- From: Martin Duerst <duerst@it.aoyama.ac.jp>
- Date: Thu, 28 Aug 2008 16:33:28 +0900
- To: Matitiahu Allouche <matial@il.ibm.com>
- Cc: www-international@w3.org
Hello Mati, others, One more question: Is there a way to have an embedding (or also an override) behave in the way that at least I and Richard seem to have expected (i.e. just behaving like a single character/object of the respective directionality on the outside). Currently, it seems to me that adding ‎ (or ‏ if rtl) before and after might work, but I'm really not sure. Regards, Martin. At 10:35 08/08/28, Martin Duerst wrote: >Hello Mati, > >Many thanks for your very quick and precise answer. > >Thinking over dinner and breakfast (or some other similar >occasions between my two work days), I started to suspect >as much as you confirm below. > >At 07:22 08/08/28, Matitiahu Allouche wrote: > >> Hello, Martin! >> >>It seems to me that it is working as designed. > >But would we be able to say that it works as intended? > >Of course, intent is difficult to capture, but my guess >would be that to a large number of people, a LTR embedding >is something very inherently and strongly LTR, and should >therefore behave as such to the outside. > >Also, one could immagine that it would be desirable to >have the following preservation property of the bidi >algorithm: If a sequence of strong LTR characters >(or, a sequence of characters displayed currently as >LTR) is wrappend in an LTR embedding, the display order >doesn't change (and of course, same for RTL). The current >behavior clearly doesn't exhibit this preservation property. > >Do you (or anybody else) have any idea why the algorithm is >designed this way? Was this aspect overlooked? Are there other >considerations that justify this behavior? Would it be too >difficult to describe an algorithm that exhibited the above >preservation property? Is this case too rare in practice to >be relevant? > >Regards, Martin. > > >>Case 1 has a default direction equals to LTR, meaning a paragraph embedding level equal to 0. The Arabic words implicitly raise the level to 1 at their location. Simple. >> >>Case 2 starts similarly, i.e at embedding level 0. The span with dir="ltr" is equivalent to a LRE. It raises the embedding level to the next even number, which is 2 (rule X3 of UAX #9). The English words within the span will receive level 2, and the Arabic word will receive level 3 (rule I1). >>The Arabic word following the span is at level 1, like in case 1 (rule I1). >>So you have a span at level 2 immediately followed by an Arabic word at level 1. The regular rules (L2) say that the span will be displayed on the right side of the Arabic word. >> >>Is that clear? >> >>Shalom (Regards), Mati >> Bidi Architect >> Globalization Center Of Competency - Bidirectional Scripts >> IBM Israel >> Phone: +972 2 5888802 Fax: +972 2 5870333 Mobile: +972 52 2554160 >> >> >> >>Martin Duerst <duerst@it.aoyama.ac.jp> >>Sent by: www-international-request@w3.org >> >>27/08/2008 13:44 >>To >>www-international@w3.org >>cc >>Subject >>Weird bidi behavior? >> >> >> >> >> >>Can somebody explain the bidi behavior of Case 2 at >>http://www.sw.it.aoyama.ac.jp/2008/pub/bidi-test.html ? >>The only difference between Case 1 and Case 2 is that >>Case 2 uses dir='ltr' on the green <span>. >> >>Regards, Martin. >> >> >>#-#-# Martin J. Du"rst, Assoc. Professor, Aoyama Gakuin University >>#-#-# http://www.sw.it.aoyama.ac.jp mailto:duerst@it.aoyama.ac.jp >> > >#-#-# Martin J. Du"rst, Assoc. Professor, Aoyama Gakuin University >#-#-# http://www.sw.it.aoyama.ac.jp mailto:duerst@it.aoyama.ac.jp #-#-# Martin J. Du"rst, Assoc. Professor, Aoyama Gakuin University #-#-# http://www.sw.it.aoyama.ac.jp mailto:duerst@it.aoyama.ac.jp
Received on Thursday, 28 August 2008 07:34:48 UTC