Swift NSImage to CGImage

Question

How can I convert a NSImage to CGImage in Swift? In Objective-C I did it like this:

- (CGImageRef)CGImage {
    NSData *imageData = self.TIFFRepresentation;
         


        

Answer 1

Swift 3 and 4 version code :-

if let image = NSImage(named: "Icon"){
    let cgImage = image.cgImage(forProposedRect: nil, context: nil, hints: nil)
}

Answer 2

Here's what I'm using to convert NSImage to CGImage:

let image = NSImage(named:"image")
if let image = image {
    var imageRect = CGRect(x: 0, y: 0, width: image.size.width, height: image.size.height)
    let imageRef = image.cgImage(forProposedRect: &imageRect, context: nil, hints: nil)
}

Answer 3

Ah, I found the solution. It's because in Swift you only the an unmanaged object (I just did not really understand, what this means). But this code now works:

extension NSImage {
    var CGImage: CGImageRef {
    get {
        let imageData = self.TIFFRepresentation
        let source = CGImageSourceCreateWithData(imageData as CFDataRef, nil).takeUnretainedValue()
        let maskRef = CGImageSourceCreateImageAtIndex(source, UInt(0), nil)
        return maskRef.takeUnretainedValue();
    }
    }
}

Answer 4

For Swift 4.0, XCode 9.2:

extension NSImage {
    @objc var CGImage: CGImage? {
       get {
            guard let imageData = self.tiffRepresentation else { return nil }
            guard let sourceData = CGImageSourceCreateWithData(imageData as CFData, nil) else { return nil }
            return CGImageSourceCreateImageAtIndex(sourceData, 0, nil)
       }
    }
}

Answer 5

A Swift 5 implementation:

extension NSImage {
    var CGImage: CGImage {
        get {
            let imageData = self.tiffRepresentation!
            let source = CGImageSourceCreateWithData(imageData as CFData, nil).unsafelyUnwrapped
            let maskRef = CGImageSourceCreateImageAtIndex(source, Int(0), nil)
            return maskRef.unsafelyUnwrapped
        }
    }
}