title: about the shadow of mask layer
body: <p>when i set the cell imageView shadow like this:</p>
  
  <pre><code>[[[self imageView] layer] setShadowColor:[[UIColor redColor] CGColor]];
  [[[self imageView] layer] setShadowOffset:CGSizeMake(1, 2)];
  [[[self imageView] layer] setShadowOpacity:1.0];
  [[[self imageView] layer] setShadowRadius:MASK_LAYER_RADIUS];
  
  
  self.maskLayer = [[[CALayer alloc] init] autorelease];
  [_maskLayer setFrame:CGRectMake(0, 0, [UIImage imageNamed:name].size.width, [UIImage imageNamed:name].size.height)];
  [_maskLayer setBackgroundColor:[[UIColor grayColor] CGColor]];
  [_maskLayer setCornerRadius:MASK_LAYER_RADIUS];
  [_maskLayer setOpacity:MASK_LAYER_OPACITY];
  [_maskLayer setShadowColor:[[UIColor greenColor] CGColor]];
  [_maskLayer setShadowOffset:CGSizeMake(1, 2)];
  [_maskLayer setShadowOpacity:1.0];
  [_maskLayer setShadowRadius:MASK_LAYER_RADIUS];
  [self.imageView.layer setMask:_maskLayer];
  </code></pre>
  
  <p>i'm sorry  i can't upload the image of effect</p>
  
  <p>when i runing  i find  the  ShadowRadius have no effect? i can see the corner </p>
  
  <p>thanks.</p>