Re: [gthumb-list] Bug: EXIF orientation is broken after resize

[Paolo Bacchilega <paolo bacchilega libero it>]

Il 02/02/2013 20:51, damien clochard ha scritto:
> Le 02/02/2013 04:36, Rennie deGraaf a écrit :
> > On 01/02/13 12:54 PM, damien clochard wrote:
> > > Le 29/01/2013 16:30, Dr. Michael J. Chudobiak a écrit :
> > > > > > the orientation field makes sense only in the original image, when you
> > > > > > create a new image it is better to reset it.
> > > > >
> > > > > Sorry again but I don't understand this logic. I don't see how resetting
> > > > > the orientation after a resize operation is useful to anyone. These are
> > > > > two different things. My understanding is that gthumb should keep this
> > > > > orientation when user ask for a resize.
> > > > >
> > > > > Am I correct ?
> > > >
> > > > No. The orientation tag is taken into account when the image is loaded
> > > > into memory.
> > > >
> > > > The resize happens on the image in memory.
> > >
> > > Yes I am aware that the transformation are executed "in memory" and not
> > > directly on disk :-) Anyway I don't see how this is related with the
> > > issue I described.
> >
> > As I understand it (forgive me if this has changed since I last looked
> > at the code), gThumb rotates every image that it loads to the "top-left"
> > orientation.  If it subsequently saves the image, it uses the rotated
> > image data and sets the EXIF tag to "top-left" to ensure that the tag
> > matches the data.
>
> Ok thanks for your explanations. I understand now that my problem has
> nothing to do with the resize operation. I still think that The Gimp has
> a better approach for this rotate-or-keep-exif-tag issue but that's not
> the subject here. Anyway let's close this discussion, and go back to my
> initial problem.
>
> The scenario is even simpler now :
>
> 1/ Open this file : http://nawak.taadeem.net/DSC_1114.orig.JPG
> 2/ Save it as DSC_1114.png
>
> The original photo is in portrait format.
>
> The NIKON file has the following tags :
>
>    X Dimension : 2896
>    Y Dimension : 1944
>    Orientation : left, bottom
>
> When Gthumb displays the picture as a thumbnail it's in portrait format.
> When the picture is in full screen mode is displayed in landscape.
>
> The PNG file has the following tags :
>
>    X Dimension : 2896
>    Y Dimension : 1944
>    Orientation : top, left
>
> see http://nawak.taadeem.net/DSC_1114.png
>
> I used gThumb 3.1.3

I cannot reproduce the problem, the image is always in portrait mode to me.

- Paolo