我正在尝试过滤从 imagePicker 获得的图像。原始图像在我的代码中存储得非常好，但是当我尝试使用 CIFilter 对其进行过滤时，生成的 UIImage“filteredImage”大小为 0x0 像素。
我在这里发布了完整的功能，它是图像选择器委托方法。
更新：过滤器“CISepiaTone”有效，并为我提供了尺寸正确的图像。但是 CIColorMonochrome 在 iOS 上也可用，我通过询问 CIFilter 来检查可用的过滤器选项。
更新 2：找到它 - inputColor 参数必须是 CIColor 类型而不是 UIColor，我在参考中忽略了这一点。
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {
UIImage *image = [info objectForKey:UIImagePickerControllerOriginalImage];
// Filter the image
CIImage *filterImage = [[CIImage alloc] initWithCGImage:image.CGImage];
CIFilter *colorMono = [CIFilter filterWithName:@"CIColorMonochrome"];
[colorMono setDefaults];
[colorMono setValue:filterImage forKey:@"inputImage"];
[colorMono setValue:[UIColor yellowColor] forKey:@"inputColor"];
CIImage *outputImage = [colorMono outputImage];
CIContext *con = [CIContext contextWithOptions:nil];
CGImageRef filteredImageRef = [con createCGImage:outputImage fromRect:[outputImage extent]];
UIImage *filteredImage = [UIImage imageWithCGImage:filteredImageRef scale:1.0f orientation:UIImageOrientationUp];
// filteredImage dimensions are 0x0 px here!
CGImageRelease(filteredImageRef);
// Save image in imageStore
CFUUIDRef uniqueId = CFUUIDCreate(kCFAllocatorDefault);
CFStringRef uniqueIdStringRef = CFUUIDCreateString(kCFAllocatorDefault, uniqueId);
NSString *key = (__bridge NSString *)uniqueIdStringRef;
[[FPImageStore sharedStore] setImage:filteredImage forKey:key];
imageKey = key;
CFRelease(uniqueId);
CFRelease(uniqueIdStringRef);
// Dismiss imagePicker viewController
[self dismissViewControllerAnimated:YES completion:nil];
}