SVG images often don't have an intrinsic size. What's the intrinsic
size of
this image?
<svg xmlns="http://www.w3.org/2000/svg";>
<linearGradient id="g" x1="0" y1="0" x2="1" y2="0">
<stop stop-color="red" offset="0"/><stop stop-color="lime"
offset="1"/>
</linearGradient>
<rect x="0%" y="0%" width="100%" height="100%" fill="url(#g)"/>
</svg>
That <svg> hasn't got intrinsic sizes, so it cannot be rendered on a
canvas. This doesn't preclude the use of <svg> with intrinsic sizes,
that are given only by width/height attributes on <svg>.
That's really really bad, as that means sometimes drawing you svg will
work, and sometimes it won't. That's why it's a bad API.
--Oliver
