ios - 在 UIImage 上模糊

Question

如何更改 UIImage 中模糊的颜色？我需要黑色模糊，但我不知道该怎么做。我在 Stackoverflow ( Blur UIImage to achieve effect like passcode blur of the wallpaper with swift ) 中找到了另一个答案。这个答案很完美，但是模糊很浅，我需要它是黑色的。谁能帮我？PS:下面的代码是另一个问题的答案。

func applyBlurEffect(image: UIImage){
   var imageToBlur = CIImage(image: image)
   var blurfilter = CIFilter(name: "CIGaussianBlur")
   blurfilter.setValue(5, forKey: kCIInputRadiusKey)
   blurfilter.setValue(imageToBlur, forKey: "inputImage")
   var resultImage = blurfilter.valueForKey("outputImage") as! CIImage
   var blurredImage = UIImage(CIImage: resultImage)
   var cropped:CIImage=resultImage.imageByCroppingToRect(CGRectMake(0, 0,imageToBlur.extent().size.width, imageToBlur.extent().size.height))
   blurredImage = UIImage(CIImage: cropped)
   self.backgroundImage.image = blurredImage
}

Answer 1

let imageView = UIImageView(image: UIImage(named: "example"))
imageView.frame = view.bounds
imageView.contentMode = .ScaleToFill
view.addSubview(imageView)

let blurEffect = UIBlurEffect(style: .Dark)
let blurredEffectView = UIVisualEffectView(effect: blurEffect)
blurredEffectView.frame = imageView.bounds
view.addSubview(blurredEffectView)