IOS中使得图片模糊的效果的方法

-(void)blurUserView

{

    

//     DOWN_IMAGE(userView, STRING_VALUE(userDict[@"avatar_big"]), SMALL_IMAGE);

   CIContext *context = [CIContextcontextWithOptions:nil];

   CIImage *inputImage = [[CIImagealloc]initWithContentsOfURL:[NSURLURLWithString:STRING_VALUE(userDict[@"avatar_big"])]];

   CIFilter *filter = [CIFilterfilterWithName:@"CIGaussianBlur"];

    [filtersetValue:inputImage forKey:kCIInputImageKey];

    [filter setValue:[NSNumbernumberWithFloat:2]forKey:@"inputRadius"];

   CIImage *result = [filter valueForKey:kCIOutputImageKey];

    

   CGImageRef cgImage = [context createCGImage:result fromRect:CGRectMake(0, -25,180, 250)];

   UIImage *image = [UIImageimageWithCGImage:cgImage];

   CGImageRelease(cgImage);

   userView.image = image;

    

}