NEW: Subscribe to Hacking with Swift+ and accelerate your learning! >>

How to read the red, green, blue, and alpha color components from a UIColor

Swift version: 5.2

Paul Hudson    @twostraws   

Creating a UIColor from red, green, blue, and alpha (RGBA) is easy enough:

let color = UIColor(red: 0.8, green: 0.1, blue: 0.5, alpha: 1)

But when you want to read those values back, you need to do a little more work. UIColor has a built-in method called getRed(), which unpacks the RGBA values into variable floats – you need to create four variables first, then pass them in by reference:

var red: CGFloat = 0
var green: CGFloat = 0
var blue: CGFloat = 0
var alpha: CGFloat = 0

color.getRed(&red, green: &green, blue: &blue, alpha: &alpha)

When that runs, red will have 0.8, green will have 0.1, and so on.

Because this is a pain to use you might find it best to wrap it up in an extension:

extension UIColor {
    var rgba: (red: CGFloat, green: CGFloat, blue: CGFloat, alpha: CGFloat) {
        var red: CGFloat = 0
        var green: CGFloat = 0
        var blue: CGFloat = 0
        var alpha: CGFloat = 0
        getRed(&red, green: &green, blue: &blue, alpha: &alpha)

        return (red, green, blue, alpha)
    }
}

Now you can use color.rgba to get back a tuple of all four color values.

Hacking with Swift is sponsored by Instabug

SPONSORED Are you tired of wasting time debugging your Swift app? Instabug’s SDK is here to help you minimize debugging time by providing you with complete device details, network logs, and reproduction steps with every bug report. All data is attached automatically, and it only takes a line of code to setup. Start your free trial now and get 3 months off exclusively for the Hacking with Swift Community.

Start your free trial!

Sponsor Hacking with Swift and reach the world's largest Swift community!

Available from iOS 5.0

Similar solutions…

About the Swift Knowledge Base

This is part of the Swift Knowledge Base, a free, searchable collection of solutions for common iOS questions.

BUY OUR BOOKS
Buy Pro Swift Buy Swift Design Patterns Buy Testing Swift Buy Hacking with iOS Buy Swift Coding Challenges Buy Swift on Sundays Volume One Buy Server-Side Swift (Vapor Edition) Buy Advanced iOS Volume One Buy Advanced iOS Volume Two Buy Advanced iOS Volume Three Buy Hacking with watchOS Buy Hacking with tvOS Buy Hacking with macOS Buy Dive Into SpriteKit Buy Swift in Sixty Seconds Buy Objective-C for Swift Developers Buy Server-Side Swift (Kitura Edition) Buy Beyond Code

Was this page useful? Let us know!

Average rating: 4.8/5

Link copied to your pasteboard.