Additions to UIColor that allow for easier manipulation of RGBA and HSBA values, in Swift

UIColor+Additions.swift

import UIKit

extension UIColor {
    
    struct HSBA {
        var hue: CGFloat
        var saturation: CGFloat
        var brightness: CGFloat
        var alpha: CGFloat
        
        init(hue: CGFloat = 0.0, saturation: CGFloat = 0.0, brightness: CGFloat = 0.0, alpha: CGFloat = 0.0) {
            self.hue = hue
            self.saturation = saturation
            self.brightness = brightness
            self.alpha = alpha
        }
        
        init?(color: UIColor) {
            var values = HSBA()
            
            guard color.getHue(&values.hue, saturation: &values.saturation, brightness: &values.brightness, alpha: &values.alpha) else {
                return nil
            }
            
            self = values
        }
    }
    
    
    struct RGBA {
        var red: CGFloat
        var green: CGFloat
        var blue: CGFloat
        var alpha: CGFloat
        
        init(red: CGFloat = 0.0, green: CGFloat = 0.0, blue: CGFloat = 0.0, alpha: CGFloat = 0.0) {
            self.red = red
            self.blue = blue
            self.green = green
            self.alpha = alpha
        }
        
        init?(color: UIColor) {
            var values = RGBA()
            
            guard color.getRed(&values.red, green: &values.green, blue: &values.blue, alpha: &values.alpha) else {
                return nil
            }
            
            self = values
        }
    }
    
    
    // MARK: - Public
    
    var hsba: HSBA? {
        return HSBA(color: self)
    }
    
    
    var rgba: RGBA? {
        return RGBA(color: self)
    }
    
    
    // Some inspiration: https://stackoverflow.com/questions/11598043/get-slightly-lighter-and-darker-color-from-uicolor
    
    func colorByAlteringHSBA(_ body: (inout HSBA) -> Void) -> UIColor {
        guard var values = hsba else {
            return self
        }
        
        body(&values)
        return UIColor(hue: values.hue, saturation: values.saturation, brightness: values.brightness, alpha: values.alpha)
    }
    
    
    func colorByAlteringRGBA(_ body: (inout RGBA) -> Void) -> UIColor {
        guard var values = rgba else {
            return self
        }
        
        body(&values)
        return UIColor(red: values.red, green: values.green, blue: values.blue, alpha: values.alpha)
    }
    
    
    
    // MARK: - Helpers
    
    var lightened: UIColor {
        return lighten(by: 0.3)
    }
    
    func lighten(by percent: CGFloat) -> UIColor {
        return colorByAlteringHSBA { values in
            values.brightness = min(values.brightness * (1.0 + percent), 1.0)
        }
    }
    
    
    var darkened: UIColor {
        return darken(by: 0.3)
    }
    
    func darken(by percent: CGFloat) -> UIColor {
        return colorByAlteringHSBA { values in
            values.brightness = max(values.brightness * (1.0 - percent), 0.0)
        }
    }
}