swift 5.0 本地随机验证码文本校验效果。

//
//  qshdVerifyCodeView.swift
//  qshd
//
//  Created by 钟高荣 on 2020/3/12.
//  Copyright © 2020 钟高荣. All rights reserved.
//

import UIKit

class qshdVerifyCodeView: UIView {
    
    // 验证码的位数
    let charCount = 4
    // 混淆的横线个数
    let lineCount = 5
    // 随机产生的字符串， 由上级界面产生。
    var verifyStr:String? {
        didSet {
            guard verifyStr != nil  else {
                return
            }
            self.setNeedsDisplay()
        }
    }
    
    // MARK: - 重写init方法
    override init(frame: CGRect) {
        super.init(frame: frame)
        self.layer.cornerRadius = 5.0
        self.layer.masksToBounds = true
        self.backgroundColor = UIColor.muColor(.whiteGray)
    }
    
    // MARK: - 重写点击方法重新获取
    override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
       // 暂未用到
    }
    
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    //  根据输入的数组获取 0-x 的随机数
    func ranNum(num:Int)->Int {
        let ranNum = arc4random()%UInt32(num)
        return Int(ranNum)
    }
    
    override func draw(_ rect: CGRect) {
        super.draw(rect)
        let ctx = UIGraphicsGetCurrentContext()//获取当前上下文
        //2转换坐标
        ctx?.textMatrix = CGAffineTransform.identity
        ctx?.translateBy(x: 0, y: self.bounds.size.height)
        ctx?.scaleBy(x: 1.0, y: -1.0)
        
        // 获取每个字符需要的宽度
        let width = (CGFloat)(Int(self.frame.size.width) / self.charCount)
        let height = self.frame.size.height
        
        //生成path
        let pathText = CGMutablePath()
        pathText.addRect(self.bounds)
        
        // 绘制每一个字
        for (index,text) in  self.verifyStr!.enumerated(){
            // 随机x位置
            let pX = CGFloat(CGFloat(index) * width + CGFloat(self.ranNum(num: Int(width)) / 2))
            // 随机y位置
            let pY = CGFloat(self.ranNum(num: 5) - self.ranNum(num: 5))
            // 文字大小
            let font = UIFont.systemFont(ofSize: 22)

            let path1 = UIBezierPath(roundedRect: CGRect.init(x: pX, y: pY, width: width, height: height), cornerRadius: 0).cgPath
            
            let str = String.init(text)
            let mutableAttrStr = NSMutableAttributedString(string: str)
            mutableAttrStr.addAttributes([NSAttributedString.Key.font:font, NSAttributedString.Key.foregroundColor:UIColor.randomColor], range: NSMakeRange(0, 1))
            
            let frameSetter = CTFramesetterCreateWithAttributedString(mutableAttrStr)
                let frame = CTFramesetterCreateFrame(frameSetter, CFRangeMake(0, mutableAttrStr.length), path1, nil)
                
            //绘制文本
            CTFrameDraw(frame, ctx!)
        }
        
        // 绘制干扰线
        for _ in 0..<lineCount {
             
            let path = UIBezierPath()
            
            var pX:CGFloat = 0.0
            var pY:CGFloat = 0.0
            // 起点
            pX = CGFloat(self.ranNum(num: Int(rect.size.width)))
            pY = CGFloat(self.ranNum(num: Int(rect.size.height)))
            path.move(to: CGPoint(x: pX, y: pY))
            // 终点
            let ppX = CGFloat(self.ranNum(num: Int(rect.size.width)))
            let ppY = CGFloat(self.ranNum(num: Int(rect.size.height)))
            path.addLine(to: CGPoint.init(x: ppX, y: ppY))
            path.close()
            // 随机线颜色
            let color = UIColor.randomColor
            color.setStroke()
            color.setFill()
            path.lineWidth = FMPx(1)
            path.stroke()
        }
    }
}

效果如下