Change text color based on the background

TitleColorLabel.swift

class TitleColorLabel: UILabel {
    var lightTitleColor: UIColor = .white { didSet { updateTitleColor() }}
    var darkTitleColor: UIColor = .black { didSet { updateTitleColor() }}
    
    override var backgroundColor: UIColor? {
        didSet {
            updateTitleColor()
        }
    }
    
    func updateTitleColor() {
        textColor = backgroundColor?.isLight() == true ? lightTitleColor : darkTitleColor
    }
}

extension UIColor {
    var isLight: Bool {
        var white: CGFloat = 0
        getWhite(&white, alpha: nil)
        return white > 0.5
    }
}