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Generating a random color in SwiftUI

May 25, 2022 swiftuicolors

In this post, we’ll take a quick look at how to generate a random color in SwiftUI, using the nice random api:s provided in Swift.

In Objective-C, random values involved a lot of arc4random_uniform code, which doesn’t read well. You could use these global functions to generate random values, colors etc., often with a lot of code.

As Swift introduced random APIs for various numeric values, these things became way less complicated. However, some types like Color, still don’t have built-in random support.

We can add this support to Color quite easily, by using the Double random capabilities and the rgb Color initializer that was added in iOS 14.

public extension Color {

    static func random(randomOpacity: Bool = false) -> Color {
        Color(
            red: .random(in: 0...1),
            green: .random(in: 0...1),
            blue: .random(in: 0...1),
            opacity: randomOpacity ? .random(in: 0...1) : 1
        )
    }
}

This lets you generate a random color and lets you specify whether you want a random opacity or not.

You can use random colors for various features, as a background color to make view debugging easier etc. since it makes it easy to see which views redraw.

Conclusion

This was a short post, but I hope you found it helpful. You can find the source code in my SwiftUIKit library. Feel free to try it out and let me know what you think.