NSImage Flip Horizontally (Swift)

gistfile1.txt

        
        public func flipHorizontally() -> IOSXImage {
            let existingImage: NSImage? = self
            let existingSize: NSSize? = existingImage?.size
            let newSize: NSSize? = NSMakeSize((existingSize?.width)!, (existingSize?.height)!)
            let flipedImage = NSImage(size: newSize!)
            flipedImage.lockFocus()
            
            let t = NSAffineTransform.init()
            t.translateX(by: (existingSize?.width)!, yBy: 0.0)
            t.scaleX(by: -1.0, yBy: 1.0)
            t.concat()
            
            let rect:NSRect = NSMakeRect(0, 0, (newSize?.width)!, (newSize?.height)!)
            existingImage?.draw(at: NSZeroPoint, from: rect, operation: .sourceOver, fraction: 1.0)
            flipedImage.unlockFocus()
            return flipedImage
        }