title: SVG: color of the shadow
body: <p>I want to write a simple rectangle with a red shadow in SVG.
  I have a simple filter:</p>
  
  <pre><code>&lt;svg xmlns="http://www.w3.org/2000/svg" version="1.1" width="1012" height="400"&gt;
    &lt;title&gt;svg arrow with dropshadow&lt;/title&gt;
    &lt;desc&gt;An svg example of an arrow shape with a dropshadow filter applied. The dropshadow filter effect uses feGaussianBlur, feOffset and feMerge.&lt;/desc&gt;
    &lt;defs&gt;
      &lt;filter id="dropshadow" filterUnits="userSpaceOnUse" color-interpolation-filters="sRGB"&gt;
       &lt;feComponentTransfer in="SourceAlpha"&gt;
           &lt;feFuncR type="discrete" tableValues="1"/&gt;
           &lt;feFuncG type="discrete" tableValues="0"/&gt;
           &lt;feFuncB type="discrete" tableValues="0"/&gt;
       &lt;/feComponentTransfer&gt;
       &lt;feGaussianBlur stdDeviation="2"/&gt;
       &lt;feOffset dx="0" dy="0" result="shadow"/&gt;
       &lt;feComposite in="SourceGraphic" in2="shadow" operator="over"/&gt;
     &lt;/filter&gt;
    &lt;/defs&gt;
    &lt;rect rx="2" ry="2" fill="rgb(255,255,255)" x="5.25" y="5.25" width="141" height="50" fill-opacity="0.85" filter="url(#dropshadow)"&gt;
  &lt;/svg&gt;
  </code></pre>
  
  <p>Why in this example shadow color is not red? Where is my bad?</p>