NEW: Master Swift design patterns with my latest book! >>

How to create custom colors using UIColor RGB and hues

Written by Paul Hudson    @twostraws

Although there are quite a few built-in UIColors, you'll want to create your own very frequently. This can be done in a number of ways, but the most common is specifying individual values for red, green, blue and alpha, like this:

let col1 = UIColor(red: 1, green: 0, blue: 0, alpha: 1)

Each of those numbers need to be between 0 and 1.

An alternative way is to specify color values as hue, saturation and brightness, or HSB. Hue is a value between 0 and 1 on a color wheel, where 0 and 1 are both red. Saturation is how deep the color should be (so 0 is just gray) and brightness is how light the shade should be.

Here's how it's done:

let col2 = UIColor(hue: 0, saturation: 0.66, brightness: 0.66, alpha: 1)
let col3 = UIColor(hue: 0.25, saturation: 0.66, brightness: 0.66, alpha: 1)
let col4 = UIColor(hue: 0.5, saturation: 0.66, brightness: 0.66, alpha: 1)
let col5 = UIColor(hue: 0.75, saturation: 0.66, brightness: 0.66, alpha: 1)

The advantage to using HSB rather than RGB is that you can generate very similar colors by keeping the saturation and brightness constant and changing only the hue – the code above generates some nice pastel shades of red, green, cyan and magenta, for example.

Available from iOS 2.0

Did this solution work for you? Please pass it on!

Other people are reading…

About the Swift Knowledge Base

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

Test your Swift today

Think you know Swift? My book Swift Coding Challenges will put your Swift skills to the test – it's perfect for job interviews and more!

Click here to visit the Hacking with Swift store >>