Auto Layout Tool Usage In Xcode | iOS Programmer Guide

To help you use views to create a versatile interface, Xcode offers a tool called Auto Layout. Auto Layout is a system for expressing relationships between views in your app’s user interface. Auto Layout lets you define these relationships in terms of constraints on individual views or between sets of views.

The Auto Layout menu, which resides in the bottom-right area of your canvas, has four segments. You use this menu to add various types of constraints to views on your canvas, resolve layout issues, and determine constraint resizing behavior.