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Re: Renderers and XSL-FO, plus other thoughts...

From: Dave Pawson <daveP@dpawson.freeserve.co.uk>
Date: Wed, 31 Jan 2001 05:49:56 +0000
Message-Id: <>
To: <www-xsl-fo@w3.org>
At 03:00 AM 1/31/01, Arved Sandstrom wrote:
>Hi, all
>I'm interested in soliciting comments regarding interfaces for XSL-FO processors, and the possible use of FO as an interchange format irrespective of the existence of FO processors.

I speak very strongly against this Arved.
Rationale. The WAI asked for a statement to be added to the WD to the effect 
that fo was an intermediate format, i.e. not an interchange format.
Rationale? Accessibility. Its difficult, if not impossible, for an eyes free
access to fo documents. 
There was (is?) one app on the web which permits viewing of fo objects,
and this was felt to be an indication that this might happen.

My preference is for fo's in their original guise, ie a means of getting
xml source documents into a (normally paper based) rendered form.

>Let us define the software that accepts FO as input, and produces a formatted area tree (as stipulated by the XSL specification) as output, as a "formatter", for the sake of this discussion. It seems to me that "renderers", that is, translators from area-tree information into print-quality output formats, would (should?) be restricted to stuff like PDF, PostScript, and the like. That is, _rendering-level_ translation happens at the back-end. And it happens with formats that can support the goals of the original FO, not with HTML or RTF.
>My feeling is that there is nothing to be gained by having, say, an RTF "renderer", since the real correspondence is between the FO (XSLT result tree) at the formatter front-end and RTF, not between the formatter _output_ and RTF. That is, _formatting-level_ translation happens at the front-end.
>What are the opinions on this division? I think it is reasonable.

 From an intuitive viewpoint, this feels wrong. Just 'where' within fop/xep etc
the transition takes place from fo's to "something I can view" (pdf/RTF), from
a user view I don't care. Can you see this view of things?

>Related issue: pros & cons of using FO as a common interchange format for formatting "languages"? I have no strong feelings either way, but the possibility is there. Advantage being is that it would be XML, and hence easily processed by ubiquitous and reliable tool sets. It would also be a relatively high-end interchange format, arguably better than CSS even in its latest incarnations. Comments?

-1 for me, see above.

>Final thought: do users believe that formatter flexibility in also accepting CSS would be a boon? The formatting model is shared (in theory) between CSS and XSL-FO. A formatter that accepts CSS-styled XML could present pretty much the same formatting-object tree to the formatter as we get through FO. Or so goes the possible argument. Is consideration of this worthwhile? What do people think?

For someone without the bandwidth to take on board fo's, CSS might be an easy in?
I think such a user would soon see the restrictions of CSS1 or even 2.
If you were talking 3 then perhaps yes.

Regards DaveP
Received on Wednesday, 31 January 2001 00:51:33 UTC

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