[Digikam-devel] Rotation issue in image view

[Gilles Caulier]

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.

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
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