title: Get transformed coordinates with canvas
body: <p>If I use a transformation function like <code>translate</code>/<code>rotate</code> on a canvas, then all points are transformed when passed to any canvas function. This works like a charm, but is there also a way to simply get the transformed point without actually drawing?</p>
  
  <p>This will be extremely helpful when debugging. All I can do now is looking where the point ends up, but I cannot seem to obtain the calculated transformed coordinates.</p>
  
  <p>So, say I rotate 90 degrees, is there any function that takes a point (i.e. <code>(10, 0)</code>) and gives the transformed point back (i.e. <code>(0, 10)</code>)?</p>
  
  <p>I basically mean something like this:</p>
  
  <pre><code>ctx.rotate(90 * Math.PI / 180);
  ctx.transformed(10, 0); // would return (0, 10) as an array or something
  </code></pre>