simularWordSizes for WordCloudView

simularWordSizes.swift

func simularWordSizes(a: [CGSize], b: [CGSize]) -> Bool {
    if a == b {
        return true
    }
    
    if a.count != b.count {
        return false
    }
    var diff : CGFloat = 0
    for i in 0...(a.count-1) {
        diff += abs(a[i].width - b[i].width) +
        abs(a[i].height - b[i].height)
    }
    
    return diff < 0.01
}

func calcPositions(canvasSize: CGSize, itemSizes: [CGSize]) -> [CGPoint] {
    // ...
    
    if positionCache.canvasSize == canvasSize
        && simularWordSizes(a: positionCache.wordSizes, b: wordSizes) {
        return positionCache.positions
    }
    
    // ...
}