How to export Apple's new RAW photo format .dng in iOS 10?

Question

I'm having trouble exporting Apple's new RAW photo format .dng.

UIActivityViewController exports the photo as JPEG, which defeats the purpose.

Any help is much appreciated.

Answer 1

Here's how I fixed the issue.

-(void)activityAction{
PHAsset *asset = self.assetsFetchResults[(int)self.image_number];

PHImageRequestOptions *options = [[PHImageRequestOptions alloc] init];
options.synchronous = NO;
options.version = PHImageRequestOptionsVersionCurrent;
options.deliveryMode = PHImageRequestOptionsDeliveryModeOpportunistic;
options.resizeMode = PHImageRequestOptionsResizeModeNone;
options.networkAccessAllowed = NO;//HAS TO BE YES TO DOWNLOAD FROM THE CLOUD AND PROGRESS TO SHOW
/*options.progressHandler =  ^(double progress,NSError *error,BOOL* stop, NSDictionary* dict) {
    NSLog(@"progress %lf",progress);  //never gets called
};*/

[[PHImageManager defaultManager] requestImageDataForAsset:asset options:options resultHandler:^(NSData *imageData, NSString *dataUTI, UIImageOrientation imageOrientation, NSDictionary *info){

    NSURL *assetURL = [info objectForKey:@"PHImageFileURLKey"];
    NSString *photoFormat = [assetURL pathExtension];

    NSURL *temporaryDNGFileURL;

    NSArray *activityItems;

    if([photoFormat isEqualToString:@"DNG"] && [[UIDevice currentDevice].systemVersion floatValue] >= 10){
        NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
        NSString *documentsDirectory = [paths objectAtIndex:0];
        NSDateFormatter *format = [[NSDateFormatter alloc] init];
        [format setDateFormat:@"MMddyyyyHHmmss"];
        NSString *assetDateString = [format stringFromDate:[NSDate date]];
        NSString *assetPath = [documentsDirectory stringByAppendingPathComponent:[assetDateString stringByAppendingString:@".dng"]];
        temporaryDNGFileURL = [NSURL fileURLWithPath:assetPath];
        [imageData writeToURL:temporaryDNGFileURL atomically:YES];

        activityItems = @[temporaryDNGFileURL];
    }
    else{
        UIImage *shareImage = [[UIImage alloc] initWithData:imageData];

        activityItems = @[shareImage];
    }

    UIActivityViewController *activityVC = [[UIActivityViewController alloc] initWithActivityItems:activityItems applicationActivities:nil];
    activityVC.excludedActivityTypes = @[UIActivityTypeSaveToCameraRoll];
    activityVC.modalTransitionStyle = UIModalTransitionStyleCoverVertical;
    [self presentViewController:activityVC animated:YES completion:nil];

    [activityVC setCompletionWithItemsHandler:^(NSString *activityType, BOOL completed, NSArray *returnedItems, NSError *activityError) {
        NSString *ServiceMsg = nil;
        if( [activityType isEqualToString:UIActivityTypeMail] )           ServiceMsg = @"Mail Done";
        if( [activityType isEqualToString:UIActivityTypeMessage] ) ServiceMsg = @"Message Done";
        if( [activityType isEqualToString:UIActivityTypeAirDrop] ) ServiceMsg = @"AirDrop Done";
        if( [activityType isEqualToString:UIActivityTypePostToTwitter] )  ServiceMsg = @"Twitter Done";
        if( [activityType isEqualToString:UIActivityTypePostToFacebook] ) ServiceMsg = @"Facebook Done";
        if( [activityType isEqualToString:UIActivityTypePostToFlickr] ) ServiceMsg = @"Flickr Done";
        if( [activityType isEqualToString:UIActivityTypePostToTencentWeibo] ) ServiceMsg = @"Weibo Done";

        if(completed){
            [customActivityActionPressedTimer invalidate];
            customActivityActionPressedTimer = nil;
            customActivityAction = 0;
            [[NSUserDefaults standardUserDefaults] setInteger:0 forKey:@"customActivityAction"];

            NSLog(@"ACTIVITY VIEW DONE");

            if([[NSFileManager defaultManager] fileExistsAtPath:temporaryDNGFileURL.path]){
                NSError *error;
                [[NSFileManager defaultManager] removeItemAtPath:temporaryDNGFileURL.path error:&error];
                if(error){
                    NSLog(@"RAW DNG FILE DELETE FAILED");
                }
                else{
                    NSLog(@"RAW DNG FILE DELETED");
                }
            }
        }
        else{
            [customActivityActionPressedTimer invalidate];
            customActivityActionPressedTimer = nil;
            customActivityAction = 0;
            [[NSUserDefaults standardUserDefaults] setInteger:0 forKey:@"customActivityAction"];

            NSLog(@"ACTIVITY VIEW CANCEL");

            if([[NSFileManager defaultManager] fileExistsAtPath:temporaryDNGFileURL.path]){
                NSError *error;
                [[NSFileManager defaultManager] removeItemAtPath:temporaryDNGFileURL.path error:&error];
                if(error){
                    NSLog(@"RAW DNG FILE DELETE FAILED");
                }
                else{
                    NSLog(@"RAW DNG FILE DELETED");
                }
            }
        }
    }];
}];

}