Swift 3.0 生成二维码图片

二维码的生成其实不复杂，苹果为我们提供了 CoreImage类库，我们可以用它来生成二维码。

import UIKit

class MineViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        //不带图片的二维码图片
        let imageViewIcon1 = UIImageView(frame:CGRect(x: 20, y: 100, width: 100, height: 100))
        imageViewIcon1.image = createQRForString(qrString: "https://www.baidu.com", qrImageName: "")
        self.view.addSubview(imageViewIcon1)

        //带图片的二维码图片
        let imageViewIcon2 = UIImageView(frame: CGRect(x: 200, y: 100, width: 100, height: 100))
        imageViewIcon2.image = createQRForString(qrString: "https://www.baidu.com", qrImageName: "wechat_72x72")
        self.view.addSubview(imageViewIcon2)

    }

    func createQRForString(qrString: String?, qrImageName: String?) -> UIImage?{
        if let sureQRString = qrString{
            let stringData = sureQRString.data(using: String.Encoding.utf8, allowLossyConversion: false)
            //创建一个二维码的滤镜
            let qrFilter = CIFilter(name: "CIQRCodeGenerator")
            qrFilter?.setValue(stringData, forKey: "inputMessage")
            qrFilter?.setValue("H", forKey: "inputCorrectionLevel")
            let qrCIImage = qrFilter?.outputImage

            // 创建一个颜色滤镜,黑白色
            let colorFilter = CIFilter(name: "CIFalseColor")!
            colorFilter.setDefaults()
            colorFilter.setValue(qrCIImage, forKey: "inputImage")
            colorFilter.setValue(CIColor(red: 0, green: 0, blue: 0), forKey: "inputColor0")
            colorFilter.setValue(CIColor(red: 1, green: 1, blue: 1), forKey: "inputColor1")
            // 返回二维码image
            let codeImage = UIImage(ciImage: (colorFilter.outputImage!.applying(CGAffineTransform(scaleX: 5, y: 5))))

            // 中间一般放logo
            if let iconImage = UIImage(named: qrImageName!) {
                let rect = CGRect(x: 0, y: 0, width: codeImage.size.width, height: codeImage.size.height)

                UIGraphicsBeginImageContext(rect.size)
                codeImage.draw(in: rect)
                let avatarSize = CGSize(width: rect.size.width*0.25, height: rect.size.height*0.25)

                let x = (rect.width - avatarSize.width) * 0.5
                let y = (rect.height - avatarSize.height) * 0.5
                iconImage.draw(in: CGRect(x: x, y: y, width: avatarSize.width, height: avatarSize.height))

                let resultImage = UIGraphicsGetImageFromCurrentImageContext()

                UIGraphicsEndImageContext()
                return resultImage
            }
            return codeImage
        }
        return nil
}