iOS 图片背景模糊效果

CoreImage实现:iOS 图片背景模糊效果

- (void)viewDidLoad {  

[super viewDidLoad];    

UIImage * image = [UIImage imageNamed:@"icon"];/*..CoreImage中的模糊效果滤镜..*/  

//CIImage,相当于UIImage,作用为获取图片资源  

CIImage * ciImage = [[CIImage alloc]initWithImage:image];  

//CIFilter,高斯模糊滤镜  

CIFilter * blurFilter = [CIFilter filterWithName:@"CIGaussianBlur"];  

//将图片输入到滤镜中  

[blurFilter setValue:ciImage forKey:kCIInputImageKey];  

//用来查询滤镜可以设置的参数以及一些相关的信息  

NSLog(@"%@",[blurFilter attributes]);  

//设置模糊程度,默认为10,取值范围(0-100)  

[blurFilter setValue:@(20) forKey:@"inputRadius"];  

//将处理好的图片输出  

CIImage * outCiImage = [blurFilter valueForKey:kCIOutputImageKey];  

//CIContext CIContext * context = [CIContext contextWithOptions:nil];  

//获取CGImage句柄,也就是从数据流中取出图片  

CGImageRef outCGImage = [context createCGImage:outCiImage fromRect:[outCiImage extent]];  

//最终获取到图片  

UIImage * blurImage = [UIImage imageWithCGImage:outCGImage];  

//释放CGImage句柄  

CGImageRelease(outCGImage);  

UIImageView * imageView = [[UIImageView alloc]initWithFrame:self.view.bounds];  

imageView.image = blurImage;  

[self.view addSubview:imageView];

}