DSSCollectionViewFlowLayout - A UICollectionViewFlow that will equally space UICollectionView Cells

DSSCollectionViewFlowLayout.swift

//
//  DSSCollectionViewFlowLayout.swift
//
//  Created by Gary L. Wade on 9/5/16. Adapted by Rob Lester on 5/2/18.
//  Copyright © 2018 Gary L. Wade. All rights reserved.
//  Original: https://medium.com/@garywade/equally-spacing-uicollectionview-cells-6d74401f8f56
//
//  Tested On: Xcode 9.3 / Swift 4.1
//

import UIKit

@objc(DSSCollectionViewFlowLayout)
class DSSCollectionViewFlowLayout: UICollectionViewFlowLayout {
    override func prepare () {
        super.prepare()

        var contentByItems: ldiv_t

        let contentSize = self.collectionViewContentSize
        let itemSize = self.itemSize

        if UICollectionViewScrollDirection.vertical == self.scrollDirection {
            contentByItems = ldiv (Int(contentSize.width), Int(itemSize.width))
        } else {
            contentByItems = ldiv (Int(contentSize.height), Int(itemSize.height))
        }

        let layoutSpacingValue = CGFloat(NSInteger (CGFloat(contentByItems.rem))) / CGFloat (contentByItems.quot + 1)

        let originalMinimumLineSpacing = self.minimumLineSpacing
        let originalMinimumInteritemSpacing = self.minimumInteritemSpacing
        let originalSectionInset = self.sectionInset

        if layoutSpacingValue != originalMinimumLineSpacing ||
            layoutSpacingValue != originalMinimumInteritemSpacing ||
            layoutSpacingValue != originalSectionInset.left ||
            layoutSpacingValue != originalSectionInset.right ||
            layoutSpacingValue != originalSectionInset.top ||
            layoutSpacingValue != originalSectionInset.bottom {

            let insetsForItem = UIEdgeInsets.init(top: layoutSpacingValue, left: layoutSpacingValue, bottom: layoutSpacingValue, right: layoutSpacingValue)

            self.minimumLineSpacing = layoutSpacingValue
            self.minimumInteritemSpacing = layoutSpacingValue
            self.sectionInset = insetsForItem
        }
    }
}