混淆的驗證碼視圖，是我們日常經常用到的功能模塊之一，一般來說后臺不會直接返回我們驗證碼的圖片，一般需要我們將字符串信息轉換成我們需要的視圖；不管是轉換成View還是button，這里介紹一個比較簡單的方法，重寫

override func draw(_ rect: CGRect) 

這里一般需要兩個步驟，一是重寫字符串的字體大小、顏色、樣式等
首先計算每個字符顯示的位置

  let text :String = String.init(format: "\(self.verifyCode)")

        let cSize: CGSize = "A".size(attributes: [NSFontAttributeName: UIFont.systemFont(ofSize: 20)])
        let width = rect.size.width/CGFloat(text.characters.count) - cSize.width
        let hight = rect.size.height - cSize.height
        

設置字符串的字體大小、顏色

  for index in 0..<text.characters.count {
            pX = CGFloat(arc4random()%UInt32(width)) + rect.size.width/CGFloat(text.characters.count)*CGFloat(index)
            pY = CGFloat(arc4random()%UInt32(hight))
            point = CGPoint(x: pX!, y: pY!)
            let c = text.index(text.startIndex, offsetBy: index)
            let textC :String = String.init(format: "%C", c as! CVarArg)
            let randomFont = UIFont.systemFont(ofSize:CGFloat(arc4random()%5+15))
            textC.draw(at: point!, withAttributes: [NSFontAttributeName:randomFont])

            
        }

當然這樣還是完全不夠的，還需要我們繪制干擾線

    let context = UIGraphicsGetCurrentContext()
        context!.setLineWidth(CGFloat(kLineWith));
        
        for _ in 0..<kLineCount {
            let randomCorlor = UIColor.init(colorLiteralRed: Float(arc4random()%255)/Float(255.0), green: Float(arc4random()%255)/Float(255.0), blue: Float(arc4random()%255)/Float(255.0), alpha: 1.0)
            context?.setStrokeColor(randomCorlor.cgColor)
            //起點
            pX = CGFloat(arc4random()%UInt32(rect.size.width))
            pY = CGFloat(arc4random()%UInt32(rect.size.height))
            context?.move(to: CGPoint(x: pX!, y: pY!))
            //終點
            pX = CGFloat(arc4random()%UInt32(rect.size.width))
            pY = CGFloat(arc4random()%UInt32(rect.size.height))
            context?.addLine(to: CGPoint(x: pX!, y: pY!))
            context?.strokePath();
            
        }