Swift version: 5.1
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.
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Available from iOS 2.0
This is part of the Swift Knowledge Base, a free, searchable collection of solutions for common iOS questions.