IBPCollectionViewCompositionalLayout

At the WWDC 2019, Apple introduced a new form of UICollectionViewLayout. A new UICollectionViewCompositionalLayout class has been added to UIKit to make it easier to create compositional layouts without requiring a custom UICollectionViewLayout.

In iOS 12 and earlier, we need subclassing of UICollectionViewLayout to do that. We have to override lots of methods correctly, and it is error-prone.

With Collection View Compositional Layouts, you can make very complex layout even nested collection views with independently scrolling sections just within few lines of code.

Features:

•  Inter Item Spacing
•  Inter Group Spacing
•  Inter Section Spacing
•  Fixed Spacing
•  Flexible Spacing
•  Nested Groups
•  Vertical Scrolling
•  Horizontal Scrolling
•  Supplemental Views (e.g. Section Header/Footers)
•  Pinned Section Header/Footers
•  Decoration Views (e.g. Background Views)
•  Orthogonal Scrolling
•  Orthogonal Scrolling Behavior
•  Estimated Size (Autosizing)
•  Custom Group Item (Absolute Positions)
•  Drop-in replacement