The TransformRef value

Hi All,

Can any one please explain me briefly about this TransformRef value & what
is its interpretation.

I went through the SVGT 1.2 & thought i understood the explanation.But when
i tried the example given there in Internet Explorer/my own SVG engine, i am
not able to see the same result as explained in the spec.

May be, the engine does not support it or may be i am not understanding
completely the explanation given in the spec.

The example is
<svg xml:id="root" viewBox="0 0 100 100" version="1.2" baseProfile="tiny">

    <line x1="0" x2="100" y1="0" y2="100"/>

    <rect xml:id="r" transform="ref(svg)"

          x="45" y="45" width="10" height="10"/>

</svg>
The explanation for the above example is
Consequently, regardless of the user transform (currentTranslate,
currentScale, currentRotate) the rectangle's coordinates in viewport space
will *always* be: (45, 45, 10, 10)*scale(2) = (90, 90, 20, 20). Initially,
the line is from (0, 0) to (200, 200) in the
viewport<http://www.w3.org/TR/SVGMobile12/intro.html#TermViewport>coordinate
system. If we apply a user agent zoom of 3 (currentScale = 3),
the rectangle is still (90, 90, 20, 20) but the line is (0, 0, 600, 600) and
the marker no longer marks the middle of the line.

What is this user agent zoom? Is it like zooming ur browser window?Is there
any other way to get the same effect of user agent zoom without zooming the
browser window(e.g.may be specifying applying transform=scale(3)" in the svg
file).

Thanks in advance for your help,
Regs,
Mustaf