当我将图像资源添加到iOS 8.4 Photos集合中的相册时，我正在尝试添加/修改图像元数据。以下代码成功添加了GPS字典，但未添加或更改EXIF数据（我已检查过图像标题并使用EXIF工具进行确认）。我尝试了两种不同的方法（参见altSetMyImageInfo），但结果相同。我错过了什么？
@property (nonatomic) CLLocation *location;
. . .
[self.stillImageOutput captureStillImageAsynchronouslyFromConnection:connection completionHandler:^( CMSampleBufferRef imageDataSampleBuffer, NSError *error ) {
if ( imageDataSampleBuffer ) {
NSData *imageData = [AVCaptureStillImageOutput jpegStillImageNSDataRepresentation:imageDataSampleBuffer];
CFDictionaryRef tempDict = CMCopyDictionaryOfAttachments(NULL, imageDataSampleBuffer, kCMAttachmentMode_ShouldPropagate);
CFMutableDictionaryRef theDict = CFDictionaryCreateMutableCopy(NULL, 0, tempDict);
[self setMyImageInfo:theDict];
[self setMyLocation:theDict];
CGImageSourceRef source = CGImageSourceCreateWithData((__bridge CFDataRef)imageData, NULL);
CFStringRef UTI = CGImageSourceGetType(source);
NSMutableData *newImageData = [NSMutableData data];
CGImageDestinationRef destination = CGImageDestinationCreateWithData((__bridge CFMutableDataRef)newImageData,UTI,1,NULL);
BOOL success = CGImageDestinationFinalize(destination);
CFRelease(destination);
CFRelease(source);
}
}
. . .
if ( [PHAssetResourceCreationOptions class] ) {
[[PHAssetCreationRequest creationRequestForAsset] addResourceWithType:PHAssetResourceTypeFullSizePhoto data:newImageData options:nil];
}
else {
NSError *error = nil;
[newImageData writeToURL:temporaryFileURL options:NSDataWritingAtomic error:&error];
if ( error ) {
NSLog( @"Error: %@", error );
}
else {
PHAssetChangeRequest *newImageRequest = [PHAssetChangeRequest creationRequestForAssetFromImageAtFileURL:temporaryFileURL];
PHAssetCollectionChangeRequest *albumChangeRequest = [PHAssetCollectionChangeRequest changeRequestForAssetCollection:theAlbum];
[albumChangeRequest addAssets:@[newImageRequest.placeholderForCreatedAsset]];
}
. . .
- (void) setMyImageInfo:(CFMutableDictionaryRef)theDict
{
NSMutableDictionary *exif = [NSMutableDictionary dictionary];
[exif setObject:@"2.2.2" forKey:(NSString *)kCGImagePropertyExifVersion];
[exif setObject:@“MyIdentity” forKey:(NSString *)kCGImagePropertyExifImageUniqueID];
[exif setObject:@"I hope this works!" forKey:(NSString *)kCGImagePropertyExifUserComment];
CFDictionarySetValue(theDict, kCGImagePropertyExifDictionary, (__bridge void *)exif);
}
- (void) setMyLocation:(CFMutableDictionaryRef)theDict
{
NSMutableDictionary *gps = [NSMutableDictionary dictionary];
[gps setObject:@"2.2.0.0" forKey:(NSString *)kCGImagePropertyGPSVersion];
NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
[formatter setDateFormat:@"HH:mm:ss.SSSSSS"];
[formatter setTimeZone:[NSTimeZone timeZoneWithAbbreviation:@"UTC"]];
[gps setObject:[formatter stringFromDate:self.location.timestamp] forKey:(NSString *)kCGImagePropertyGPSTimeStamp];
[formatter setDateFormat:@"yyyy:MM:dd"];
[gps setObject:[formatter stringFromDate:self.location.timestamp] forKey:(NSString *)kCGImagePropertyGPSDateStamp];
CGFloat latitude = self.location.coordinate.latitude;
if (latitude < 0) {
latitude = -latitude;
[gps setObject:@"S" forKey:(NSString *)kCGImagePropertyGPSLatitudeRef];
} else {
[gps setObject:@"N" forKey:(NSString *)kCGImagePropertyGPSLatitudeRef];
}
[gps setObject:[NSNumber numberWithFloat:latitude] forKey:(NSString *)kCGImagePropertyGPSLatitude];
