NSImage class extension method to get the NSColor of the image at the specified (x,y) coordinate.

NSImage Color At Coordinate.swift

public extension NSImage {
    /// Gets the color at the specified coordinate.
    /// - Parameters:
    ///   - x: The horizontal coordinate.
    ///   - y: The vertical coordinate.
    func colorAt(x: Int, y: Int) -> NSColor? {
        if let tiffRep = self.tiffRepresentation {
            if let bitmapRep = NSBitmapImageRep(data: tiffRep) {
                let flippedY = Int(bitmapRep.size.height) - y
                let color = bitmapRep.colorAt(x: x, y: flippedY)
                return color
            }
        }
        return nil
    }
}