WordCloudStateCache for WordCloudView

WordCloudPositionCache.swift

private var positionCache = WordCloudPositionCache()

func calcPositions(canvasSize: CGSize, itemSizes: [CGSize]) -> [CGPoint] {
    var pos = [CGPoint](repeating: CGPoint.zero, count: itemSizes.count)
    if canvasSize.height == 0 {
        return pos
    }
    
    if positionCache.canvasSize == canvasSize {
        return positionCache.positions
    }
    defer {
        positionCache.canvasSize = canvasSize
        positionCache.wordSizes = wordSizes
        positionCache.positions = pos
    }}
    // ...
}

class WordCloudPositionCache {
    var canvasSize = CGSize.zero
    var wordSizes = [CGSize]()
    var positions = [CGPoint]()
}