Re: XAG 2.3 and xlink

Well, it would break the current approach of everything in attributes, but
extended Xlinks should be readily useable by having the other links as
children.

As you point out in your other message [1], this changes the authoring model
slightly from SVG/HTML. On the other hand, your example looks a lot like a
SMIL switch statement or an object element:

Jim's example:
  <image xlink:href="shepherds.jpg">
    <alternative xlink:href="shepherds.html" type="text/html">
    <alternative xlink:href="shepherds.rdf" type="application/rdf+xml">
    <alternative xlink:href="shepherds.svg" type="image/svg+xml">
  </image>

Consider the following:

   <mediaExample xlink:href="example">

     <alt xlink:role="http://example.au/equivalenceTypes/image"
        xlink:href="example.img" />

     <alt xlink:role="http://example.au/equivalenceTypes/hyperText"
        xlink:href="example.txt" />

     <alt xlink:role="http://example.au/equivalenceTypes/movie"
        xlink:href="example.mov" />

     A short clip of Jim beating Charles in an animating debate

   </mediaExample>

If "example" is a content-negotiated resource that can in fact provide all
the same types, then is

   <mediaExample xlink:href="example"/>

an equivalent? Should there be at least the short-text content as with the
HTML/SMIL alt attribute, or hypertext content, as with the HTML object
element? (But please not so many attributes - a plea also made in the HTML
group!)

I think it depends on the application. If you are dynamically building
content then you can have a whole lot of small blocks. How about the
following:

 <div>
     <ill xlink:role="http://example.au/equivalenceTypes/image"
        xlink:href="figure1" />
     <alt xlink:role="http://example.au/equivalenceTypes/movie"
        xlink:href="movie" />

   <p>
     <ill>
       <alt xlink:role="http://example.au/equivalenceTypes/image"
          xlink:href="figure2" />
       <alt xlink:role="http://example.au/equivalenceTypes/movie"
          xlink:href="movie" />
     </ill>
   Charles and Jim had a lively discussion about the merits of animation and
   scripting. Charles suggested that animation was virtually free, whereas
   Jim said that with a good script it was easier to understand what was
   happening and going to happen.</p>

   <p>Jim, of course, demonstrated his argument with very cogent examples,
   and so carried the day.</p>

 </div>

(where ill is an optional element to illustrate the content of its parent,
and alt is an alternative version to replace content in its parent - a la
elements in a SMIL or SVG switch)

I have used the movie both as an illustration (with a picture as an
alternate) and as an alternate for the same block.

On the one hand this is a kind of complicated example. On the other hand it
allows an author to provide various kinds of alternatives (meets 1.2), and at
the same time makes it possible to annotate various chunks (the div, a p
element, the move).

Not quite all of this can be done with attributes - if you make an alt
element into an attribute then it can't be XML that includes further alt
elements except by reference to a URI. Is that a good thing or a bad one?

[1] http://lists.w3.org/Archives/Public/wai-xtech/2002Sep/0011

Some of this is just thinking out loud...

Cheers

Chaals

On Tue, 3 Sep 2002, Jim Ley wrote:

>
>"Charles McCathieNevile" <charles@w3.org>
>
>> I don't see that your conclusion follows from your premise. It is clear
>that
>> the HTML group doesn't want to use Xlink, and equally clear that the
>SVG
>> group is happy to use it. SMIL 2 takes an intermediate position.
>
>Dean Jackson in
>http://lists.w3.org/Archives/Public/www-svg/2002Aug/0060.html
>Made a suggestion would break XLink in SVG.
>
>Jim.
>

-- 
Charles McCathieNevile  http://www.w3.org/People/Charles  tel: +61 409 134 136
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Received on Tuesday, 3 September 2002 09:55:40 UTC