A Swift class with additional functionality for Color. Also shows name spacing techniques for adding non-colliding extensions.

MNGColorExtensions.swift

//
//  MNGColorExtensions.swift
//  
//
//  Created by Tommie N. Carter, Jr., MBA on 8/19/15.
//  Copyright © 2015 MING Technology. All rights reserved.
//
import Foundation

#if os(OSX)
    
    import Cocoa
    public  typealias PXColor = NSColor
    
    #else
    
    import UIKit
    public  typealias PXColor = UIColor
    
#endif

extension PXColor {
    
    func lighter(amount : CGFloat = 0.25) -> PXColor {
        return hueColorWithBrightnessAmount(1 + amount)
    }
    
    func darker(amount : CGFloat = 0.25) -> PXColor {
        return hueColorWithBrightnessAmount(1 - amount)
    }
    
    private func hueColorWithBrightnessAmount(amount: CGFloat) -> PXColor {
        var hue         : CGFloat = 0
        var saturation  : CGFloat = 0
        var brightness  : CGFloat = 0
        var alpha       : CGFloat = 0
        
        #if os(iOS)
            
            if getHue(&hue, saturation: &saturation, brightness: &brightness, alpha: &alpha) {
                return PXColor( hue: hue,
                    saturation: saturation,
                    brightness: brightness * amount,
                    alpha: alpha )
            } else {
                return self
            }
            
            #else
            
            getHue(&hue, saturation: &saturation, brightness: &brightness, alpha: &alpha)
            return PXColor( hue: hue,
                saturation: saturation,
                brightness: brightness * amount,
                alpha: alpha )
            
        #endif
        
    }
    func colorWithHexString (hexStr:String, alpha:Float? = 1.0) -> PXColor {
        var hexInt:UInt32 = 0
        let scanner = NSScanner(string: hexStr)
        scanner.charactersToBeSkipped = NSCharacterSet(charactersInString: "#")
        scanner.scanHexInt(&hexInt)
        
        return
            PXColor(colorLiteralRed: ((Float) ((hexInt & 0xFF0000) >> 16))/255, green: ((Float) ((hexInt & 0xFF00) >> 8))/255, blue: ((Float) (hexInt & 0xFF))/255, alpha:  alpha!)
    }
    func hexStringWithColor (color:PXColor) -> String {
        let components = CGColorGetComponents(color.CGColor)
        let r = Float(components[0])
        let g = Float(components[1])
        let b = Float(components[2])
        
    
        return String(format: "#%02lX%02lX%02lX", lroundf(r * 255),lroundf(g * 255),lroundf(b * 255))
    }
    convenience init(red: Int, green: Int, blue: Int) {
        assert(red >= 0 && red <= 255, "Invalid red component")
        assert(green >= 0 && green <= 255, "Invalid green component")
        assert(blue >= 0 && blue <= 255, "Invalid blue component")
        self.init(red: CGFloat(red) / 255.0, green: CGFloat(green) / 255.0, blue: CGFloat(blue) / 255.0, alpha: 1.0)
    }
    convenience init(netHex:Int) {
        self.init(red:(netHex >> 16) & 0xff, green:(netHex >> 8) & 0xff, blue:netHex & 0xff)
    }
}