IOS图片的高斯模糊

- (void)viewDidLoad {
    [super viewDidLoad];
    //高斯模糊效果
    CIContext *context=[CIContext contextWithOptions:nil];
    CIImage *inputImage=[[CIImage alloc]initWithImage:[UIImage imageNamed:@"Tutorial_p4"]];
    CIFilter *filter=[CIFilter filterWithName:@"CIGaussianBlur"];
    [filter setValue:inputImage forKey:kCIInputImageKey];
    /**
     *  value的值是模糊的程度，值越大，模糊程度越大。
     */
    [filter setValue:[NSNumber numberWithFloat:20.0] forKey:@"inputRadius"];
    //blur image
    CIImage *result=[filter valueForKey:kCIOutputImageKey];
    CGImageRef  cgImage=[context createCGImage:result fromRect:[result extent]];
    UIImage *image=[UIImage imageWithCGImage:cgImage];
    CGImageRelease(cgImage);
    UIImageView *myImageV=[[UIImageView alloc]initWithFrame:CGRectMake(0, 0, 320, 480)];
    myImageV.image=image;
    [self.view addSubview:myImageV];
    // Do any additional setup after loading the view.
}