[Digikam-users] About the exif orientation tag and how digikam handles it

Pedro Venda pjvenda at pjvenda.org
Sun Sep 10 23:30:35 BST 2006


Hi again,

On Sunday 10 September 2006 22:59, Caulier Gilles wrote:
> > I've recently bought a digital SLR camera
>
> Witch camera exactly ?

Canon EOS 350D (Digital Rebel XT in the US)

> In current implementation from svn (next 0.9.0-beta2 release), there are 3
> new features about auto-rotation based on Exif :
>
> --> ther is a new tool to rebuild the thumbnails database in background.
> --> changing 'Show images/thumbs rotated according to orientation tag'
> option will ask to user if this new tool need to be started.
> --> F5 key will re-build the thumbnails from the current album only.

The thumbnail rebuild feature is be very welcome!

Will this affect the images themselves when we click the thumbnail? I 
understand that the thumbnails may have a different treatment because not all 
cameras generate them equally, but that shouldn't be for the images... I 
guess.

The way it works now, if the thumbnail shows up in the wrong orientation, 
clicking on it, shows the image also in the wrong position. It seems that the 
program is ignoring the tag all along...

> > Even though it wasn't really a solution but more a workaround, I solved
> > this once by checking the "rotate/flip image" box in the camera import
> > dialog [4], but now I can't even reproduce it - all imported pictures
> > show up as landscape shots even with different exif orientation tag.

It would be hard to verify it right now, but I think that this referred import 
was made in digikam 0.8.2 and now I'm using 0.9.0, hence the different 
behaviour.

> > Another way to solve this was the 'jhead -autorot *.JPG', but that's just
> > like eliminating the exif orientation tag...
>
> (:=))). Too bad...

hmm, I guess it may not be such a bad idea. I've seen the bug report you 
pointed me to...

> > The way I think it should work is by rendering the pictures and
> > thumbnails oriented according to the exif orientation tag, independently
> > from scanning or importing the files - like picasa does. (sorry for the
> > comparison) What do you think about this? Is this a bug or am I
> > interpreting the exif orientation tag wrongly?
>
> Yes, certainly.

err, I didn't understand your reply: certainly what?

> > [1]: http://mega.ist.utl.pt/~pjlv/sshot-01-version.jpg
> > [2]: http://mega.ist.utl.pt/~pjlv/sshot-02-configure.jpg
> > [3]: http://mega.ist.utl.pt/~pjlv/sshot-03-nonrotated.jpg
> > [4]: http://mega.ist.utl.pt/~pjlv/sshot-04-rotated.jpg
>
> Thanks for the sample images. I will investiguate next week.

no sweat. :)

Cheers,
Pedro Venda.
-- 

Pedro João Lopes Venda
email: pjvenda at pjvenda org
http://www.pjvenda.org
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