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;
}


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