Re: gwenview thumbnails

On Mon, 9 Oct 2006 13:01:28 +0200, Héder Balázs <[email protected]> wrote:
> Hi,
> 
> I'm using gwenview 1.4.0 and I found a very interesting "feature".
> I have a photo in jpeg format, and when I navigate to the folder, which
> contains it, in the thumbnail view everyting seem to be ok.
> I see the thumbnail of the photo. The default thumbnail size is quiet
> large
> (172x172).
> But when I start to make the thumnail smaller with the thumbnail size bar,
> and when the size of the thumbnail is smaller than 130x130, I can't
> beleive
> my eyes.
> In my thumnail I see details which aren't in the photo. The thumnail show
> me
> the probably original photo from which a part is cropped. And I have this
> cropped photo, but gwenview seem to be able to show me the original one.
> But when I open the photo into full screen, I see only the cropped part.
> I hope I succeded to write it clearly...
[snip]

Very interesting. I think I see what is happening. Let me explain:

Gwenview follows the Thumbnails Management Standard [1] which states that 
applications store their thumbnails in the ~/.thumbnail/ dir. If the application
wants a thumbnail smaller or equal to 128x128, it should generate a 128x128 
thumbnail and store it in ~/.thumbnail/normal/. If the thumbnail size is between 
128x128 and 256x256, the application should generate a 256x256 thumbnail and 
store it in ~/.thumbnail/large/.

Your JPEG probably contains what is called an EXIF thumbnail, generated by your 
digital camera. EXIF thumbnails are 160x120, so when you view images at 172x172, 
Gwenview does not use this EXIF thumbnail, it generates the thumbnail from the 
full image. When you reduce the thumbnail size to below 130x130, Gwenview 
generates a 128x128 thumbnail. This time it can use the EXIF thumbnail.

In your case, I guess the EXIF thumbnail is out-of-sync with the full image:
the original image must have been cropped by some software which kept the EXIF
thumbnail intact, but did not update it. So the bad news is that your original 
full image is lost. To verify this is the case, you can try the following: make 
a copy of your image, rotate it, then save. Gwenview will regenerate the EXIF 
thumbnail and the difference should not remain.

Aurélien

[1]: http://jens.triq.net/thumb-spec.php


-------------------------------------------------------------------------
Take Surveys. Earn Cash. Influence the Future of IT
Join SourceForge.net's Techsay panel and you'll get the chance to share your
opinions on IT & business topics through brief surveys -- and earn cash
http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV
_______________________________________________
Gwenview-general mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/gwenview-general