How to scale up an UIImage without smoothening anything?

#import <QuartzCore/CALayer.h>

view.layer.magnificationFilter = kCAFilterNearest

When drawing directly into bitmap context, we can use:

CGContextSetInterpolationQuality(myBitmapContext, kCGInterpolationNone);

I found this on CGContextDrawImage very slow on iPhone 4

Swift 5

let image = UIImage(named: "Foo")
let scaledImageSize = image.size.applying(CGAffineTransform(scaleX: 2, y: 2))

UIGraphicsBeginImageContext(scaledImageSize)
let scaledContext = UIGraphicsGetCurrentContext()!
scaledContext.interpolationQuality = .none
image.draw(in: CGRect(origin: .zero, size: scaledImageSize))
let scaledImage = UIGraphicsGetImageFromCurrentImageContext()!