RE: DOCBOOK-APPS: How to select <imageobject> alternative in <mediaobject>?

[Jeff Beal <jeff.beal@ansys.com>]

I agree that role is the best attribute for the author specifying which
object to use for which output.  I don't think that simply 'html' and 'fo'
will be able to satisfy every condition, though.  For example, we support a
wide variety of platforms and many of our UNIX users use an X Windows
emulator to run our application from their Windows desktop.  Using the
audioobject would not work, simply because sound doesn't work in that
configuration.  However, we may want to use an audioobject for our Windows
users.  There are probably several other examples.  (e.g. different image
support between XEP and FOP)

I think that if you add a "preferred.mediaobject.role" parameter, we can
modify the selection algorithm as follows:

1) Look for an object with "@role = $preferred.mediaobject.role"
2) Look for an object where the role matches the output (html or fo)
3) Pick the first object with either role="all" or no role attribute
4) Look for a textobject

Jeff Beal

-----Original Message-----
From: Bob Stayton [mailto:bobs@caldera.com]
Sent: Monday, November 25, 2002 11:25 PM
To: docbook-apps@lists.oasis-open.org
Subject: Re: DOCBOOK-APPS: How to select <imageobject> alternative in
<mediaobject>?


The mediaobject element can contain more than one
imageobject element, with the intent being to use 
one from the set for a given output.  But
there currently isn't an easy way of designating this
particular imageobject for HTML output and that
one for FO output.

I suggested in a previous message that role="html" or
role="fo" in each imageobject could be used, with a
stylesheet customization to act on the role value.  I'm
wondering if this method would be appropriate as a standard
feature of the stylesheets? That is, should the stylesheets
designate the role attribute as the method to select
which imageobject to use?    

Let me be clear that this is not a change to the DTD, but
just a convention to be used with Norm's XSL stylesheets.

There doesn't seem to be another available attribute that
would be appropriate.  And I'm guessing that any profiling
would probably be done on the role attribute in
mediaobject, rather than the individual imageobjects within
it.

But I'd like to hear what others think.
Would this be useful?  Is there a better way to do it?


Bob Stayton                                 400 Encinal Street
Publications Architect                      Santa Cruz, CA  95060
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                                            email: bobs@sco.com