Struct FlowLayout

Sources/Fluid/UI/SettingsView.swift:2740–2812

// MARK: - Flow Layout

struct FlowLayout: Layout {
    struct Cache {
        var sizes: [CGSize] = []
        var positions: [CGPoint] = []
        var containerSize: CGSize = .zero
        var lastWidth: CGFloat = 0
    }

    var spacing: CGFloat = 8

    func makeCache(subviews: Subviews) -> Cache {
        Cache(sizes: Array(repeating: .zero, count: subviews.count))
    }

    func sizeThatFits(proposal: ProposedViewSize, subviews: Subviews, cache: inout Cache) -> CGSize {
        self.arrangeSubviews(proposal: proposal, subviews: subviews, cache: &cache)
        return cache.containerSize
    }

    func placeSubviews(in bounds: CGRect, proposal: ProposedViewSize, subviews: Subviews, cache: inout Cache) {
        self.arrangeSubviews(proposal: proposal, subviews: subviews, cache: &cache)
        for (index, position) in cache.positions.enumerated() {
            subviews[index].place(
                at: CGPoint(x: bounds.minX + position.x, y: bounds.minY + position.y),
                proposal: .unspecified
            )
        }
    }

    private func arrangeSubviews(
        proposal: ProposedViewSize,
        subviews: Subviews,
        cache: inout Cache
    ) {
        let proposedWidth = proposal.width ?? 0
        let maxWidth = proposedWidth > 0 ? proposedWidth : 260
        let needsLayout = cache.positions.count != subviews.count || cache.lastWidth != maxWidth

        if needsLayout {
            cache.positions = []
            cache.positions.reserveCapacity(subviews.count)
            cache.sizes = Array(repeating: .zero, count: subviews.count)
        }

        var x: CGFloat = 0
        var y: CGFloat = 0
        var rowHeight: CGFloat = 0

        for index in subviews.indices {
            let size: CGSize
            if needsLayout {
                size = subviews[index].sizeThatFits(.unspecified)
                cache.sizes[index] = size
            } else {
                size = cache.sizes[index]
            }

            if x + size.width > maxWidth, x > 0 {