Sort by EXIF Orientation not working

[famffc]

I'm running XnView 1.98 (English) on Windows XP - when i'm in the browser mode, I tried to right click -> Sort by -> Orientation.

I can see the images order did changed - but not in the expected order (orientation).

Double checked the EXIF data, the pictures do have have different EXIF orientation value (eg top left, left bottom etc).
Just that for some reason, it didn't sort/group it into the order that make sense..

For example, after i select Sort by Orientation, the order would be (image #1, image #2, ...):
top-left, top-bottom, top-bottom, top-bottom, top-left, top-bottom, top-bottom....
expected them to be at least
top-left, top-left, top-bottom, top-bottom, top-bottom, top-bottom, top-bottom....

[xnview]

It's not EXIF orientation but orientation of picture

[famffc]

Thanks for the response and clearing up doubts on this.

This triggers a question from me (apologies if this is not the right place to ask).

I actually wanted to perform batch lossless rotation based on EXIF orientation.

I know this can achieved using the Batch Processing mode. However, what happened is that if the image does not required any rotation (according to the EXIF orientation), XnView will stil process that image and produce the image according to the write JPG output (eg whether you choose to keep EXIF data, what's your compression rate etc). So the output new JPG image will still be slightly different from the original file you had. This is what surprised me and not the behavior I expected.

Is that a way to either:
1) Batch lossless rotate JPG files, based on the EXIF orientation - and only rotate if the EXIF says it's needed, and ignore the ones that don't need. When I say ignores, I mean leave the file totally untouched and do not process it at all
2) Sort by EXIF orientation so I can select/tag the images I want to rotate easily ?

[marsh]

Hello famffc,
The problem with Exif rotation is that program does not create Exif data where it has not previously existed.
There is option... Browser>Misc>[ ]Change Exif orientation ONLY when possible (JPEG)
However, I suggest this be removed or not used because of the limitation. It is easy to imagine wanting to rotate based on orientation or not. And puzzling to see a combination of both in my opinion. Sort by orientation in browser can already group these rotated jpegs as a workaround. To see them you may have to enable thumbnails and Options... General>Operations>[x]Rotate images according to Exif flag
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Edit: Sort by orientation worked the first time, but not after restart for me.

[famffc]

Thanks for you input marsh.

I guess i'll go back to my initial plan... hand picked the images that needs to rotate and send them to rotate by EXIF - out of 10k photos...
The select all + batch processing/rotate by EXIF is good for majority, but it's doing extra things that I preferred not to.

[marsh]

It's not EXIF orientation but orientation of picture

Now I see it. Landscape vs. portrait. I need to reselect this sort method each time for effect to be seen.