iOS 模糊效果

    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
        CIContext *context = [CIContext contextWithOptions:nil];
        CIImage *ciImage = [CIImage imageWithCGImage:image.CGImage];
        CIFilter *filter = [CIFilter filterWithName:@"CIGaussianBlur"];
        [filter setValue:ciImage forKey:kCIInputImageKey];
        /// 模糊程度
        [filter setValue:@15.0f forKey: @"inputRadius"];
        CIImage *result = [filter valueForKey:kCIOutputImageKey];
        CGImageRef outImage = [context createCGImage: result fromRect:ciImage.extent];
        UIImage *blurImage = [UIImage imageWithCGImage:outImage];
        dispatch_async(dispatch_get_main_queue(), ^{
            self.iconBGView.image = blurImage;
        });
    });