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

[Caulier Gilles]

Le Dimanche 10 Septembre 2006 23:42, Pedro Venda a écrit :
> Hi everyone,
>
> I've looked around the archives and googled a fair bit about this
> subject/issue but couldn't find any solid answer. So I decided to ask the
> guys who know, at the cost of potentially being publicly humiliated with a
> bold RTFM :) - hope not.
>
> I've recently bought a digital SLR camera 

Witch camera exactly ?

> and already I've got about 3GB of 
> photo albums. I use digikam and picasa to handle my photo albums, but
> digikam is a better, more robust and more complete product.
>
> All of my photos have the following exif orientation tags:
> * top, left - for landscape shots
> * left, bottom - for portrait shots (right hand up)
>
> In digikam 0.9.0-beta1 [1], by checking the Settings -> Configure Digikam
> -> Metadata -> "Show images/thumbs rotated according to orientation tag"
> [2] box, I hoped to get a thumbnail preview screen similar to picasa's,
> with "left, bottom" pictures vertically oriented (that's what the exif
> orientation tag is there for). However, it doesn't happen; All pictures
> show up as landscape shots [3]. I believe this is a bug, but I may be
> missing something.

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.

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

(:=))). Too bad...

>
> 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.

>
> [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.

>
> Congratulations for a great software and keep up the excelent work!

Thanks to support digiKam project !

Gilles Caulier