ios - CIUnsharpMask 不工作？

Question

我正在尝试使用 CIUnsharpMask 过滤器来处理图像。问题是返回的图像是空白的。图像视图中没有出现任何内容。我一直在为我的其余过滤器使用相同的模板，并且它们运行良好。radiusValue 和 intensityValue 都是 NSNumbers 顺便说一句。

CIImage *ciUnsharpMaskImage = [[CIImage alloc] initWithImage:preFilterImage];
CIContext *ciUnsharpMaskContext = [CIContext contextWithOptions:nil];
CIFilter *ciUnsharpMaskFilter = [CIFilter filterWithName:@"CIUnsharpMask" 
                                          keysAndValues: kCIInputImageKey, ciUnsharpMaskImage, 
                               @"inputRadius", radiusValue,
                                 @"inputIntensity", intensityValue, nil];
CIImage *ciUnsharpMaskOutputImage = [ciUnsharpMaskFilter outputImage];
CGImageRef ciUnsharpMaskCgimg = [ciUnsharpMaskContext 
                                 createCGImage:ciUnsharpMaskOutputImage 
                                 fromRect:[ciUnsharpMaskOutputImage extent]];
preFilterImage = [UIImage imageWithCGImage:ciUnsharpMaskCgimg];
CGImageRelease(ciUnsharpMaskCgimg);
NSLog(@"unsharp mask filter applied");

[self.imageView setImage:preFilterImage]; 

Answer 1

CIUnsharpMask 在 iOS 6 中被添加到 Core Image。

Answer 2

没关系，我使用以下代码来获取可用过滤器的列表，而 CIUnsharpMask 不是其中之一:(

NSArray *supportedFilters = [CIFilter filterNamesInCategory:kCICategoryBuiltIn];
for (CIFilter *filter in supportedFilters) {
    NSString *string = [NSString stringWithFormat:@"%@",[[CIFilter filterWithName:(NSString *)filter] inputKeys]];
    NSLog(@"%@ %@", filter, string);
}