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Re: Alignment of paragraphs with unicode-bidi: plaintext

From: Aharon (Vladimir) Lanin <aharon@google.com>
Date: Tue, 6 Dec 2011 09:38:59 +0200
Message-ID: <CA+FsOYaC2LTFSnGUFMRDtGoqMmBg2m3UiByGgAWDLT79Z-NU9g@mail.gmail.com>
To: Matitiahu Allouche <matial@il.ibm.com>
Cc: public-i18n-bidi@w3.org, Simon Montagu <smontagu@smontagu.org>, "www-style@w3.org" <www-style@w3.org>
https://bugs.webkit.org/show_bug.cgi?id=71194 has been filed about this on
WebKit, and there seems to be a consensus that unicode-bidi:plaintext would
work better if it affected alignment (when text-align/text-align-last is
start or end). There are two possible ways to proceed:

- Change WebKit's behavior as proposed.
- Wait for a change in the spec - or at least a sign that such a change is

Fantasai, any guidance?


On Mon, Oct 31, 2011 at 5:52 PM, Aharon (Vladimir) Lanin

> Sounds good.
> Fantasai, do you think it can be specified that way in Writing Modes level
> 3?
> Levi, how difficult would it be to implement in WebKit?
> Aharon
> On Mon, Oct 31, 2011 at 2:35 AM, Matitiahu Allouche <matial@il.ibm.com>wrote:
>> My opinion, for what it's worth, is that plaintext paragraphs should be
>> aligned in sync with paragraph direction for "text-align:start", opposite
>> to paragraph direction for "text-align:end", to absolute right or left for
>> "text-align:right" and "text-align:left" respectively.
>> "text-align:center" should not be a problem.
>> "text-align:justify" should not be a problem for lines down to the last
>> one in the paragraph. The last one should be handled like for
>> "text-align:start".
>> The advantage of this proposal is that it provides more readability for
>> common cases when most paragraphs follow the same direction and span at
>> least a few lines.
>> For special cases when there are very short paragraphs with alternate
>> directions, the author can specify "text-align:right" or "text-align:left",
>> so we get the advantages of both solutions (Gecko and Chrome).
>> Shalom (Regards),  Mati
>>       Bidi Architect
>>       Globalization Center Of Competency - Bidirectional Scripts
>>       IBM Israel
>>       Mobile: +972 52 2554160
>> From:        "Aharon (Vladimir) Lanin" <aharon@google.com>
>> To:        Simon Montagu <smontagu@smontagu.org>
>> Cc:        public-i18n-bidi@w3.org, "www-style@w3.org" <www-style@w3.org>
>> Date:        31/10/2011 00:27
>> Subject:        Re: Alignment of paragraphs with unicode-bidi: plaintext
>> ------------------------------
>> I can see arguments for either approach being better. On the one hand,
>> text is more readable aligned to its own start side. On the other hand,
>>  paragraphs with alternating alignment, especially when many are less than
>> half a line long, can look "jagged", and in extreme cases can result in the
>> user not even noticing the paragraphs aligned to the minority side.
>> Furthermore, we would need to specify how allowing plaintext to base
>> alignment on paragraph direction would play with text-align. Is it supposed
>> to be limited to "text-align:start" and "text-align:end"?
>> I would very much like to hear what people think about this.
>> Aharon
>> On Sun, Oct 30, 2011 at 1:28 PM, Simon Montagu <*smontagu@smontagu.org*<smontagu@smontagu.org>>
>> wrote:
>> As far as I can see, there is no explicit specification in CSS Writing
>> Modes Module Level 3 of what effect "unicode-bidi: plaintext" should have
>> on the default alignment of paragraphs.
>> When implementing "unicode-bidi: plaintext" for Gecko, I took it for
>> granted that each paragraph in the element would determine its
>> directionality by the heuristic in the UBA, and then determine the start of
>> the line box depending on the directionality of the paragraph.
>> I just noticed that recent versions of Chrome behave differently:
>> directionality is determined for each paragraph separately, but alignment
>> is determined by the first paragraph in the element, and all subsequent
>> paragraphs get the same alignment.
>> As I said, there doesn't seem to be anything in the spec to say which
>> approach is correct. I think the behaviour in Gecko is more intuitive and
>> useful, but then I would, wouldn't I? Either way, it is probably worth
>> adding something to the spec to make it explicit.
Received on Tuesday, 6 December 2011 07:39:59 UTC

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