In other words, it shouldn’t matter whether you run your apps on an iPhone 11 Pro Max or an iPad 12.9” — either way, it should look good. The same holds true for dynamic content. Whether it’s a single line of text or twenty lines of text, your UI needs to adapt. With an adaptive layout, you can create a visually stunning app on all devices.
Auto Layout helps developers adapt user interface layouts for external and internal changes. Some examples include:
Different screen sizes.
iPadOS multitasking features like Slide Over, Split View and Picture in Picture.
Device rotation.
Larger text support.
Internationalization support.
Dynamic content support.


The superview is the view that contains a child view.
Every view has a superview, and every screen has a view. The standard view of a screen is the view controller’s view. It’s the base layer containing all of the user interfaces on a single screen. You can consider this view as a blank canvas because you can put any drawings on top of it.


An attribute is a view feature Auto Layout uses to create a relationship between two views. There are two types of attributes: location and size. Location attributes include a view’s leading, trailing, top and bottom edges. Size attributes include the view’s width and height. Different user interfaces have different sets of attributes.


A multiplier is a ratio you can apply to a relationship between two item attributes. For example, you can have Label B be twice the height of Label A.


Constant is a fixed value that you add to a constraint. For example, Label A’s leading edge spaces 16 points away from the superview’s leading edge.
For a deep dive into the Auto Layout engine, read Chapter 14, “Under the Hood of Auto Layout.”
There are a few more key concepts that impact how Auto Layout works. These include intrinsic content size and priorities.