【iOS开发】生成高斯模糊效果背景

//创建高斯模糊效果的背景
func createBlurBackground (image:UIImage,view:UIView,blurRadius:Float) {
    //处理原始NSData数据
    let originImage = CIImage(CGImage: image.CGImage )
    //创建高斯模糊滤镜
    let filter = CIFilter(name: "CIGaussianBlur")
    filter.setValue(originImage, forKey: kCIInputImageKey)
    filter.setValue(NSNumber(float: blurRadius), forKey: "inputRadius")
    //生成模糊图片
    let context = CIContext(options: nil)
    let result:CIImage = filter.valueForKey(kCIOutputImageKey) as! CIImage
    let blurImage = UIImage(CGImage: context.createCGImage(result, fromRect: result.extent()))
    //将模糊图片加入背景
    let w = self.view.frame.width
    let h = self.view.frame.height
    let blurImageView = UIImageView(frame: CGRectMake(-w/2, -h/2, 2*w, 2*h)) //模糊背景是界面的4倍大小
    blurImageView.contentMode = UIViewContentMode.ScaleAspectFill //使图片充满ImageView
    blurImageView.autoresizingMask = UIViewAutoresizing.FlexibleWidth | UIViewAutoresizing.FlexibleHeight //保持原图长宽比
    blurImageView.image = blurImage
    self.view.insertSubview(blurImageView, belowSubview: view) //保证模糊背景在原图片View的下层
}

self.createBlurBackground(img, view: self.gifView, blurRadius: 50)