iOS开发中给图片添加高斯模糊效果

方法如下：

CIContext *context = [CIContext contextWithOptions:nil];

CIImage *inputImage = [[CIImage alloc] initWithImage:[UIImage imageNamed:@"1.png"]];

// create gaussian blur filter

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

[filter setValue:inputImage forKey:kCIInputImageKey];

[filter setValue:[NSNumber numberWithFloat:10.0] forKey:@"inputRadius"]; // 数值越大，模糊度越高

// blur image

CIImage *result = [filter valueForKey:kCIOutputImageKey];

CGImageRef cgImage = [context createCGImage:result fromRect:[result extent]];

UIImage *image = [UIImage imageWithCGImage:cgImage];

CGImageRelease(cgImage);

self.mainImageView.image = image;