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Re: Alignment of paragraphs with unicode-bidi: plaintext

From: Ryosuke Niwa <rniwa@webkit.org>
Date: Tue, 6 Dec 2011 00:08:00 -0800
Message-ID: <CABNRm60U7RMyhTCh2kZoy24yeTJTAzQDdYv5JJf5t8DXuviEbA@mail.gmail.com>
To: "Aharon (Vladimir) Lanin" <aharon@google.com>
Cc: Matitiahu Allouche <matial@il.ibm.com>, Simon Montagu <smontagu@smontagu.org>, "www-style@w3.org" <www-style@w3.org>
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

- Ryosuke

On Mon, Dec 5, 2011 at 11:38 PM, Aharon (Vladimir) Lanin <aharon@google.com>

> 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 08:08:49 UTC

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