CGFloat longitude = self.location.coordinate.longitude;
if (longitude < 0) {
longitude = -longitude;
[gps setObject:@"W" forKey:(NSString *)kCGImagePropertyGPSLongitudeRef];
} else {
[gps setObject:@"E" forKey:(NSString *)kCGImagePropertyGPSLongitudeRef];
}
[gps setObject:[NSNumber numberWithFloat:longitude] forKey:(NSString *)kCGImagePropertyGPSLongitude];
CGFloat altitude = self.location.altitude;
if (!isnan(altitude)){
if (altitude < 0) {
altitude = -altitude;
[gps setObject:@"1" forKey:(NSString *)kCGImagePropertyGPSAltitudeRef];
} else {
[gps setObject:@"0" forKey:(NSString *)kCGImagePropertyGPSAltitudeRef];
}
[gps setObject:[NSNumber numberWithFloat:altitude] forKey:(NSString *)kCGImagePropertyGPSAltitude];
}
if (self.location.speed >= 0){
[gps setObject:@"K" forKey:(NSString *)kCGImagePropertyGPSSpeedRef];
[gps setObject:[NSNumber numberWithFloat:self.location.speed*3.6] forKey:(NSString *)kCGImagePropertyGPSSpeed];
}
if (self.location.course >= 0){
[gps setObject:@"T" forKey:(NSString *)kCGImagePropertyGPSTrackRef];
[gps setObject:[NSNumber numberWithFloat:self.location.course] forKey:(NSString *)kCGImagePropertyGPSTrack];
}
CFDictionarySetValue(theDict, kCGImagePropertyGPSDictionary, (__bridge void *)gps);
}
- (void) altSetMyImageInfo:(CFMutableDictionaryRef)theDict
{
CFStringRef imageUniqueID = CFStringCreateWithCString(NULL, [@“MyImageID” cStringUsingEncoding:NSASCIIStringEncoding], kCFStringEncodingASCII);
CFDictionarySetValue(theDict, kCGImagePropertyExifImageUniqueID, imageUniqueID);
CFRelease (imageUniqueID);
CFStringRef userComment = CFStringCreateWithCString(NULL, [@"I hope this works!" cStringUsingEncoding:NSASCIIStringEncoding], kCFStringEncodingASCII);
CFDictionarySetValue(theDict, kCGImagePropertyExifUserComment, userComment);
CFRelease (userComment);
}
答案 0 :(得分：1)
这个问题的答案涉及很多事情。一个小例子，“CGImageSourceRef source”丢失了。最重要的是，由于“你们都知道谁”的NDA限制，我无法将问题纳入项目的环境中（你们最好知道因为我不能说）。我没有解析问题，而是在代码中发布了答案。如果您将此代码插入“您知道谁”的某个示例程序中（我不能说示例名称，但maCVA可能会为您提供搜索其开发人员库的线索）。我已经做到这一点，以便大多数代码将位于某个大型源文件的末尾，其他行具有参考行号（开始插入顶部）。唯一的另一个变化是头文件将CLLocationManagerDelegate添加到@interface。您可能还想将位置服务添加到plist中。
我已经包含调试代码以查看日志文件中的元数据。剩下的唯一问题是使用CFDictionarySetValue还是“setObject：forKey：”来分配字典值。我使用前者作为EXIF / TIFF数据，后者使用GPS数据，但在EXIF / TIFF方法中包含“setObject：forKey：”代码作为注释。两者都有效。 “setObject：forKey：”更简洁。有什么意见吗？
@import CoreLocation; // MAS: for GPS (line 11)
@property (strong, nonatomic) CLLocationManager *locationManager; // MAS: for image metadata (line 42)
@property (nonatomic) CLLocation *location; // MAS: get it early and save it here (line 43)
@property (assign, nonatomic) id< CLLocationManagerDelegate > delegate; // MAS: do we really need this? (line 44)
/* MAS: Instantiate location manager (in viewDidLoad, about line 70)
*/
self.locationManager = [[CLLocationManager alloc] init];
/* MAS: end
*/
[self startStandardUpdates]; // MAS: get our location (in viewDidLoad about line 201, not quite at the end)
/* MAS: (still in veiwDidLoad about line 206 after dispatch)
*/
if ([CLLocationManager locationServicesEnabled]) {
NSLog(@"location services enabled");
}
else {
NSLog( @"Could not add location services to the session" );
// self.setupResult = PikBitSetupResultSessionConfigurationFailed;
// Display alert to the user.
