IOS 如何获取与修改图片的EXIF信息

简介：Exif是一种图像文件格式，它的数据存储与JPEG格式是完全相同的。实际上Exif格式就是在JPEG格式头部插入了数码照片的信息，包括拍摄时的光圈、快门、白平衡、ISO、焦距、日期时间等各种和拍摄条件以及相机品牌、型号、色彩编码、拍摄时录制的声音以及GPS全球定位系统数据、缩略图等。你可以利用任何可以查看JPEG文件的看图软件浏览Exif格式的照片，但并不是所有的图形程序都能处理Exif信息。

获取EXIF信息代码如下：

- (NSMutableDictionary *)getExifInfoWithImageData:(NSData *)imageData{
CGImageSourceRef cImageSource = CGImageSourceCreateWithData((__bridge CFDataRef)imageData, NULL);
NSDictionary *dict =  (NSDictionary *)CFBridgingRelease(CGImageSourceCopyPropertiesAtIndex(cImageSource, 0, NULL));
NSMutableDictionary *dictInfo = [NSMutableDictionary dictionaryWithDictionary:dict];
return dictInfo;
}

修复EXIF信息代码如下：

/*
* 仅支持JPEG格式
*/
-(NSMutableData *)setExifInfoWithImageData:(NSData *)imageNSData{
CGImageSourceRef imgSource = CGImageSourceCreateWithData((__bridge_retained CFDataRef)imageNSData, NULL);

NSDictionary *metadata = (__bridge NSDictionary *)CGImageSourceCopyPropertiesAtIndex(imgSource, 0, NULL);

NSMutableDictionary *metadataAsMutable = [metadata mutableCopy];

NSMutableDictionary *EXIFDictionary = [[metadataAsMutable objectForKey:(NSString *)kCGImagePropertyExifDictionary] mutableCopy];
if (EXIFDictionary==nil) {
EXIFDictionary = [[NSMutableDictionary alloc] init];
}
[EXIFDictionary setObject:@"mengxiaoxiong"
forKey:(NSString *)kCGImagePropertyExifUserComment];

[metadataAsMutable setObject:EXIFDictionary forKey:(NSString *)kCGImagePropertyExifDictionary];

NSLog(@"Info: %@",metadataAsMutable);

CFStringRef UTI = CGImageSourceGetType(imgSource);

NSMutableData *newImageData = [NSMutableData data];

CGImageDestinationRef destination = CGImageDestinationCreateWithData((__bridge CFMutableDataRef)newImageData, UTI, 1, NULL);

if(!destination)
NSLog(@"***创建 失败***");

CGImageDestinationAddImageFromSource(destination, imgSource, 0, (__bridge CFDictionaryRef) metadataAsMutable);

BOOL success = NO;
success = CGImageDestinationFinalize(destination);

if(!success)
NSLog(@"***保存 失败***");
return newImageData;
}