[Digikam-devel] Rotation issue in image view

[Marcel Wiesweg]

I have now fixed the bug in SVN: If a full version is taken from the cache, it 
is rotated.
But, to be faster (scaling!), if there is a preview version as well, it is 
preferred.

> 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.

So what can we do about this?
See bug 131603: For some RAW files, the tag is correct.

Are there raw file formats for which the preview orientation is always right 
or wrong? Or do different camera models, using the same format, do this 
differently?

Looking at the sample images from the repository, there are at least four 
groups:

a) Correct in thumbnail, correct in preview, correct in full version
	6057_009.cr2
	DSC0028.arw
	DSC_2162.nef
	L1000877.DNG
	MINOLTA-DYNAX5D-01.MRW
	k10d.dng
b) Correct in thumbnail, correct in preview, _wrong_ in full version
	MINOLTA-DYNAX5D-03.MRW
	MINOLTA-DYNAX5D-04.MRW
c) Wrong (180°) in thumbnail, wrong (180°) in preview, correct in full version
	Canon-G5.crw
d) Wrong in thumbnail, wrong in preview, wrong in full version
	DSCF0019.raf
	S9500-vert.raf
	S9600-vert.raf

For case d) there is apparently no information about orientation. Or is this a 
feature of .RAF files?
For case c), there is, but why is it 180° wrong? Seems to be .crw specific.
Case b), I dont know.
Case a) is fortunately the largest group.

Marcel