Make edges of SKSpriteNode look smooth after rotation

问题

I create a SKSpriteNode like that:

var shape:SKSpriteNode = SKSpriteNode(color: UIColor.redColor(), size: CGSizeMake(CGFloat(sizeOfShape), CGFloat(sizeOfShape)))

How can I achieve, that a SKSpriteNode has still smooth edges, after I've rotated it.

Currently, it looks like that:

As you see, the edges are jagged.

来源：https://stackoverflow.com/questions/25532760/make-edges-of-skspritenode-look-smooth-after-rotation