[Digikam-devel] virtual rotation of image...

Gilles Caulier caulier.gilles at gmail.com
Tue Dec 23 14:16:11 GMT 2008

Marcel, The problem is more complex than this.

We cannot use only one BD flag to set orientation of image. Why ? because
image representation in digiKam is taken from different place.

I will take an ex with RAW file which are more complex case. For ex, with my
Dynax 5D camera, MRW as an embeded preview (a 640*480 JPEG file). This
preview is used to display thumbs in icon view and preview of raw in embeded
view mode.

If i take a vertically oriented image with my camera, the preview on camera
screen is generally badly oriented and image is displayed vertically with
screen oriented horizonally. It's not optimum especially with small screen
from camera.

So generaly i decide to rotate preview with my camera to judge if image is
valid or not. This modifity preview image orientation in Minolta Makernote.
This have side effect in digiKam : all are badly oriented...

To solve this problem, KPhotoAlbum use a databse flag for thumb. The user
can adjust it without to touch the file. I think we must do the same.

About preview, i'm not yet sure, but i think than we nedd to do the same
(another one flag in Database). A least for the moment we can set a flag and
see if we will need it really.

And filanlly, sometime the same behaviours need to be done with Raw decoded
image. I have see some RAW file (especially Kodak) where exif orientation
flag is never adapted when image is taken vertically.

To resume : it's a big puzzle. I think than user need to have the choise to
adjust orientation of image on screen in all situation using flags in



2008/12/23 Marcel Wiesweg <marcel.wiesweg at gmx.de>

> > Marcel, Andi,
> >
> > I would to solve several entries in bugzilla about rotation of :
> >
> > 1/ thumbnails,
> > 2/ Preview
> > 3/ real image data for read only files.
> >
> > For all these cases, a respective flag in database is require (excepted
> if
> > you have a better solution.
> >
> > With case 1/ a new button can be displayed over thumbnail as Gwenview.
> > Same with case 2 in preview mode.
> > With case 3/ a new menu entry can be created.
> >
> > The JPEGLossLess kipi-plugin must be adapted accordingly (some code are
> > empty in digiKam kipi interface). same with exif rotation flag
> adjustement
> > option.
> >
> > What do you think about ? Is DB schema/interface is ready for that ?
> We have the field orientation in ImageInformation. Value is the enum from
> libkexiv2. The orientation exif flag is read to the db when scanning images
> but it is used nowhere to actually rotate the image.
> Shouldnt this db flag be kept in sync with the image metadata in all
> situations? At least, when we can write to the file.
> >
> > Best
> >
> > Gilles Caulier
> _______________________________________________
> Digikam-devel mailing list
> Digikam-devel at kde.org
> https://mail.kde.org/mailman/listinfo/digikam-devel
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