title: iOS sdk, render image from unsigned char array, CGBitmapContextCreate returns NULL
body: <p>I have an <strong>unsigned char* data</strong> with the following values, as seen while debugging in xcode, </p>
  
  <p><strong>\xc1\xc1\xc1\xc1\xc1\xc1\xc1\xc0\x84\x03\x03\x02\x03\x02\x03\x03\x03\x02\x02\x03\x02\x03\x02\x02\x03\x02\x02\x02\x02\x03\x03\x03\x03\x03\x02\x02\x03\x03\x03\x02\x02\x03\x02\x02\x02\x02\x03\x03\x03\x02\x02\x02\x02\x03\x02\x03\x02\x03\x02\x03\x02\x03\x02\x03\x02\x02\x02\x03\x03\x03\x03\x03\x02\x03\x02\x03\x02\x03\x03\x02\x02\x03\x03\x03\x02\x02\x02\x02\x02\x03\x02\x02\x03\x02\x03\x02\x02\x03\x03\x03</strong></p>
  
  <p>This is the data array for a qr code.</p>
  
  <p>Symbol data is represented as an array contains width*width uchars. Each uchar represents a module (dot). If the less significant bit of the uchar is 1, the corresponding module is black.</p>
  
  <p>In the above case the width is <strong>177</strong>.</p>
  
  <p>I have tried various combination in CGBitmapContextCreate, but always seem to get NULL.</p>
  
  <p>Please advise.</p>
  
  <p>Your help will be much appreciated.</p>