title: Fabric.js - Setting height changes to incorrect value or doesn't change
body: <p>thanks for looking,
  I'm currently playing with Fabric.js hoping to develop a custom product designer.</p>
  
  <p>I have a button which triggers a function to resize a user added image to the product's design area.</p>
  
  <p>I've been fiddling with a problem I can't seem to find a work around for:</p>
  
  <p><code>prod_back_height</code> is set to the design area's height, in my demo this is <code>438</code>.</p>
  
  <p>When the function runs, it sets the height for the image using <code>aw_img.set({height:prod_back_height});</code> or <code>aw_img.height=prod_back_height;</code>. The problem is this doesn't change the height to <code>prod_back_height</code>, and instead stays the same. This only occurs if the image has been resized vertically before clicking the button.</p>
  
  <p>When attempting to change the value to a specific value, I get unexpected results:</p>
  
  <p><code>aw_img.set({height:10});</code> returns <code>10.364464692482915</code> when calling <code>aw_img.getHeight()</code></p>
  
  <p><code>aw_img.set({height:500});</code> returns <code>514.8063781321185</code> when calling <code>aw_img.getHeight()</code></p>
  
  <p><code>aw_img.set({height:600});</code> returns <code>613.6674259681093</code> when calling <code>aw_img.getHeight()</code></p>
  
  <p>And I think you get my point, has anyone else came across this or know a work-around?</p>
  
  <p>Full code can be found <a href="http://www.powerbank.info/xpd-test/index-test.php" rel="nofollow">here</a>. (apologies in advance for messy code!) [currently only testing for images wider then design area's aspect ratio with the product angled as it is e.g. <a href="http://i58.tinypic.com/npjna0.jpg" rel="nofollow">this image</a> ] - has been updated, see edit.</p>
  
  <p>Thanks for reading! :)
  Colby</p>
  
  <p>edit: Now prepared to work for all image ratios and product rotated anyway, but image must stay the same at the moment.</p>
  
  <p>It seems to be that it is resizing it in proportion to how much the user has scaled the image manually E.g. If they drag the image smaller, the outcome of the 'Fit Image To Design Area' will be smaller than expected.</p>