How to make a background image run under the safe area

Swift version: 5.10

Paul Hudson @twostraws May 28th 2019

Broadly speaking it’s important to place your views so they are inside the safe area layout guide, but there are some occasions when you want to ignore that and have some that run under the safe area. Apple’s Weather app, for example, goes edge to edge with background weather graphics, then places the important content inside the safe area.

This is easy enough to accomplish: just make sure your background view goes edge to edge using your main view’s leading, trailing, top, and bottom anchors, then use the safe area layout guide’s anchors for your foreground view.

Here’s how that looks in code:

let background = UIView()
background.translatesAutoresizingMaskIntoConstraints = false
background.backgroundColor = .red
view.addSubview(background)

let foreground = UIView()
foreground.translatesAutoresizingMaskIntoConstraints = false
foreground.backgroundColor = .blue
view.addSubview(foreground)

background.leadingAnchor.constraint(equalTo: view.leadingAnchor).isActive = true
background.trailingAnchor.constraint(equalTo: view.trailingAnchor).isActive = true
background.topAnchor.constraint(equalTo: view.topAnchor).isActive = true
background.bottomAnchor.constraint(equalTo: view.bottomAnchor).isActive = true

foreground.leadingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.leadingAnchor).isActive = true
foreground.trailingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.trailingAnchor).isActive = true
foreground.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor).isActive = true
foreground.bottomAnchor.constraint(equalTo: view.safeAreaLayoutGuide.bottomAnchor).isActive = true