使用Photokit使用元数据编写照片

我目前正在使用ALAsset框架将图像从Photo库保存到带有元数据的文档目录。 我使用的代码是

ALAssetsLibrary *library = [[[ALAssetsLibrary alloc] init] autorelease]; [library assetForURL:[NSURL URLWithString:miv.assetURL] resultBlock:^(ALAsset *asset) { ALAssetRepresentation *image_representation = [asset defaultRepresentation]; CGImageSourceRef source = Nil; uint8_t *buffer = (Byte*)malloc(image_representation.size); NSUInteger length = [image_representation getBytes:buffer fromOffset: 0.0 length:image_representation.size error:nil]; if (length != 0) { NSData *adata = [[NSData alloc] initWithBytesNoCopy:buffer length:image_representation.size freeWhenDone:YES]; NSDictionary* sourceOptionsDict = [NSDictionary dictionaryWithObjectsAndKeys:(id)[image_representation UTI] ,kCGImageSourceTypeIdentifierHint,nil]; // create CGImageSource with NSData source = CGImageSourceCreateWithData((__bridge CFDataRef) adata, (__bridge CFDictionaryRef) sourceOptionsDict); } NSDictionary *metadata = [image_representation metadata]; NSMutableDictionary *metadataAsMutable = [metadata mutableCopy]; NSMutableDictionary *EXIFDictionary = [metadataAsMutable objectForKey:(NSString *)kCGImagePropertyExifDictionary]; NSMutableDictionary *GPSDictionary = [metadataAsMutable objectForKey:(NSString *)kCGImagePropertyGPSDictionary]; if(!EXIFDictionary) { EXIFDictionary = [NSMutableDictionary dictionary]; } if(!GPSDictionary) { GPSDictionary = [NSMutableDictionary dictionary]; } [metadataAsMutable setObject:EXIFDictionary forKey:(NSString *)kCGImagePropertyExifDictionary]; [metadataAsMutable setObject:GPSDictionary forKey:(NSString *)kCGImagePropertyGPSDictionary]; CFStringRef UTI = CGImageSourceGetType(source); NSMutableData *dest_data = [NSMutableData data]; CGImageDestinationRef destination CGImageDestinationCreateWithData((__bridge CFMutableDataRef)dest_data,UTI,1,NULL); CGImageDestinationAddImageFromSource(destination,source,0, (__bridge CFDictionaryRef) metadataAsMutable); BOOL success = NO; success = CGImageDestinationFinalize(destination); if(!success) { } [dest_data writeToFile:myImageFileName atomically:YES]; CFRelease(destination); CFRelease(source); }]; 

我想将此代码转换为使用Photo Kit。 根据我的研究，我发现Photo Kit将处理写入的方式

 PHFetchResult *savedAssets = [PHAsset fetchAssetsWithLocalIdentifiers:[NSArray arrayWithObjects:imageURLString, nil] options:nil]; [savedAssets enumerateObjectsUsingBlock:^(PHAsset *asset, NSUInteger idx, BOOL *stop) { [[PHImageManager defaultManager] requestImageForAsset:(PHAsset *)asset targetSize:desiredSize contentMode:PHImageContentModeAspectFit options:Nil resultHandler:^(UIImage *result, NSDictionary *info) { // Write Here // The info here has no EXIF or Metadata. So get them PHContentEditingInputRequestOptions *editOptions = [[PHContentEditingInputRequestOptions alloc]init]; editOptions.networkAccessAllowed = YES; [asset requestContentEditingInputWithOptions:editOptions completionHandler:^(PHContentEditingInput *contentEditingInput, NSDictionary *info) { CIImage *image = [CIImage imageWithContentsOfURL:contentEditingInput.fullSizeImageURL]; NSLog(@"metadata: %@", image.properties.description); ?? How do I write this to doc folder ? }]; } } 

Answer 1

经过一番研究，我弄明白了。 以下是使用Exif将图像保存到文档目录的方法。

 PHFetchResult *savedAssets = [PHAsset fetchAssetsWithLocalIdentifiers:[NSArray arrayWithObjects:myAssetURL, nil] options:nil]; [savedAssets enumerateObjectsUsingBlock:^(PHAsset *asset, NSUInteger idx, BOOL *stop) { PHImageRequestOptions *cropToSquare = [[PHImageRequestOptions alloc] init]; cropToSquare.synchronous = YES; [[PHImageManager defaultManager] requestImageDataForAsset:asset options:cropToSquare resultHandler: ^(NSData *imageData, NSString *dataUTI, UIImageOrientation orientation, NSDictionary *info) { CIImage* ciImage = [CIImage imageWithData:imageData]; NSMutableDictionary *metadataAsMutable = [ciImage.properties mutableCopy]; CGImageSourceRef source = Nil; NSDictionary* sourceOptionsDict = [NSDictionary dictionaryWithObjectsAndKeys:dataUTI ,kCGImageSourceTypeIdentifierHint,nil]; source = CGImageSourceCreateWithData((__bridge CFDataRef) imageData, (__bridge CFDictionaryRef) sourceOptionsDict); CFStringRef UTI = CGImageSourceGetType(source); NSMutableData *dest_data = [NSMutableData data]; CGImageDestinationRef destination = CGImageDestinationCreateWithData((__bridge CFMutableDataRef)dest_data,UTI,1,NULL); CGImageDestinationAddImageFromSource(destination,source,0, (__bridge CFDictionaryRef) metadataAsMutable); BOOL success = NO; success = CGImageDestinationFinalize(destination); if(!success) { } [dest_data writeToFile:myTrumbImageFileName atomically:YES]; CFRelease(destination); CFRelease(source); }]; }];