SVG Essentials – Filters

This is a recreation (for the purpose of tinkering with an implementation in d3.js) of the example from the book SVG Essentials by J. David Eisenberg.

The <feColorMatrix> element allows to change color values in a following way.

<filter id="glow">
  <feColorMatrix type="matrix" values=
     "0 0 0 red   0
      0 0 0 green 0
      0 0 0 blue  0
      0 0 0 1     0"/>
  <feGaussianBlur stdDeviation="number" result="coloredBlur"/>
  <feMerge>
    <feMergeNode in="coloredBlur"/>
    <feMergeNode in="SourceGraphic"/>
  </feMerge>
</filter>