title: CGAffineTransformInvert: singular matrix
body: <p>I've been occasionally seeing the error message:</p>
  
  <pre><code>CGAffineTransformInvert: singular matrix
  </code></pre>
  
  <p>In the logging area of Xcode.  This seems to occur (infrequently, fortunately) when I pinch to resize a web site within a UIWebView.  [Commercial website, not my own.]  Since I do no Affine Transformations in my App, I'm wondering if this might be a bug/feature of UIWebView.  If so, can I ignore it, since it doesn't seem to be interfering with anything?</p>