[Digikam-users] Lossless rotation is lossy!

Bast! bast at abwesend.de
Tue Apr 15 22:41:53 BST 2014

Same for me. But that is the point, Digikam (at least my installation)
does change the pixel data.

Would you be so kind and try the test I proposed?

I did some more testing and the weird thing is:

When I rotate an image 90 or 270 degrees, I have a difference between
the original (O) and the rotated (R) image. The difference between the
original and the 90 degree rotation is equal to the difference of the
original and the 270 degrees rotation.

When digikam rotates 90 further, the difference is gone.

    O = R180
O-R90 = O-R270

So changing the orientation from landscape to portrait or vice versa
introduces a pixel error that is removed on another orientation change.

I guess, I will have to live with that, because it seems to be either
unnoticed or tolerated for quite a while now.

Can anybody clarify this?

Thx in advance!

Am 15.04.2014 22:24, schrieb Marcel Wiesweg:
> For me lossless qualifies as lossless if you rotate forth and rotate back and 
> the resulting file, at least the pixel data, is identical to the original 
> unrotated form
> _______________________________________________
> Digikam-users mailing list
> Digikam-users at kde.org
> https://mail.kde.org/mailman/listinfo/digikam-users

More information about the Digikam-users mailing list