ios 屏幕截图

// 高斯模糊
CIContext *context = [CIContext contextWithOptions:nil];
CIImage *inputImage = [[CIImage alloc] initWithImage:image];
CIFilter *filter = [CIFilter filterWithName:@"CIGaussianBlur"];
[filter setValue:inputImage forKey:kCIInputImageKey];
[filter setValue:@2.0f forKey: @"inputRadius"];
CIImage *result = [filter valueForKey:kCIOutputImageKey];
CGImageRef outImage = [context createCGImage: result fromRect:[result extent]];
UIImage *blurImage = [UIImage imageWithCGImage:outImage];
CGImageRelease(outImage);