title: Center a CCLabelTTF on a CCSprite
body: <p>I have a simple <code>CCLayer</code> subclass with a circle as the background image. I also have a <code>CCLabelTTF</code> as a child node. <strong>How can I center the label's text on the background image?</strong></p>
  
  <p>Here's what I have:</p>
  
  <pre><code>// in MyCCLayer's init method
  CCSprite *backgroundImage = [CCSprite spriteWithFile:@"circle.png"];
  [self addChild:backgroundImage];
  self.contentSize = backgroundImage.contentSize;
  
  CCLabelTTF *label = [CCLabelTTF labelWithString:@"0" 
                                           dimensions:self.contentSize 
                                            alignment:UITextAlignmentCenter 
                                             fontName:@"Arial" 
                                             fontSize:32];
  [self addChild:label];
  </code></pre>
  
  <p>I've tried changing the anchorPoint and position on the label but I can't get the text to just be centered on the background image. The text is always offset. I'd like to have centered text regardless of the font size.</p>