How to flip UIImage horizontally with Swift?

Most factory methods are converted to initializers in swift. Whenever available, even if the class method is still available, they are preferred. You can use:

    init(CGImage cgImage: CGImage!, scale: CGFloat, orientation: UIImageOrientation)

The usage would look like this:

var image = UIImage(CGImage: img.CGImage, scale: 1.0, orientation: .DownMirrored)

Swift 5

var image = UIImage(cgImage: img.cgImage!, scale: 1.0, orientation: .downMirrored)

For me the simplest way was to use the .withHorizontallyFlippedOrientation() instance method of UIImage as follows:

let flippedImage = straightImage.withHorizontallyFlippedOrientation()

Simple one-liners always make me happy :)