Swift根据文字生成二维码

  //MARK:- 生成二维码
  static func creatQRCodeImage(text: String, WH: CGFloat) -> UIImage{
    
    //创建滤镜
    let filter = CIFilter(name: "CIQRCodeGenerator")
    //还原滤镜的默认属性
    filter?.setDefaults()
    //设置需要生成二维码的数据
    filter?.setValue(text.data(using: String.Encoding.utf8), forKey: "inputMessage")
    //从滤镜中取出生成的图片
    let ciImage = filter?.outputImage
    //这个清晰度好
    let bgImage = createNonInterpolatedUIImageFormCIImage(image: ciImage!, size: WH)
    
    return bgImage
}


static func createNonInterpolatedUIImageFormCIImage(image: CIImage, size: CGFloat) -> UIImage {
    
    let extent: CGRect = image.extent.integral
    let scale: CGFloat = min(size/extent.width, size/extent.height)
    
    let width = extent.width * scale
    let height = extent.height * scale
    let cs: CGColorSpace = CGColorSpaceCreateDeviceGray()
    let bitmapRef = CGContext(data: nil, width: Int(width), height: Int(height), bitsPerComponent: 8, bytesPerRow: 0, space: cs, bitmapInfo: 0)!
    
    let context = CIContext(options: nil)
    let bitmapImage: CGImage = context.createCGImage(image, from: extent)!
    
    bitmapRef.interpolationQuality = CGInterpolationQuality.none
    bitmapRef.scaleBy(x: scale, y: scale)
    bitmapRef.draw(bitmapImage, in: extent)
    let scaledImage: CGImage = bitmapRef.makeImage()!
    return UIImage(cgImage: scaledImage)
}