XPointers in SVG

Question

I've been trying to get XPointer URIs working in an SVG file, but haven't had any luck so far. After trying something more complicated and failing, I simplified it down to just referencing an ID. However, this still fails.

The spec seems pretty clear about this implementation:

http://www.w3.org/TR/SVG/struct.html#URIReference

I found an example online of what should be a working XPointer reference within an svg document. Here is the Original. Here is the version I copied out:

<?xml version="1.0" standalone="no"?>
<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" 
    "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd&quot;&gt;
<svg width="500" height="200" version="1.1" 
    xmlns="http://www.w3.org/2000/svg&quot; 
    xmlns:xlink="http://www.w3.org/1999/xlink&quot;&gt;

    <defs>
        <rect id="simpleRect" width="100px" height="75px"/>
    </defs>
    <use xlink:href="#simpleRect" 
        x="50" y="50" style="fill:red"/>
    <use xlink:href="#xpointer(id('simpleRect'))" 
        x="250" y="50" style="fill:yellow"/>
</svg>

This should display two rectangles... one red and one yellow. I tried rendering with Firefox 3.6 and Inkscape 0.47. No success. Only the Red rectangle shows.

What am I missing?

Thanks for any help you can offer

Answer 1

From the linking section of the spec:

<URI-reference> = [ <absoluteURI> | <relativeURI> ] [ "#" <elementID> ]    -or-
<URI-reference> = [ <absoluteURI> | <relativeURI> ] [ "#xpointer(id(" <elementID> "))" ]

So what is the benefit of using xpointer syntax? All svg implementions I've seen have supported the alternative (shorter) syntax shown above (#myId). The xpointer syntax seems to be less well supported.