iOS UIImageView vs drawRect image stretching
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I was looking at a WWDC video from 2011 about UIKit rendering and there is this section which speaks how UIImageView is more efficient than using drawRect. Here is an example the session shows:


![enter image description here][1]


  [1]: http://i.stack.imgur.com/XowFV.jpg

I am not so clear on why stretching an image to 320x200 would take 250 additional Kbs using drawRect but not using UIImageView? Wouldn't UIImageView need the same number of additional pixels to resize and render the image?

Can someone please explain?