[Digikam-devel] Rotation issue in image view

[Achim Bohnet]

On Monday, 5. March 2007, Gilles Caulier wrote:
> Marcel,
> 
> There is a _very_ important things to understand about RAW files :
> 
> Preview  != full image !
> 
> ...of course about the image data, the image size, etc, but also about
> the rotation flag.
> 
> RAW file is a contatiner witch include the CCD RAW camera data and a
> preview image (generally a JPEG image) witch is used by camera to
> render on a screen tv (for example)
> 
> The preview orientation can be completly different of RAW image data !
> This is depending of how the camera orientation flag have be set by
> user after the shot (for example to render the picture to the small
> screen of camera)
> 
> This way how is handle RAW pictures and preview suck roally, but we
> must drive it as well.
> 
> This why it's wrong to use the Exif orientation tags with RAW preview.
> This tags is right with the full RAW image, not the preview image.

Does it make sense to add a save guard here?  Like x/y of full image
!= x/y of thumbnail  ==> present a dialog with once left and once right
rotated.  User clicks one one of them and the corrected preview get's
saved?

Achim
> 
> Gilles
> 
> 
> 2007/3/5, Marcel Wiesweg <marcel.wiesweg at gmx.de>:
> >
> > Ok, the problem is simple:
> > Previews are rotated in the loading thread, before they are put in the
> > cache.
> > Full version are rotated by DImgInterface, after they are put in the cache.
> > (There is a comment that dcraw automatically rotates the images, but that
> > does
> > not hold for previews?)
> > So if the preview uses the full version, it is not rotated.
> >
> > Marcel
> > _______________________________________________
> > Digikam-devel mailing list
> > Digikam-devel at kde.org
> > https://mail.kde.org/mailman/listinfo/digikam-devel
> >
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> 
> 



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