UIAlertController *alert = [UIAlertController alertControllerWithTitle:@"Location services"
message:@"Location services are not enabled on this device. Please enable location services in settings."
preferredStyle:UIAlertControllerStyleAlert];
UIAlertAction* defaultAction = [UIAlertAction actionWithTitle:@"Dismiss" style:UIAlertActionStyleDefault
handler:^(UIAlertAction * action) {}]; // NULL action to dismiss the alert.
[alert addAction:defaultAction];
[self presentViewController:alert animated:YES completion:nil];
}
if ([CLLocationManager authorizationStatus] == kCLAuthorizationStatusNotDetermined)
{
[self.locationManager requestWhenInUseAuthorization];
NSLog(@"location authorization status not determined");
} else if ([CLLocationManager authorizationStatus] == kCLAuthorizationStatusDenied) {
NSLog(@"location services authorization was previously denied by the user.");
// Display alert to the user.
UIAlertController *alert = [UIAlertController alertControllerWithTitle:@"Location services"
message:@"Location services were previously denied by the user. Please enable location services for this app in settings."
preferredStyle:UIAlertControllerStyleAlert];
UIAlertAction* defaultAction = [UIAlertAction actionWithTitle:@"Dismiss" style:UIAlertActionStyleDefault
handler:^(UIAlertAction * action) {}]; // Do nothing action to dismiss the alert.
[alert addAction:defaultAction];
[self presentViewController:alert animated:YES completion:nil];
}
/* MAS: end
*/
/* MAS: about line 616, once you have image NSData
*/
CFDictionaryRef tempDict = CMCopyDictionaryOfAttachments(NULL, imageDataSampleBuffer, kCMAttachmentMode_ShouldPropagate);
CFMutableDictionaryRef theDict = CFDictionaryCreateMutableCopy(NULL, 0, tempDict);
[self setMyImageInfo:theDict];
[self setMyLocation:theDict];
CGImageSourceRef source = CGImageSourceCreateWithData((__bridge CFDataRef)imageData, NULL);
CFStringRef UTI = CGImageSourceGetType(source);
NSMutableData *newImageData = [NSMutableData data];
CGImageDestinationRef destination = CGImageDestinationCreateWithData((__bridge CFMutableDataRef)newImageData,UTI,1,NULL);
if(!destination) {
NSLog(@"***Could not create image destination ***");
}
CGImageDestinationAddImageFromSource(destination,source,0, (CFDictionaryRef) theDict);
BOOL success = CGImageDestinationFinalize(destination);
CFRelease(destination);
CFRelease(source);
if( success ) {
NSLog(@"it worked, let's see the metadata");
[self checkEXIF:newImageData];
}
else {
NSLog(@"***Could not create data from image destination ***");
}
/* MAS: end
*/
[[PHAssetCreationRequest creationRequestForAsset] addResourceWithType:PHAssetResourceTypePhoto data:newImageData options:nil]; // MAS: change data to 'NewImageData' (about line 654)
[newImageData writeToURL:temporaryFileURL options:NSDataWritingAtomic error:&error]; // MAS: change source to newImageData (about line 668)
/* MAS: start (immediately before @end)
*/
#pragma mark - location delegate methods
// Start the standard location service
- (void)startStandardUpdates
{
// set the delegate and the parameters
self.locationManager.delegate = self;
self.locationManager.desiredAccuracy = kCLLocationAccuracyHundredMeters;
// Set a movement threshold for new events.
self.locationManager.distanceFilter = 500; // meters
[self.locationManager startUpdatingLocation];
NSLog(@"location manager started");
}
// Delegate methods
- (void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray *)locations {
// If it's a relatively recent event, turn off updates to save power.
self.location = [locations lastObject];
NSLog(@"location manager delegate used");
NSDate* eventDate = self.location.timestamp;
NSTimeInterval howRecent = [eventDate timeIntervalSinceNow];
if (fabs(howRecent) < 15.0) {
// If the event is recent, do something with it.
