Possible Duplicate:
How to do antialiasing on a rotated view?
I'm trying to rotate some UIImageViews using this technique:
imageView.transform = CGAffineTransformMakeRotation(r);
where r is a float usually between -0.3 and 0.3.
The problem is that the images (which are derived from square jpegs) that are rotated have jagged edges (pixellation), because they are at an angle after the transform. Is there a way to fix this so the edges are smooth (i.e. antialiased)?
There is a key that you can set in Info.plist that enables antialiasing of the edges: UIViewEdgeAntialiasing.
来源：https://stackoverflow.com/questions/7080325/when-i-rotate-an-uiimageview-with-the-transform-property-the-edges-pixellate