title: iPhone: Blur UIImage
body: <p>In my iPhone application I have a black-and-white <code>UIImage</code>. I need to blur that image (Gaussian blur would do).</p>
  
  <p>iPhone clearly knows how to blur images, as <a href="http://developer.apple.com/iphone/library/documentation/GraphicsImaging/Conceptual/drawingwithquartz2d/dq_shadows/dq_shadows.html" rel="noreferrer">it does that when it draws shadows</a>.</p>
  
  <p>However I did not found anything related in the API.</p>
  
  <p>Do I have to do blurring by hand, without hardware acceleration?</p>