Get lighter and darker color variations for a given UIColor

Question

How to get different lighter and darker variations of a given UIColor in Swift?

Answer 1

Since I use SwiftUI in my current project, I adapted the best answer from Stephen. Tested with Xcode 12.0, SwiftUI 2 and iOS 14.0

extension Color {
    var components: (red: CGFloat, green: CGFloat, blue: CGFloat, opacity: CGFloat) {
        #if canImport(UIKit)
        typealias NativeColor = UIColor
        #elseif canImport(AppKit)
        typealias NativeColor = NSColor
        #endif

        var r: CGFloat = 0
        var g: CGFloat = 0
        var b: CGFloat = 0
        var o: CGFloat = 0

        guard NativeColor(self).getRed(&r, green: &g, blue: &b, alpha: &o) else {
            return (0, 0, 0, 0)
        }
        return (r, g, b, o)
    }
    
    func lighter(by percentage: CGFloat = 30.0) -> Color {
        return self.adjust(by: abs(percentage) )
    }

    func darker(by percentage: CGFloat = 30.0) -> Color {
        return self.adjust(by: -1 * abs(percentage) )
    }

    func adjust(by percentage: CGFloat = 30.0) -> Color {
        return Color(red: min(Double(self.components.red + percentage/100), 1.0),
                     green: min(Double(self.components.green + percentage/100), 1.0),
                     blue: min(Double(self.components.blue + percentage/100), 1.0),
                     opacity: Double(self.components.opacity))
    }
}