How to pixelize and unpixelize an UIImage or UIImageview? - ios

Question

I would like to pixelize and unpixelize an UIImage or an UIImageview using Swift but I have no idea on how can I do that.
Maybe using effects, layer or something like that?

Answer 1

This is a very easy task on iOS.
Pixelation
Your can use the CIPixellate Core Image Filter.
func pixellated(image: UIImage) -> UIImage? {
guard let
ciImage = CIImage(image: image),
filter = CIFilter(name: "CIPixellate") else { return nil }
filter.setValue(ciImage, forKey: "inputImage")
guard let output = filter.outputImage else { return nil }
return UIImage(CIImage: output)
}
Result
The default inputScale value is 8. However you can increase or decrease the effect manually setting the parameter.
filter.setValue(8, forKey: "inputScale")
// ^
// change this
Extension
You can also define the following extension
extension UIImage {
func pixellated(scale: Int = 8) -> UIImage? {
guard let
ciImage = UIKit.CIImage(image: self),
filter = CIFilter(name: "CIPixellate") else { return nil }
filter.setValue(ciImage, forKey: "inputImage")
filter.setValue(scale, forKey: "inputScale")
guard let output = filter.outputImage else { return nil }
return UIImage(CIImage: output)
}
}
Unpixelation
The mechanism is exactly the same, you just need to use a different filter. You can find the full list of filters here (but take a look at which params are available/required for each filter). I think the CIGaussianBlur can do the job.
Of course don't expect to be able to input a low resolution superpixellated image and get an high definition one. This technology is available only in X-Files :D
The Mushroom image has been taken from here.