title: HTML5 Canvas: Zooming
body: <p>Is there any easy way how to zoom in and back out in canvas (JavaScript)? Basically I have a 400x400px canvas and I'd like to be able to zoom in with 'mousedown' (2x) and go back with 'mouseup'.</p>
  
  <p>Spent last two days googling, but no luck so far.  :(</p>