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Fold animation in UICollectionViewLayout
I want to achieve Fold animation when the user scrolls UICollectionView. I have UICollectionView with full-screen size cell and vertically scrolling with paging enabled. For that I've created sub-class of UICollectionViewFlowLayout which is as described below. class FoldingFlowLayout: UICollectionViewFlowLayout { private let logger = Logger(subsystem: bundleIdentifier, category: "FlowLayout") override func prepare() { super.prepare() scrollDirection = .vertical minimumLineSpacing = 0 minimumInteritemSpacing = 0 } override func layoutAttributesForElements(in rect: CGRect) -> [UICollectionViewLayoutAttributes]? { let attributes = super.layoutAttributesForElements(in: rect) attributes?.forEach { attribute in transformLayoutAttributes(attribute) } return attributes } override func shouldInvalidateLayout(forBoundsChange newBounds: CGRect) -> Bool { return true } private func transformLayoutAttributes(_ attributes: UICollectionViewLayoutAttributes) { guard let collectionView = collectionView else { return } let contentOffsetY = collectionView.contentOffset.y let cellOffsetY = attributes.frame.origin.y - contentOffsetY let cellHeight = attributes.frame.height var transform = CATransform3DIdentity transform.m34 = -1.0 / 500.0 // Apply perspective if cellOffsetY < cellHeight && cellOffsetY > -cellHeight { let angle = (cellOffsetY / cellHeight) * .pi / 2 transform = CATransform3DRotate(transform, angle, -1, 0, 0) attributes.transform3D = transform attributes.alpha = 1.0 - (abs(cellOffsetY) / cellHeight) } else { attributes.transform3D = CATransform3DIdentity attributes.alpha = 1.0 } } } But this is not working as I expected. I want to create replica of this kind of animation. What am I missing here?
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Jul ’24