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Re: Alignment of paragraphs with unicode-bidi: plaintext

From: Aharon (Vladimir) Lanin <aharon@google.com>
Date: Tue, 6 Dec 2011 10:30:46 +0200
Message-ID: <CA+FsOYaXNcaFZQWDR5U8ev9bnc-758d4LUgDVHML2qSpg_=_QA@mail.gmail.com>
To: Ryosuke Niwa <rniwa@webkit.org>
Cc: Matitiahu Allouche <matial@il.ibm.com>, Simon Montagu <smontagu@smontagu.org>, "www-style@w3.org" <www-style@w3.org>, public-i18n-bidi@w3.org
Adding public-i18n-bidi back to the thread.

On Tue, Dec 6, 2011 at 10:08 AM, Ryosuke Niwa <rniwa@webkit.org> wrote:

> I'd prefer to wait until the spec change is made. We'd have to do some
> refactoring, etc... to support this in WebKit so it'll take us a while
> anyway.
>
> - Ryosuke
>
> On Mon, Dec 5, 2011 at 11:38 PM, Aharon (Vladimir) Lanin <
> aharon@google.com> wrote:
>
> 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 coming.
>>
>> Fantasai, any guidance?
>>
>> Aharon
>>
>> On Mon, Oct 31, 2011 at 5:52 PM, Aharon (Vladimir) Lanin <
>> aharon@google.com> wrote:
>>
>>> 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 08:31:37 GMT

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