NSLog(@"latitude %+.6f, longitude %+.6f\n",
self.location.coordinate.latitude,
self.location.coordinate.longitude);
}
else {
NSLog(@"latitude %+.6f, longitude %+.6f\n",
self.location.coordinate.latitude,
self.location.coordinate.longitude);
}
/* MAS: for optimizing usage (later)
[manager stopUpdatingLocation]; // If we only want one update.
manager.delegate = nil; // We might be called again here, even though we
// called "stopUpdatingLocation", so remove us as the delegate to be sure.
*/
}
- (void)locationManager:(CLLocationManager *)manager didFailWithError:(NSError *)error {
// report any errors returned back from Location Services
NSLog(@"location manager error - %@", error.description);
}
- (void) setMyImageInfo:(CFMutableDictionaryRef)theDict
{
NSString *temp = @"This is a very long string, used to test the loading of the image description field";
NSString *tempID = @"ABCDEFGHIJKLMNOPQRSTUVWXYZ012345"; // used to test imageUniqueID field, should the 33rd character be a nul?
//
if (theDict) {
// save a dictionary of the TIFF image properties
CFDictionaryRef tiffData = CFDictionaryGetValue(theDict, kCGImagePropertyTIFFDictionary);
CFMutableDictionaryRef tiffDataMut;
if (tiffData) {
tiffDataMut = CFDictionaryCreateMutableCopy(nil, 0, tiffData);
}
else {
tiffDataMut = CFDictionaryCreateMutable(nil, 0,
&kCFTypeDictionaryKeyCallBacks, &kCFTypeDictionaryValueCallBacks);
}
// The best place to store a long string --
CFStringRef imageDescription = CFStringCreateWithCString(NULL, [temp cStringUsingEncoding:NSASCIIStringEncoding], kCFStringEncodingASCII);
CFDictionarySetValue(tiffDataMut, kCGImagePropertyTIFFImageDescription, imageDescription);
CFRelease (imageDescription);
// Carry the brand into the image --
CFStringRef software = CFStringCreateWithCString(NULL, [@"MyApp" cStringUsingEncoding:NSASCIIStringEncoding], kCFStringEncodingASCII);
CFDictionarySetValue(tiffDataMut, kCGImagePropertyTIFFSoftware, software);
CFRelease (software);
// Carry the manufacturer into the image --
CFStringRef make = CFStringCreateWithCString(NULL, [@"Apple" cStringUsingEncoding:NSASCIIStringEncoding], kCFStringEncodingASCII);
CFDictionarySetValue(tiffDataMut, kCGImagePropertyTIFFMake, make);
CFRelease (make);
// Carry the device name into the image --
CFStringRef model = CFStringCreateWithCString(NULL, [@"iPhone" cStringUsingEncoding:NSASCIIStringEncoding], kCFStringEncodingASCII);
CFDictionarySetValue(tiffDataMut, kCGImagePropertyTIFFModel, model);
CFRelease (model);
CFDictionarySetValue(theDict, kCGImagePropertyTIFFDictionary, tiffDataMut);
CFRelease(tiffDataMut);
// Now do the same for EXIF
// save a dictionary of the EXIF image properties
CFDictionaryRef exifData = CFDictionaryGetValue(theDict, kCGImagePropertyExifDictionary);
CFMutableDictionaryRef exifDataMut;
if (exifData) {
exifDataMut = CFDictionaryCreateMutableCopy(nil, 0, exifData);
}
else {
exifDataMut = CFDictionaryCreateMutable(nil, 0,
&kCFTypeDictionaryKeyCallBacks, &kCFTypeDictionaryValueCallBacks);
}
// This is a good place to store an ID, but it only holds 33 characters --
CFStringRef imageUniqueID = CFStringCreateWithCString(NULL, [tempID cStringUsingEncoding:NSASCIIStringEncoding], kCFStringEncodingASCII);
