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Re: Alignment of paragraphs with unicode-bidi: plaintext

From: Matitiahu Allouche <matial@il.ibm.com>
Date: Mon, 31 Oct 2011 11:35:14 +0200
To: "Aharon (Vladimir) Lanin" <aharon@google.com>
Cc: public-i18n-bidi@w3.org, Simon Montagu <smontagu@smontagu.org>, "www-style@w3.org" <www-style@w3.org>
Message-ID: <OF64EA033A.1C3A3C2F-ONC225793A.002D61E0-C225793A.002F333F@il.ibm.com>
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 

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 

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.


On Sun, Oct 30, 2011 at 1:28 PM, Simon Montagu <smontagu@smontagu.org> 
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 Monday, 31 October 2011 08:38:54 UTC

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