title: High Quality Scaling of UIImage
body: <p>I need to scale the resolution of an image coming from a view layer in an iPhone application.  The obvious way is to specify a scale factor in UIGraphicsBeginImageContextWithOptions, but any time the scale factor is not 1.0 then quality of the image goes to pot -- far more than would be expected from the loss of pixels.</p>
  
  <p>I've tried several other scaling techniques, but they all seem to revolve around CGContext stuff and all appear to do the same thing.</p>
  
  <p>Simply changing image "size" (without changing the dot resolution) isn't sufficient, mostly because that info seems to be discarded very quickly by other hands in the pipeline (the image will be converted to a JPG and emailed).</p>
  
  <p>Is there any other way to scale an image on iPhone?</p>