session-ios/SignalMessaging/utils/UIColor+Helper.swift

extension UIColor {
    
    public func adjust(hueBy hue: CGFloat = 0, saturationBy saturation: CGFloat = 0, brightnessBy brightness: CGFloat = 0) -> UIColor {
        
        var currentHue: CGFloat = 0.0
        var currentSaturation: CGFloat = 0.0
        var currentBrigthness: CGFloat = 0.0
        var currentAlpha: CGFloat = 0.0
        
        if getHue(&currentHue, saturation: &currentSaturation, brightness: &currentBrigthness, alpha: &currentAlpha) {
            return UIColor(hue: currentHue + hue,
                           saturation: currentSaturation + saturation,
                           brightness: currentBrigthness + brightness,
                           alpha: currentAlpha)
        } else {
            return self
        }
    }
    
    convenience init(red: Int, green: Int, blue: Int, a: CGFloat = 1.0) {
        self.init(
            red: CGFloat(red) / 255.0,
            green: CGFloat(green) / 255.0,
            blue: CGFloat(blue) / 255.0,
            alpha: a
        )
    }
    
    convenience init(rgb: Int, a: CGFloat = 1.0) {
        self.init(
            red: (rgb >> 16) & 0xFF,
            green: (rgb >> 8) & 0xFF,
            blue: rgb & 0xFF,
            a: a
        )
    }
}