title: CIContext drawImage:inRect:fromRect: scaling
body: <p>I am using <code>CIContext</code> method <code>- (void)drawImage:(CIImage *)im inRect:(CGRect)dest fromRect:(CGRect)src</code> to draw my image to screen. But I need to implement zoom-in/zoom-out method. How could I achieve it? I think zoom-in could be achieved increasing <code>dest</code> rect, because apple docs says:</p>
  
  <pre><code>The image is scaled to fill the destination rectangle.
  </code></pre>
  
  <p>But what about zoom-out? Because if <code>dest</code> rectangle is scaled down, then image is drawn in it's actual size, but only part of image is visible then (part that fits in <code>dest</code> rectangle). </p>
  
  <p>What could you suggest?</p>