title: octave saveas of custom-shape window to png saves only default window area
body: <p>In octave 3.6.2 under windows 7, when I create a window with a particular shape (not the default)</p>
  
  <pre><code>figure ('Position', [0 0 800 500])
  </code></pre>
  
  <p>draw something, and then try to save the image:</p>
  
  <pre><code>saveas(gcf, 'test.png', 'png');
  </code></pre>
  
  <p>the result saves the default area of the window, not the area as currently defined.</p>
  
  <p>If I try to set the paperposition:</p>
  
  <pre><code>set('paperposition', [.25 .25 18 4]);
  </code></pre>
  
  <p>The image shape does, in fact, change, but it is all background (white).  The graph is still on the left side, not stretched out in the shape of the window. 
  How do I print a window in its current onscreen aspect ratio, or how to specify the size and shape of png I want? </p>