How to Convert UIImage to CIImage and vice versa

CIImage *ciImage = [UIImage imageNamed:@"test.png"].CIImage;
UIImage *uiImage = [[UIImage alloc] initWithCIImage:ciImage];

To fix the case where myUIImage.CIImage returns nil like [UIImageView image], you can instead do [CIImage imageWithCGImage:myUIImage.CGImage] – Dylan Hand

Swift version:

let ciImage = UIImage(named: "test.png")!.ciImage
let uiImage = UIImage(ciImage: ciImage)

To fix the case where myUIImage.ciImage returns nil like you can instead do CIImage(cgImage: myUIImage!.cgImage!).