[digiKam-users] Exported image orientation different that in-Digikam display -- inconsistent XMP/EXIF/TIFF data?

[Daniel Bauer]

Am 09.07.22 um 14:42 schrieb PGNet Dev:
> I have a jpg image displayed in Digikam/Linux (installed as AppImage, 
> https://download.kde.org/stable/digikam/7.7.0/digiKam-7.7.0-x86-64.appimage.mirrorlist) 
> 
> 
>      v 7.7.0
>      Build date: 6/22/22 5:33 PM (target: RelWithDebInfo)
>      Revision: 8c835009cbf361de37452987191633583f9d985c
>      Branch: HEAD
> 
> It's been imported from an Apple iPhone.
> 
> Its orientation has been rotated in Digikam so that it's vertically 
> oriented, with height (4032) > width (3024).
> It's displayed -- in Digikam -- correctly.
> 
> Consistently, in Digikam's Metadata -> ExifTool tab
> 
>      EXIF
>          ExifImageHeight   4032
>          ExifImageWidth    3024
>          ImageHeight       4032
>          ImageWidth        3024
>          Orientation       Horizontal(normal)
> 
>      XMP
>          ExifImageHeight   4032
>          ExifImageWidth    3024
>          ImageHeight       4032
>          ImageWidth        3024
>          Orientation       Horizontal(normal)
> 
> and in the Metadata -> XMP tab,
> 
>      Exif-specific Properties
>          Pixel X Dimension   3024
>          Pixel Y Dimension   4032
> 
> But, on export of the Image to my Android phone, I note the image is 
> incorrecly rotated -- 90 degrees.
> 
> Checking the file's details in the viewer (F-Stop), I find
> 
>      Image Width    4032
>      IMage Height   3024
>      Orientation    Top, left side (Horizontal / normal)
> 
> which is clearly inconsistent with the Digikam EXIF/XMP data.
> 
> Checking back in Digikam's Metadata -> XMP tab, I also find,
> 
>      TIFF Properties
>          Image Length   4032
>          Image Width    3024
>          Orientation    top, left
> 
> , from which the incorrect @android 'Orientation' seems to originate ... ??
> 
> Finally, in Digikam's Settings -> Metadata -> Rotation, settings are
> 
>      When rotating a file
>          [ ] Rotate by only setting a flag
>          [X] Rotate by changing the content if possible
>              [ ] Even allow lossy rotation if necessary
>          [X] Write flag to metadat if possible
>      Rotate actions
>          [X] Show images/thumbnails rotate according to orientation tag
>          [X] Set orientation tag to normal after rotate/flip
> 
> What needs to be done in Digikam to
> 
>      (1) correct & ensure consistency of all Digikam database rotation data
>      (2) ensure consistency of the database rotation data with XMP 
> sidecards
>      (3) ensure that the exported data is written correctly
> 
> , so that the exported image gets consistent rotation data, and displays 
> correctly ?


I have never investigated an further, but I realized that when I rotate 
an image in the album view, it shows rotated all over digikam, but not 
outside (i.e. when I run an imageMagick script to resize, add a text 
etc.), then the image is not rotated, i.e. appears as before the rotation.

But when I open the image in digikam editor, rotate it there and save 
it, rotation persists also outside of digikam.

There is a notable difference in processing time whether I rotate in 
album thumbnails (immediate) or in editor (a tiny little bit of time).

So digikam obviously rotates in different manners whether in album view 
or in editor, but as said I have never investigated, I just click on it 
to open in editor and rotate there... but I don't rotate a lot :-)

This different behavior still exists in my digikam 7.1.0/opensuse rpm
-- 
Daniel Bauer photographer Basel Málaga
https://www.patreon.com/danielbauer
https://www.daniel-bauer.com