SwiftでCartographyを使う方法

//画面の横幅の長さを取得する変数を宣言
        let width = UIScreen.main.bounds.size.width
//banner画像
        let banner_image:UIImage = UIImage(named:"logo")!
        let imageView = UIImageView(image:banner_image)
        self.view.addSubview(imageView)
        constrain(imageView, view) { banner_image, view in
            banner_image.top == banner_image.superview!.top + 120
            banner_image.left == banner_image.superview!.left + 25
            banner_image.width == width - 50
            banner_image.height == (width - 50) / 2
        }

参考URL

https://wagtechblog.com/programing/swift-cartography.html