title: Change fill color of a part of a combined path with animation?
body: <p>In simple words only part of my icon must change color at some event.</p>
  
  <p>I drawing an icon with curves inside an <code>UIView</code>. The drawing boilds
  down to combining several paths together like this (swift code):</p>
  
  <pre><code>let combinedPath = CGPathCreateMutableCopy(bezierPath.CGPath)
  CGPathAddPath(combinedPath, nil, bezier2Path.CGPath);
  CGPathAddPath(combinedPath, nil, bezier3Path.CGPath);
  </code></pre>
  
  <p>Then I'm adding the combined path to the UIView like this (obj-c, sorry for
  the mix):</p>
  
  <pre><code>CAShapeLayer *shapeLayer = [CAShapeLayer layer];
  shapeLayer.frame = self.bounds;
  shapeLayer.path = combinedPath;
  self.layer.mask = shapeLayer;
  </code></pre>
  
  <p>And now at some point in time I want to change the fill color of
  only one <code>bezierPath</code> with animation. How can I do this?</p>