and for the purpose of bidi resolution in its containing
> paragraph (if any), the element itself is treated as if it were an
> Object Replacement Character (U+FFFC). (If the element is broken across
> multiple lines, then each box of the element is treated as an Object
> Replacement Character.)"
>
> I think that it is worthwhile to stipulate that unicode-bidi:isolate has
> no effect whatsoever on any element that either creates a separate UBA
> paragraph, or serves as a UBA paragraph break in its containing UBA
> paragraph. Such elements include: any element taken "out of flow" e.g.
> with float or position:absolute, any element with display other than
> "inline", <br bidibreak=hard>, <textarea>, <input type="text">. This

Elements that are out-of-flow do not affect their surrounding contents.
That is the definition of out-of-flow, and it needs no further
clarification here.  As for atomic inlines such as <textarea> and
<input>, they are handled as U+FFFC under the non-textual entities
clause (which will be further clarified in the next revision of CSS2.1)
and the bidi independence of their contents are covered by the spec text
quoted below.

> stipulation is particularly important for the display:block and <br
> bidibreak=hard> elements, for whom unicode-bidi:isolate's specification
> that the element be treated in the containing paragraph as if it were
> U+FFFC, i.e. bidi class ON, conflicts with the proposed specification
> <https://docs0.google.com/a/google.com/document/edit?id=1zR06HjhVvt7ySAJeqq7zQZSzpLTRgV8AoQNo_vNznX4&pli=1&authkey=CIXomoYI#>
> that these element be treated in the containing paragraph as if they
> were bidi class B.

The spec says

   # User agents that support bidirectional text must apply the Unicode
   # bidirectional algorithm to every sequence of inline boxes
   # uninterrupted by a forced (bidi class B) line break or block boundary.
   # This sequence forms the "paragraph" unit in the bidirectional algorithm.

In what way is this not sufficient to address your concerns?

~fantasai
Received on Sunday, 26 September 2010 14:27:24 GMT

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