iOS：在Marker APP3上访问JPEG元数据
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我一直在以以下方式使用Exif标记在jpeg文件上存储一些数据：
CGImageSourceRef source = CGImageSourceCreateWithURL(baseURL, NULL);
NSDictionary *metadata = (NSDictionary *) CGImageSourceCopyPropertiesAtIndex(source,0,NULL);
NSMutableDictionary *metadataAsMutable = [[metadata mutableCopy]autorelease];
NSMutableDictionary *EXIFDictionary = [[[metadataAsMutable objectForKey:(NSString *)kCGImagePropertyExifDictionary]mutableCopy]autorelease];
[EXIFDictionary setObject:[NSString stringWithFormat:@\"%d\",tag] forKey:(NSString *)kCGImagePropertyExifUserComment];
没有找到相关结果
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粟痢凰副
NSString *filePath = currentImageObject.myFilePath; NSFileHandle *fileHandle = [NSFileHandle fileHandleForUpdatingAtPath:filePath]; if(!fileHandle){ return; } [fileHandle seekToEndOfFile]; unsigned long long eofOffset = [fileHandle offsetInFile];BOOL markerFound = NO; BOOL dqtFound = NO; while ((!markerFound) && (!dqtFound) && ([fileHandle offsetInFile] < eofOffset)) { currentOffset += 1; [fileHandle seekToFileOffset:currentOffset]; NSData *markerData = [fileHandle readDataOfLength:1]; currentOffset += 1; NSInteger markerValue = (unsigned char)*(unsigned char *)[markerData bytes]; if (0xe0 == markerValue) { currentOffset += 14; [fileHandle seekToFileOffset:currentOffset]; NSData *xThumbnailData = [fileHandle readDataOfLength:1]; currentOffset += 1; NSData *yThumbnailData = [fileHandle readDataOfLength:1]; currentOffset += 1; NSInteger xThumbnail = (unsigned char)*(unsigned char *)[xThumbnailData bytes]; NSInteger yThumbnail = (unsigned char)*(unsigned char *)[yThumbnailData bytes]; NSInteger thumbnailSize = 3 * xThumbnail * yThumbnail; currentOffset += thumbnailSize; [fileHandle seekToFileOffset:currentOffset]; } else if (0xe3 == markerValue) { markerFound = YES; break; } else if (0xdb == markerValue) { dqtFound = YES; break; } else { NSData *lengthData = [fileHandle readDataOfLength:2]; currentOffset += 2; NSInteger length = (unsigned short)*(unsigned short *)[lengthData bytes]; length = NSSwapBigShortToHost(length); length -= 2; currentOffset += length; [fileHandle seekToFileOffset:currentOffset]; } }