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

How to make a UIView glow using shadowColor

Written by Paul Hudson    @twostraws

All views can have shadows thanks to the CALayer behind them, but you can use that same property to create glow effects. For example, this creates a 128x128 view then gives it a 20-point yellow glow:

let vw = UIView(frame: CGRect(x: 100, y: 100, width: 128, height: 128))
vw.backgroundColor = .white

vw.layer.shadowOffset = .zero
vw.layer.shadowColor = UIColor.yellow.cgColor
vw.layer.shadowRadius = 20
vw.layer.shadowOpacity = 1
vw.layer.shadowPath = UIBezierPath(rect: vw.bounds).cgPath

Bright glows work best on a dark background, so try making your main view black:

view.backgroundColor = .black

Available from iOS 3.2

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.

Download for free!

Want a free 75-minute video teaching functional programming, protocol-oriented programming, and more? This is your lucky day!

Click here to visit the Hacking with Swift store >>