title: Change generated image resolution Fabric.js
body: <p>I'm creating a <code>Fabric.js</code> based image editor, but I have a problem with final image resolution. I need generated image in high resolution but dimension for my editor are in pixel in low resolution.</p>
  
  <p>For example: canvas  has 800px x 600px and I need an final image with 100 cm x 400 cm, in other words, in real size.</p>