space-ios/iOSClient/Media/NCMediaGridLayout.swift

//
//  NCMediaGridLayout.swift
//  Nextcloud
//
//  Created by Marino Faggiana on 27/01/24.
//  Copyright © 2024 Marino Faggiana. All rights reserved.
//
//  Author Marino Faggiana <marino.faggiana@nextcloud.com>
//
//  This program is free software: you can redistribute it and/or modify
//  it under the terms of the GNU General Public License as published by
//  the Free Software Foundation, either version 3 of the License, or
//  (at your option) any later version.
//
//  This program is distributed in the hope that it will be useful,
//  but WITHOUT ANY WARRANTY; without even the implied warranty of
//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//  GNU General Public License for more details.
//
//  You should have received a copy of the GNU General Public License
//  along with this program.  If not, see <http://www.gnu.org/licenses/>.
//

import UIKit

class NCMediaGridLayout: UICollectionViewFlowLayout {

    var marginLeftRight: CGFloat = 2
    var itemForLine: CGFloat = 3

    override init() {
        super.init()

        sectionHeadersPinToVisibleBounds = false

        minimumInteritemSpacing = 0
        minimumLineSpacing = marginLeftRight

        self.scrollDirection = .vertical
        self.sectionInset = UIEdgeInsets(top: 0, left: marginLeftRight, bottom: 0, right: marginLeftRight)
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    override var itemSize: CGSize {
        get {
            if let collectionView = collectionView {

                let itemWidth: CGFloat = (collectionView.frame.width - marginLeftRight * 2 - marginLeftRight * (itemForLine - 1)) / itemForLine
                let itemHeight: CGFloat = itemWidth

                return CGSize(width: itemWidth, height: itemHeight)
            }

            // Default fallback
            return CGSize(width: 100, height: 100)
        }
        set {
            super.itemSize = newValue
        }
    }

    override func targetContentOffset(forProposedContentOffset proposedContentOffset: CGPoint) -> CGPoint {
        return proposedContentOffset
    }
}

extension NCMedia: UICollectionViewDelegateFlowLayout {

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, referenceSizeForHeaderInSection section: Int) -> CGSize {
        return CGSize(width: collectionView.frame.width, height: 0)
    }

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, referenceSizeForFooterInSection section: Int) -> CGSize {
        return CGSize(width: collectionView.frame.width, height: 0)
    }
}