swift 计算tag有多少行

import UIKit

var str = "Hello, playground"

let arr:[CGFloat] = [2, 5, 3, 6, 4, 3, 2]

let a:CGFloat = 8

var newArr: [[CGFloat]] = []

let b:[CGFloat] = [2]
newArr.append(b)

var iterator = arr.makeIterator()
var next = iterator.next()
next = iterator.next()
while next != nil {
    guard let value = next else { break }
    if var arr = newArr.last {
        let sum = arr.reduce(value, +)
        print(sum)
        if sum >= 8 {
            print("value: \(value)")
            var newA: [CGFloat] = []
            newA.append(value)
            newArr.append(newA)
        } else {
            arr.append(value)
            newArr[newArr.count - 1] = arr
        }
    }
    
    next = iterator.next()
}

print(newArr)

struct TagCalculation<T: FloatingPoint> {
    
    let widths: [T]
    let maxWidth: T
    
    init(widths: [T], maxWidth: T) {
        self.widths = widths
        self.maxWidth = maxWidth
    }
    
    func getRows() -> Int {
        let arr = widths

        let a = maxWidth

        var newArr: [[T]] = []

        let b = [widths[0]]
        newArr.append(b)

        var iterator = arr.makeIterator()
        var next = iterator.next()
        next = iterator.next()
        while next != nil {
            guard let value = next else { break }
            if var arr = newArr.last {
                let sum = arr.reduce(value, +)
                print(sum)
                if sum >= a {
                    print("value: \(value)")
                    var newA: [T] = []
                    newA.append(value)
                    newArr.append(newA)
                } else {
                    arr.append(value)
                    newArr[newArr.count - 1] = arr
                }
            }
            
            next = iterator.next()
        }

        print(newArr)
        return newArr.count
    }
}

let c = TagCalculation(widths: arr, maxWidth: a)

c.getRows()

增加了gap，2个label间距，需要注意gap，是否算对了。如果用了marginlabel，记得把marginlabel中margin也加上。

struct TagCalculation<T: FloatingPoint> {
    
    let widths: [T]
    let maxWidth: T
    let gap: T
    
    init(widths: [T], maxWidth: T, gap: T) {
        self.widths = widths
        self.maxWidth = maxWidth
        self.gap = gap
    }
    
    func getRows() -> [[T]] {
        let arr = widths
        
        guard arr.count > 0 else { return [] }

        let a = maxWidth

        var newArr: [[T]] = []

        let b = [widths[0]]
        newArr.append(b)

        var iterator = arr.makeIterator()
        var next = iterator.next()
        next = iterator.next()
        while next != nil {
            guard let value = next else { break }
            if var arr = newArr.last {
                let sum = arr.reduce(value) { (result, new) -> T in
                    return result + new + gap
                }
                if sum >= a {
                    var newA: [T] = []
                    newA.append(value)
                    newArr.append(newA)
                } else {
                    arr.append(value)
                    newArr[newArr.count - 1] = arr
                }
            }
            
            next = iterator.next()
        }

        return newArr
    }
}