Fw: About the style processing instruction

["Oren Ben-Kiki" <oren@xxxxxxxxxxxxx>]

Didier PH Martin <martind@xxxxxxxxxxxxx> wrote:


>Here is essence of the proposal about a certain usage of the "media"
>property. This is not a big thing but at least an active effort to resolve
a
>concrete problem...


I'm a bit confused about the proposed semantics of the media property. I
first took it to specify the format of the output document. You said:

"XSL and CSS and DSSSL style engines, may allow an output format choice. To
fully support such capacity, the media property can be used to set the
desired output type."

I took this to mean that the XSL engine would actually create a document of
the specified type as output - e.g., a valid TeX file - instead of an XML
<fo:*> document (which would be the default). This has many implications:
specifying other XML languages (e.g., MathML), non-XML languages (e.g. TeX,
Rtf); shouldn't the format be specified as a mime type in this case? How
does this relate to the result-ns attribute? Etc.

But then you said:

"If the current rendering engine do not support such formats, it should
degrade to something
it can do".

So I revised my understanding; I took it to mean that the XSL engine should
create <fo:*> elements as usual and then translate the <fo:*> elements into
the specified type - and possibly display the document using the appropriate
back-end for this type - if it can; and do the best it can otherwise.
Shouldn't such decisions be left to the user which invoked the XSL
processor? After all, he knows which back-ends he has (Word, Adobe Acrobat
or a DVI viewer) and which one he is interested in... And the <fo:*>
document is identical in all cases. Or am I missing something?

You then said:

"The media property can specify the output device (print, screen etc...) and
the
rendering model. The rendering model could be expressed by a format like DXF
and thus be implicit or explicitly mentioned by a general term like "3D"
..."

And I'm totally lost. How can the media attribute specify the rendering
model? This is fixed by the <fo:*> language. Do you mean that the <fo:*>
language can be extended with "some macros specific to 3D" so that it would
be possible to use the same output document for print, screen and _3D_? And
similarly for any other model we might come up with - e.g., visualization
graphs, sounds, force-feedback, ...? Just reconciling the 2D <fo:*> model
with a 3D model would be one hell of an achievement. Shouldn't this be
better left to a different stylesheet per rendering model "family" (2D, 3D,
...) - presuming an XML language is defined for each (e.g. VRML for 3D)?

So... What exactly should "media" mean?

Share & Enjoy,

    Oren Ben-Kiki


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