title: Calculate center of SVG arc
body: <p>I have the following information:</p>
  
  <ul>
  <li>radiusX (rx)</li>
  <li>radiusY (ry)</li>
  <li>x1</li>
  <li>y1</li>
  <li>x2</li>
  <li>y2</li>
  </ul>
  
  <p>The SVG spec allows you to define an arc by specifying its radius, and start and end points. There are other options such as <code>large-arc-flag</code> and <code>sweep-flag</code> which help to define how you want the start-point to reach the end-point. <a href="http://www.w3.org/TR/SVG/paths.html#PathDataEllipticalArcCommands" rel="noreferrer">More details here</a>.</p>
  
  <p>I am not mathematically inclined, so understanding <a href="http://www.w3.org/TR/SVG/implnote.html#ArcImplementationNotes" rel="noreferrer">all of this</a> is near impossible.</p>
  
  <p>I guess I am looking for a simple equation that results in me knowing the <code>centerX</code> and <code>centerY</code> values given all the arguments accepted by SVG's arc command.</p>
  
  <p>Any help is appreciated.</p>
  
  <p>I've search stackoverflow and none of the answers seem to explain the solution in plain english.</p>