CFDictionarySetValue(exifDataMut, kCGImagePropertyExifImageUniqueID, imageUniqueID);
CFRelease (imageUniqueID);
// Just to see that it works --
CFStringRef userComment = CFStringCreateWithCString(NULL, [@"I hope this works! And it does!!" cStringUsingEncoding:NSASCIIStringEncoding], kCFStringEncodingASCII);
CFDictionarySetValue(exifDataMut, kCGImagePropertyExifUserComment, userComment);
CFRelease (userComment);
CFDictionarySetValue(theDict, kCGImagePropertyExifDictionary, exifDataMut);
CFRelease(exifDataMut);
}
else {
NSLog(@"Metadata Dictionairy for image empty");
}
/* alternative version (this has been tested and works) --
// Create dictionaries -
NSMutableDictionary *exif = [NSMutableDictionary dictionary];
NSMutableDictionary *tiff = [NSMutableDictionary dictionary];
// load some TIFF and EXIF data --
[tiff setObject:temp forKey:(NSString *)kCGImagePropertyTIFFImageDescription];
[tiff setObject:@"Apple" forKey:(NSString *)kCGImagePropertyTIFFMake];
[tiff setObject:@"iPhone" forKey:(NSString *)kCGImagePropertyTIFFModel];
[tiff setObject:@"PikLips" forKey:(NSString *)kCGImagePropertyTIFFSoftware];
[exif setObject:@"I hope this works! And it does, too!!" forKey:(NSString *)kCGImagePropertyExifUserComment];
[exif setObject:tempID forKey:(NSString *)kCGImagePropertyExifImageUniqueID];
// load the info into the passed CFMutableDictionaryRef --
CFDictionarySetValue(theDict, kCGImagePropertyExifDictionary, (__bridge void *)exif);
CFDictionarySetValue(theDict, kCGImagePropertyTIFFDictionary, (__bridge void *)tiff);
* end
*/
}
- (void) setMyLocation:(CFMutableDictionaryRef)theDict
{
NSMutableDictionary *gps = [NSMutableDictionary dictionary];
[gps setObject:@"2.2.0.0" forKey:(NSString *)kCGImagePropertyGPSVersion];
NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
[formatter setDateFormat:@"HH:mm:ss.SSSSSS"];
[formatter setTimeZone:[NSTimeZone timeZoneWithAbbreviation:@"UTC"]];
[gps setObject:[formatter stringFromDate:self.location.timestamp] forKey:(NSString *)kCGImagePropertyGPSTimeStamp];
[formatter setDateFormat:@"yyyy:MM:dd"];
[gps setObject:[formatter stringFromDate:self.location.timestamp] forKey:(NSString *)kCGImagePropertyGPSDateStamp];
CGFloat latitude = self.location.coordinate.latitude;
if (latitude < 0) {
latitude = -latitude;
[gps setObject:@"S" forKey:(NSString *)kCGImagePropertyGPSLatitudeRef];
} else {
[gps setObject:@"N" forKey:(NSString *)kCGImagePropertyGPSLatitudeRef];
}
[gps setObject:[NSNumber numberWithFloat:latitude] forKey:(NSString *)kCGImagePropertyGPSLatitude];
CGFloat longitude = self.location.coordinate.longitude;
if (longitude < 0) {
longitude = -longitude;
[gps setObject:@"W" forKey:(NSString *)kCGImagePropertyGPSLongitudeRef];
} else {
[gps setObject:@"E" forKey:(NSString *)kCGImagePropertyGPSLongitudeRef];
}
[gps setObject:[NSNumber numberWithFloat:longitude] forKey:(NSString *)kCGImagePropertyGPSLongitude];
CGFloat altitude = self.location.altitude;
if (!isnan(altitude)){
if (altitude < 0) {
altitude = -altitude;
[gps setObject:@"1" forKey:(NSString *)kCGImagePropertyGPSAltitudeRef];
} else {
[gps setObject:@"0" forKey:(NSString *)kCGImagePropertyGPSAltitudeRef];
}
