NSView extension: insetSubview(_:dx:dy:)

gistfile1.swift

extension NSView {
    
    func insetSubview(subview: NSView, dx: CGFloat, dy: CGFloat) {
        addSubview(subview)
        subview.translatesAutoresizingMaskIntoConstraints = false
        let constrain = { (attribute: NSLayoutAttribute, constant: CGFloat) in
            subview.addConstraint(NSLayoutConstraint(
                item: subview,
                attribute: attribute,
                relatedBy: .Equal,
                toItem: self,
                attribute: attribute,
                multiplier: 1.0,
                constant: constant))
        }
        constrain(.Left, dx)
        constrain(.Right, dx)
        constrain(.Top, dy)
        constrain(.Bottom, dy)
    }
    
}