iOS 生成图片验证码(实用功能)

for index in 0..<4 {
      let i = (Int)(arc4random()) % (codeArray.count-1)
      let str = codeArray[i]
      if index == 0 {
        codeStr = str as NSString
      }else {
        codeStr = "\(codeStr)\(str)" as NSString
      }
    }

for i in 0..<codeStr.length {
      let pxx = arc4random() % UInt32(randWidth)
      let px = CGFloat(pxx) + CGFloat(i)*(self.frame.size.width-3)/CGFloat(codeStr.length)
      let py = arc4random() % UInt32(randHeight)
      let label = UILabel.init(frame: CGRect.init(x: px + 3, y: CGFloat(py), width: textSize.width, height: textSize.height))
      label.text = String.init(format: "%C", codeStr.character(at: i))
      label.font = UIFont.systemFont(ofSize: 20)
      if (isRotation == true) {
        let a = arc4random() % UInt32(60)
        let r = Double(a)-30
        label.transform = CGAffineTransform.init(rotationAngle: CGFloat(r*M_PI)/180)
      }
      bgView.addSubview(label)
    }

for _ in 0...9 {
      let path = UIBezierPath.init()
      let pX = arc4random() % UInt32(self.frame.width)
      let pY = arc4random() % UInt32(self.frame.height)
      path.move(to: CGPoint.init(x: CGFloat(pX), y: CGFloat(pY)))
      let ptX = arc4random() % UInt32(self.frame.width)
      let ptY = arc4random() % UInt32(self.frame.height)
      path.addLine(to: CGPoint.init(x: CGFloat(ptX), y: CGFloat(ptY)))
      let layer = CAShapeLayer.init()
      layer.strokeColor = UIColor.getRandomColor(withAlpha: 0.2).cgColor//layer的边框色
      layer.lineWidth = 1.0
      layer.strokeEnd = 1
      layer.fillColor = UIColor.clear.cgColor
      layer.path = path.cgPath
      bgView.layer.addSublayer(layer)
    }

public func refreshCode(callBack: @escaping (_ str: NSString) -> ()) {
    initCodeView()
    callBack(codeStr)
  }