[gps setObject:[NSNumber numberWithFloat:altitude] forKey:(NSString *)kCGImagePropertyGPSAltitude];
}
if (self.location.speed >= 0){
[gps setObject:@"K" forKey:(NSString *)kCGImagePropertyGPSSpeedRef];
[gps setObject:[NSNumber numberWithFloat:self.location.speed*3.6] forKey:(NSString *)kCGImagePropertyGPSSpeed];
}
if (self.location.course >= 0){
[gps setObject:@"T" forKey:(NSString *)kCGImagePropertyGPSTrackRef];
[gps setObject:[NSNumber numberWithFloat:self.location.course] forKey:(NSString *)kCGImagePropertyGPSTrack];
}
CFDictionarySetValue(theDict, kCGImagePropertyGPSDictionary, (__bridge void *)gps);
}
#pragma mark debug
// This is used to verify the metadata loading
- (void)checkEXIF:(NSData *) imageData {
CGImageSourceRef myImageSource = CGImageSourceCreateWithData((__bridge CFDataRef)imageData, NULL);
CFDictionaryRef imagePropertiesDictionary;
CFDictionaryRef tiffPropertiesDictionary;
CFDictionaryRef exifPropertiesDictionary;
NSDictionary *options = [NSDictionary dictionaryWithObjectsAndKeys:
[NSNumber numberWithBool:NO], (NSString *)kCGImageSourceShouldCache,
nil];
imagePropertiesDictionary = CGImageSourceCopyPropertiesAtIndex(myImageSource,0, (CFDictionaryRef)options);
/* these value are produced by the system
*/
CFNumberRef imageWidth = (CFNumberRef)CFDictionaryGetValue(imagePropertiesDictionary, kCGImagePropertyPixelWidth);
CFNumberRef imageHeight = (CFNumberRef)CFDictionaryGetValue(imagePropertiesDictionary, kCGImagePropertyPixelHeight);
int w = 0;
int h = 0;
CFNumberGetValue(imageWidth, kCFNumberIntType, &w);
CFNumberGetValue(imageHeight, kCFNumberIntType, &h);
// NSDictionary *propertiesDict = (NSDictionary *)CFBridgingRelease(imagePropertiesDictionary); // this assignment throws an exception later in the code
NSLog(@"Image Width: %d",w);
NSLog(@"Image Height: %d",h);
// NSLog(@"Image Properties: %@", propertiesDict);
/* These values are what we added --
*/
tiffPropertiesDictionary = CFDictionaryGetValue(imagePropertiesDictionary,kCGImagePropertyTIFFDictionary);
if ( tiffPropertiesDictionary ) {
NSString *make = (NSString *)CFDictionaryGetValue(tiffPropertiesDictionary, kCGImagePropertyTIFFMake);
NSString *model = (NSString *)CFDictionaryGetValue(tiffPropertiesDictionary, kCGImagePropertyTIFFModel);
NSString *imageDescription = (NSString *)CFDictionaryGetValue(tiffPropertiesDictionary, kCGImagePropertyTIFFImageDescription);
NSString *software = (NSString *)CFDictionaryGetValue(tiffPropertiesDictionary, kCGImagePropertyTIFFSoftware);
NSLog(@"Image Description: %@", imageDescription);
NSLog(@"Make: %@", make);
NSLog(@"Model: %@", model);
NSLog(@"Software: %@", software);
}
else {
NSLog(@"No TIFF dictionary");
}
exifPropertiesDictionary = CFDictionaryGetValue(imagePropertiesDictionary,kCGImagePropertyExifDictionary);
if ( exifPropertiesDictionary ) {
NSString *uniqueID = (__bridge NSString *)CFDictionaryGetValue(exifPropertiesDictionary, kCGImagePropertyExifImageUniqueID);
NSString *userComment = (__bridge NSString *)CFDictionaryGetValue(exifPropertiesDictionary, kCGImagePropertyExifUserComment);
NSLog(@"Unique ID: %@", uniqueID);
NSLog(@"User comment: %@", userComment);
}
else {
NSLog(@"No EXIF dictionary");
}
CFRelease(imagePropertiesDictionary);
}
/* MAS: end
*/