title: CALayer subclass "drawInContext" called but not drawing?
body: <p>I am trying to draw in a CALayer subclass.
  The   <code>drawInContext</code>  is called with <code>setNeedsDisplay</code> but nothing is drawn.
  What am doing/getting wrong here ?</p>
  
  <pre><code> - (void)drawInContext:(CGContextRef)ctx
  {
      CGContextSetFillColorWithColor(ctx, [UIColor redColor].CGColor);
      [[UIBezierPath bezierPathWithRect:CGRectMake(100, 100, 100, 100)] fill];
  
      [@"Vowel" drawAtPoint:CGPointMake(0, 0) withFont:[UIFont fontWithName:@"Chalkboard" size:14]];
  }
  </code></pre>
  
  <p><strong>Edit</strong>
  I am getting this error :</p>
  
  <blockquote>
    <p>CGContextAddPath: invalid context 0x0</p>
  </blockquote>
  
  <p>Thanks
  Shani</p>