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Re: Need to clarify the effects of bidi paragraph breaks

From: Aharon (Vladimir) Lanin <aharon@google.com>
Date: Thu, 24 Feb 2011 11:17:49 -0800
Message-ID: <AANLkTinRdxHkqbEMSu0=5BNQ8WVv6BVnkZ2KMi5QuEKu@mail.gmail.com>
To: fantasai <fantasai.lists@inkedblade.net>
Cc: W3C style mailing list <www-style@w3.org>, "public-i18n-bidi@w3.org" <public-i18n-bidi@w3.org>
Thanks for taking care of this!

A couple of minor comments:

- The #isolate anchor seems to be undefined.

- The text you added for 3 ("If an inline element is broken around a bidi
paragraph boundary [...] and reopened on the other side of it.)") looks
good, but I think that the paragraph that follows it ("In this process [...]
neutral characters always.") is now orphaned. It might be better to put that
paragraph before the new text, which itself can be in a new paragraph.

Aharon

On Wed, Feb 23, 2011 at 11:42 PM, fantasai <fantasai.lists@inkedblade.net>wrote:

> On 12/15/2010 02:11 PM, Aharon (Vladimir) Lanin wrote:
>
>> Currently, the CSS Writing Modes Module Level 3 spec on text direction
>> <http://dev.w3.org/csswg/css3-writing-modes/#text-direction> states:
>>
>>
>> I think that these parts of the spec needs to be tweaked in several
>> respects:
>>
>> 1. There is no reason to mention rule P1 when describing how
>> unicode-bidi:plaintext affects the base directionality of each
>> paragraph. P1 deals with how the text is split up into paragraphs, not
>> with the direction of each paragraph, and applies to
>> all content, regardless of unicode-bidi:plaintext.
>>
>
> Hm, good point. Fixed.
>
>
>  2. I think it would improve clarity to mention the unicode-bidi:plaintext
>> exception when first describing how the paragraph
>> embedding level is set (first quote above). Thus, the last sentence of the
>> first quote should read:
>>
>> "The paragraph embedding level is set according to the value of the
>> ‘direction’ property of the containing block, unless the
>> containing block element has unicode-bidi:plaintext, in which case it is
>> set according to the heuristic given in steps P2 and
>> P3 of the Unicode algorithm."
>>
>
> I am.. less sure of this. I prefer to have unicode-bidi: plaintext to
> be described as an exception to the general rule than to have it be
> described as some kind of determining switch. Anyway, I've added
> some clarifying wording.
>
>  3. We must probably explicitly define the effect of a paragraph break
>> [when it splits an embedding inline]
>>
>> The overall direction of both paragraphs is ltr (P2 and P3 are
>> overridden),
>> and since the paragraph break resets all embedding levels, the [PDF] is
>> orphaned, and the question mark winds up to the right of "EB OT TON RO".
>>
>
> Good point. I've added text to this effect.
>
>
>  Does a line break does result in anonymous boxes?
>>
>
> No, just more line boxes. :)
>
>
>  4. When the path from the containing block element to the paragraph break
>> includes an element with unicode-bidi:isolate, there
>> is no reason to go back all the way to the containing block element to get
>> the new paragraph's base direction and the
>> embeddings to be reconstituted at its start. Instead of referring to the
>> containing block element, the spec should be
>> referring to the closest unicode-bidi:isolate ancestor or containing block
>> element, whichever is closer.
>>
>
> Good point. I've updated the spec for this, too.
>
> ~fantasai
>
Received on Thursday, 24 February 2011 19:22:54 GMT

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