title: CABasicAnimation originates from top right rather than center
body: <p>I have a circle that I animate growing outwards and getting bigger.  Unfortunately despite me setting the <code>anchorPoint</code> it doesnt animate from the center outwards, it seems to lock position top left.  What is going on?</p>
  
  <p>See this image that depicts the circles off center</p>
  
  <p><img src="https://i.stack.imgur.com/Tk69j.png" alt="enter image description here"></p>
  
  <p>Code</p>
  
  <pre><code>- (void)setLayerProperties {
      rippleLayer = [[CAShapeLayer alloc] init];
      rippleLayer.fillColor = [UIColor clearColor].CGColor;
  
      rippleLayer.strokeColor = _Color.CGColor;
      //rippleLayer.contentsGravity = @"center";
      rippleLayer.anchorPoint = CGPointMake(0.5,0.5);
      rippleLayer.bounds = self.bounds;
  
      rippleLayer.path = bezierPath.CGPath;
      [self.layer addSublayer:rippleLayer];
  }
  
  // Now animate the circle outwards
  rippleLayer.opacity = 1;
  CABasicAnimation *scale = [CABasicAnimation animationWithKeyPath:@"transform.scale"];
  [scale setFromValue:[NSNumber numberWithFloat:1.0f]];
  [scale setToValue:[NSNumber numberWithFloat:2.0f]];
  [scale setRepeatCount:1];
  [scale setDuration:1.0f];
  //[scale setRemovedOnCompletion:YES];
  [scale setFillMode:kCAFillModeForwards];
  
  [rippleLayer addAnimation:scale forKey:scale.keyPath];
  </code></pre>