UIImagePickerController-iOS/iPhone拍摄的图像的访问元数据(exif标记)

显然,您可以在图像被拍摄后立即访问其元数据。选择图像后系统调用的协议方法是:

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info

NSDictionary参数info包含一个键: UIImagePickerControllerMediaMetadata

现在,如果我能找出如何获得exif标签或任何曝光水平信息,从中推断出基本信息的光水平,我会很高兴。:)

使用照片框架更新到iOS 11

目标C:

#import <Photos/Photos.h>

- (void)imagePickerController:(UIImagePickerController *)imagePicker didFinishPickingMediaWithInfo:(NSDictionary<NSString *,id> *)info {

    PHAsset* asset = info[UIImagePickerControllerPHAsset];

    [asset requestContentEditingInputWithOptions:nil completionHandler:^(PHContentEditingInput *contentEditingInput, NSDictionary *info) {
        CIImage *fullImage = [CIImage imageWithContentsOfURL:contentEditingInput.fullSizeImageURL];

        NSLog(@"%@", fullImage.properties.description);
    }];

    [imagePicker dismissViewControllerAnimated:YES completion:nil];
}

您还需要照片库使用权限(NSPhotoLibraryUsageDescription),然后可以添加以下代码以查看是否加载或查看是否显示

[PHPhotoLibrary requestAuthorization:^(PHAuthorizationStatus status) {
    switch (status) {
        case PHAuthorizationStatusAuthorized:
            NSLog(@"PHAuthorizationStatusAuthorized");
            break;
        case PHAuthorizationStatusDenied:
            NSLog(@"PHAuthorizationStatusDenied");
            break;
        case PHAuthorizationStatusNotDetermined:
            NSLog(@"PHAuthorizationStatusNotDetermined");
            break;
        case PHAuthorizationStatusRestricted:
            NSLog(@"PHAuthorizationStatusRestricted");
            break;
    }
}];