iOS Swift生成二维码

最开始要使用二维码的时候，我还有点犯难。但是查看资料后发现我想多了，苹果为我们提供了CoreImage类库，用他就能直接生成二维码啦。直接上代码：

import UIKit

class ViewController: UIViewController {

    @IBOutlet weak var qrCodeImageView: UIImageView!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        //访问的url
        let url = "https://www.jianshu.com/u/01b7a2dd26e8";
        //你的头像（可以为nil）
        let headerImage = UIImage(named: "header")
        //生成图片并且显示
        qrCodeImageView.image = setupQRCodeImage(url, image: headerImage)
    }

}

//MARK: -传进去字符串,生成二维码图片
func setupQRCodeImage(_ text: String, image: UIImage?) -> UIImage {
    //创建滤镜
    let filter = CIFilter(name: "CIQRCodeGenerator")
    filter?.setDefaults()
    //将url加入二维码
    filter?.setValue(text.data(using: String.Encoding.utf8), forKey: "inputMessage")
    //取出生成的二维码（不清晰）
    if let outputImage = filter?.outputImage {
        //生成清晰度更好的二维码
        let qrCodeImage = setupHighDefinitionUIImage(outputImage, size: 300)
        //如果有一个头像的话，将头像加入二维码中心
        if var image = image {
            //给头像加一个白色圆边（如果没有这个需求直接忽略）
            image = circleImageWithImage(image, borderWidth: 50, borderColor: UIColor.white)
            //合成图片
            let newImage = syntheticImage(qrCodeImage, iconImage: image, width: 100, height: 100)
            
            return newImage
        }
        
        return qrCodeImage
    }
    
    return UIImage()
}

//image: 二维码 iconImage:头像图片 width: 头像的宽 height: 头像的宽
func syntheticImage(_ image: UIImage, iconImage:UIImage, width: CGFloat, height: CGFloat) -> UIImage{
    //开启图片上下文
    UIGraphicsBeginImageContext(image.size)
    //绘制背景图片
    image.draw(in: CGRect(origin: CGPoint.zero, size: image.size))
    
    let x = (image.size.width - width) * 0.5
    let y = (image.size.height - height) * 0.5
    iconImage.draw(in: CGRect(x: x, y: y, width: width, height: height))
    //取出绘制好的图片
    let newImage = UIGraphicsGetImageFromCurrentImageContext()
    //关闭上下文
    UIGraphicsEndImageContext()
    //返回合成好的图片
    if let newImage = newImage {
        return newImage
    }
    return UIImage()
}

//MARK: - 生成高清的UIImage
func setupHighDefinitionUIImage(_ image: CIImage, size: CGFloat) -> UIImage {
    let integral: CGRect = image.extent.integral
    let proportion: CGFloat = min(size/integral.width, size/integral.height)
    
    let width = integral.width * proportion
    let height = integral.height * proportion
    let colorSpace: CGColorSpace = CGColorSpaceCreateDeviceGray()
    let bitmapRef = CGContext(data: nil, width: Int(width), height: Int(height), bitsPerComponent: 8, bytesPerRow: 0, space: colorSpace, bitmapInfo: 0)!
    
    let context = CIContext(options: nil)
    let bitmapImage: CGImage = context.createCGImage(image, from: integral)!
    
    bitmapRef.interpolationQuality = CGInterpolationQuality.none
    bitmapRef.scaleBy(x: proportion, y: proportion);
    bitmapRef.draw(bitmapImage, in: integral);
    let image: CGImage = bitmapRef.makeImage()!
    return UIImage(cgImage: image)
}

//生成边框
func circleImageWithImage(_ sourceImage: UIImage, borderWidth: CGFloat, borderColor: UIColor) -> UIImage {
    let imageWidth = sourceImage.size.width + 2 * borderWidth
    let imageHeight = sourceImage.size.height + 2 * borderWidth
    
    UIGraphicsBeginImageContextWithOptions(CGSize(width: imageWidth, height: imageHeight), false, 0.0)
    UIGraphicsGetCurrentContext()
    
    let radius = (sourceImage.size.width < sourceImage.size.height ? sourceImage.size.width:sourceImage.size.height) * 0.5
    let bezierPath = UIBezierPath(arcCenter: CGPoint(x: imageWidth * 0.5, y: imageHeight * 0.5), radius: radius, startAngle: 0, endAngle: .pi * 2, clockwise: true)
    bezierPath.lineWidth = borderWidth
    borderColor.setStroke()
    bezierPath.stroke()
    bezierPath.addClip()
    sourceImage.draw(in: CGRect(x: borderWidth, y: borderWidth, width: sourceImage.size.width, height: sourceImage.size.height))
    
    let image = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()
    
    return image!
}

Simulator Screen Shot - iPhone 8 Plus - 2018-04-05 at 11.44.26.png

好啦，就是这么简单。