swift-生成二维码（可带图片）

import UIKit

class ViewController:
UIViewController {

    override
func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        // 不带图片的二维码图片
        let imageViewIcon1 =
UIImageView(frame: CGRect(x:
20, y: 20, width:
150, height: 150))
        imageViewIcon1.image =
createQRForString("MR.G", qrImageName:
"")
        self.view.addSubview(imageViewIcon1)
        
        // 带图片的二维码图片
        let imageViewIcon2 =
UIImageView(frame: CGRect(x:
200, y: 20, width:
150, height: 150))
        imageViewIcon2.image =
createQRForString("MR.G", qrImageName:
"2")
        self.view.addSubview(imageViewIcon2)
        
    }

    override
func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }
    
    func createQRForString(qrString:
String?, qrImageName: String?) ->
UIImage? {
        if
let sureQRString = qrString {
            let stringData = sureQRString.dataUsingEncoding(NSUTF8StringEncoding,
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")
            // 二维码颜色
            colorFilter?.setValue(CIColor(red:
1, green: 1, blue:
1), forKey: "inputColor0")
            // 二维码背景色
            colorFilter?.setValue(CIColor(red:
0, green: 0, blue:
0), forKey: "inputColor1")
            // 返回二维码image
            let codeImage =
UIImage(CIImage: colorFilter!.outputImage!.imageByApplyingTransform(CGAffineTransformMakeScale(5,
5)))
            // 通常，二维码都是定制的，中间的都会放想要表达意思的图片
            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.drawInRect(rect)
                let avatarSize =
CGSize(width: rect.size.width *
0.25, height: rect.size.height
                    * 0.25)
                let x = (rect.size.width - avatarSize.width)
* 0.5
                let y = (rect.size.height - avatarSize.height)
* 0.5
                iconImage.drawInRect(CGRect(x: x, y: y, width: avatarSize.width, height:
avatarSize.height))
                
                let resultImage =
UIGraphicsGetImageFromCurrentImageContext()
                
                UIGraphicsEndImageContext()
                return resultImage
            }
            return codeImage
        }
        return
nil
    }
}