<!DOCTYPE html>
<title>Filter Effects: The in attribute</title>
<link rel="author" title="Cameron McCormack" href="mailto:cam@mcc.id.au">
<link rel="help" href="https://www.w3.org/TR/filter-effects-1/#CommonAttributes">
<link rel="match" href="svg-unknown-input-ref.html">
<meta name="flags" content="svg">
<meta name="assert" content="References to non-existent results on a subsequent primitive must be treated like the previous primitive result.">
<p>The test passes if you see a green square and no red.</p>
<svg width="100" height="100">
  <defs>
    <filter id="f" x="0" y="0" width="100" height="100" filterUnits="userSpaceOnUse">
      <feFlood flood-color="green"/>
      <feComposite in="unknown" in2="SourceGraphic"/>
    </filter>
  </defs>
  <rect width="100" height="100" fill="red"/>
  <rect x="25" y="25" width="50" height="50" fill="blue" filter="url(#f)"/>
</svg>
