title: Same origin policy, google chrome, canvas and file:// scheme
body: <p>When trying to read image data from a canvas which was painted an image upon beforehand, Google Chrome raises a cross origin exception (complaining about the canvas being "tainted").  The directory structure is as follows.</p>
  
  <pre><code>/html/base/path
  |-- index.html         contains the canvas element, references the script.js
  |-- script.js          loads imgs/images.jpg, paints and queries the canvas
  `-- imgs/image.jpg
  </code></pre>
  
  <p>The error occurs only when the page was loaded by the file:// scheme.</p>
  
  <p>I wonder whether this is a Chrome bug.  If not, which rules do apply?  Are there any workarounds? </p>
  
  <p>Unfortunately, off-line viewing is the ultimate use case, so </p>
  
  <ul>
  <li>the file:// scheme is indispensable</li>
  <li>there is no control over browser settings at the target system.</li>
  </ul>