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RE: IRIs and bidi: Addition regarding higher-level protocols

From: Martin Duerst <duerst@w3.org>
Date: Thu, 12 Feb 2004 11:01:57 -0500
Message-Id: <4.2.0.58.J.20040212104939.083a6e58@localhost>
To: "Jony Rosenne" <rosennej@qsm.co.il>, <public-iri@w3.org>
Cc: <bidi@unicode.org>

Hello Jony,

It turns out that for pure RTL IRIs, both an overall left-to-right
direction and an overall right-to-left direction results in the
same display order, right-to-left. You can (almost) see this in
the examples at http://www.w3.org/International/iri-edit/BidiExamples,
the one that comes closest is example 3.

This actually was one reason for going with *overall* left-to-right
direction, as opposed to component-wise left-to-right direction.

Regards,    Martin.

At 06:50 04/02/12 +0200, Jony Rosenne wrote:

>I see why it would be desirable to demand an overall left-to-right direction
>for mixed (LTR and RTL) IRIs, but not for pure RTL IRIs in an RTL
>environment.
>
>This requirement should be changed.
>
>Jony
>
> > -----Original Message-----
> > From: public-iri-request@w3.org
> > [mailto:public-iri-request@w3.org] On Behalf Of Michel Suignard
> > Sent: Thursday, February 12, 2004 3:05 AM
> > To: Martin Duerst
> > Cc: public-iri@w3.org; Mark Davis
> > Subject: RE: IRIs and bidi: Addition regarding higher-level protocols
> >
> >
> >
> > Martin, here is my new proposed text (in quotes) for
> > replacement ofn the 2nd paragraph of clause 4.1:
> >
> > <<
> > When rendered, bidirectional IRIs MUST be rendered using the
> > Unicode Bidirectional Algorithm [UNIV4] [UNI9] with an
> > overall left-to-right
> > (ltr) direction. To achieve this, the IRI is embedded
> > left-to-right in all the following cases: 1. If the current
> > embedding level before the IRI is odd (right-to-left) 2. If
> > the last character with a strong directionality before the
> > IRI is right-to-left 3. If the first character with a strong
> > directionality after the IRI is right-to-left. No additional
> > bidirectional rendering change by higher-level protocols is allowed.
> >
> > Note: Embedding the IRI left-to-right can be achieved by
> > embedding the text with LRE...PDF. If the maximum allowed
> > embedding level is exceded (above 62), the IRI overall
> > left-to-right direction may not be enforced.
> > >>
> >
> > The small diagramm (to be seen in monospaced chars) shows the
> > desired result
> >
> > -String before-|  IRI  |-String after--
> >               L    ON   L
> > (For the string before and after, the IRI behaves as bidi
> > 'ON') (For the IRI itself, string before and after behave as bidi 'L')
> >
> > BTW I am interpreting clause W2 of the Unicode Bidi algorithm
> > concerning the strong type enumeration as including as well
> > the embedding characters (at least the LRE) as it is
> > necessary in the logic expressed above. I have tried one of
> > the sample bidi algorithm (Asmus Freytag
> > version) and it behaves that way.
> >
> > Michel
> >
> >
> >
Received on Thursday, 12 February 2004 13:16:24 UTC

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