Re: [docbook-apps] Writing mode, xsl-fo output

[Dave Pawson <davep@dpawson.co.uk>]

On Fri, 01 Apr 2011 14:08:07 -0400
maxwell <maxwell@umiacs.umd.edu> wrote:

> On Fri, 1 Apr 2011 10:40:16 -0700, "Bob Stayton" <bobs@sagehill.net>
> wrote:
> > But when you say "some rl-tb" text, do you mean a mixed language
> document?
> > In that case, the writing mode value should be for the dominant
> language, 
> > since the document's writing mode determines the page layout.. 
> > Any inline translated text should get the 
> > correct text direction based on its Unicode character range.
> 
> That last sentence--that the writing direction can be determined by
> inspecting the characters--is a common intuition (it was once my own
> intuition).  But it isn't quite that simple, since some symmetrical
> punctuation marks belong sometimes to L2R text, and sometimes to R2L
> text. For example, an ASCII period at the end of a run of R2L text
> might belong at the left end of the R2L text, or--if the R2L text is
> at the end of an L2R text--it might belong at the right end of the
> L2R text (and therefore at the right end of the R2L text).  
> 
> Unsymmetrical punctuation marks sometimes exist as distinct L2R and
> R2L code points in Unicode, like the ASCII comma vs. the Arabic comma
> U+060C. But Parentheses (which of course are asymmetrical) are also
> sometimes used inside runs of R2L text--I've seen them in Urdu, for
> example.  Here I believe the ASCII open parenthesis is used as an
> Urdu close paren, and vice versa.
> 
> Space characters of course also fall into this category of ambiguous
> direction, although that's generally handled correctly by algorithmic
> methods.
> 
> There's been considerable discussion of this general issue (whether
> it's possible to algorithmically determine the ends of an R2L run
> inside an L2R run, or vice versa) over on the XeTeX mailing list.
> The opinion of Those Who Know seems to be that it is not 100%
> decidable.
> 
>    Mike Maxwell


I think I would rather specify what I'm writing rather than
leave it to the code point.

Although I'm unsure who / what would do that? The formatter?




-- 

regards 

-- 
Dave Pawson
XSLT XSL-FO FAQ.
http://www.dpawson.co.uk