Turning image interpolation off.

While attempting to write a test case for my implementation of
<feConvolveMatrix>, I was wanting to display an image without any
filtering/interpolation.

<?xml version="1.0" encoding="utf-8"?>
<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="
http://www.w3.org/1999/xlink"
     width="100%" height="100%" viewBox="0 0 17 17" >

  <defs>
    <filter id="test1" filterRes="3" x="0" y="0" width="1" height="1">
      <feConvolveMatrix order="3" kernelMatrix="0.5 0.5 0.5 0.5 3 0.5 0.5
0.5 0.5"/>
    </filter>

  </defs>

  <image x="7" y="2" width="3" height="3" xlink:href="swatch3x3.png"
filter="url(#test1)"/>

</svg>


Unfortunately, all the browsers (WK/FF/IE) interpolate even when
image-rendering="optimizeSpeed" is applied.

After a bit of research, I gather that some browsers supported (past-tense)
an "optimize-contrast" option for "image-rendering". What happened to that?

In any case, should there be a way to force non-interpolated rendering?


Paul