Get the correct image width and height of an NSImage

Question

I use the code below to get the width and height of a NSImage:

NSImage *image = [[[NSImage alloc] initWithContentsOfFile:[NSString stringWithFormat:s]] autorelea         


        

Answer 1

SWIFT 4

You have to make a NSBitmapImageRep representation of the NSImage to get the correct pixel height and width. First a this extension to gather a CGImage from the NSImage:

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)
        }
    }
}

Then when you want to get the height and width:

let rep = NSBitmapImageRep(cgImage: (NSImage(named: "Your Image Name")?.CGImage)!)
let imageHeight = rep.size.height
let imageWidth = rep.size.width