Cats section for https://github.com/yfujiki/CompositionalLayoutSample

CompositionalLayoutSample-CatsSection.swift

func setupCatsSection() -> NSCollectionLayoutSection {
    // 1. Configuring Section. Item -> Group -> Section
    // Item
    let item = NSCollectionLayoutItem(
        layoutSize: NSCollectionLayoutSize(widthDimension: .fractionalWidth(1.0),
                                           heightDimension: .fractionalHeight(1.0)))
    item.contentInsets = NSDirectionalEdgeInsets(top: 6.7, leading: 10.0, bottom: 6.7, trailing: 10.0)

    // Group
    let group = NSCollectionLayoutGroup.vertical(
        layoutSize: NSCollectionLayoutSize(widthDimension: .fractionalWidth(1.0),
                                           heightDimension: .fractionalWidth(0.67)),
        subitem: item,
        count: 1)

    // Section
    let section = NSCollectionLayoutSection(group: group)
    section.contentInsets = NSDirectionalEdgeInsets(top: 16.0,
                                                    leading: 0.0,
                                                    bottom: 16.0,
                                                    trailing: 0.0)

    // 2. Header
    section.boundarySupplementaryItems = [headerViewSupplementaryItem]

    return section
}