[Digikam-users] User experience (or bugs, hopes and wishes)

Birkir A. Barkarson birkirb at stoicviking.net
Mon Oct 2 16:08:31 BST 2006

Marcel Wiesweg wrote:
> http://bugs.kde.org/show_bug.cgi?id=127583
> (Comment #5)

Great.  The solution proposed sounds good.

>> A3.
>> On occasion when replacing comments only the IPTC fields are replaced
>> not the corresponding EXIF fields (eg. an image with a text scrambled as
>> per 2 displays the scrambled text in the comment/tag section. I copy the
>> text from the IPTC field and paste it into the comment section, it then
>> appears correctly in the comment section however the EXIF field still
>> contains the scrambled text).
> The "Comments" field of the "Comments/Tags" sidebar is primarily read from DB. 
> Only on import the value is read from the metadata, and the value is written 
> back to metadata when you change it, if it is enabled in the setup.

Like Pedro noted it would be great if the same would be done with the 
tag fields.

> As Gilles pointed out, the relevant code was written by me ;-)
> First, reading the comment. We need one comment, we have three fields. Order 
> is
> 1)JFIF comments section
> 2)EXIF UserComment
> 3)IPTC Caption
> So you get 3 only if 1+2 are empty.
> IPTC is converted from Latin1, that's easy.
> EXIF user comment _may_ provide charset info, that's handled by Exiv2, so if 
> it is marked as Unicode (UCS2 apparently, though you're right nothing in the 
> standard), Jis or ASCII, we take it.
> If not, we use the same as we do per default for the JFIF comments: Apply 
> basic autodetection.
> First, we use a KDE function to test if it is UTF8 (only KDE>=3.2). If not, we 
> use QTextCodec to look if it might be Latin1 or local encoding, and take the 
> best match.
> Writing the comment is much more easy. UTF8 for JFIF, if possible ASCII for 
> EXIF, otherwise UCS2, of course Latin1 for IPTC.
> I have tested this with exotic characters and all seems to work. Maybe the 
> UCS2 writing is broken? What do I need to do to reproduce the scrambled EXIF 
> encoding?

This does seem to be a most sensible approach.
Yes, I also assumed the EXIF Unicode should be UCS2.  I do recall that 
there was a bug in exiv2 a while back that caused this tag to be 
incorrect.  Although I haven't verified it, it is possible that I wrote 
those tags with that bug in effect.  For now lets assume it to be so.
A couple of issues remain.  The Exif user tag is not overwritten even if 
I change the comment.   I am still noting that the IPTC sidebar does not 
display correctly latin 1 characters (in the toolbar or if the info is 
copied to the clipboard, umlaut characters and so forth come out as 
question marks).

> Drag and drop works!
> It's currently _the_ way to do fast tagging of many pictures.

Cool. I can do it from the Tag Filters bar.  Brilliant (^^)b

> http://bugs.kde.org/show_bug.cgi?id=125387
> This requires a lot of thought.

Yes, this is a complex issue.  For me just doing the edits, saving them 
under a different name and having them stack under the same thumbnail 
would be good enough.

>> B5. Geotagging
>> I would love to be able to geotag inside digikam (using Goggle Map API
>> or something).  I saw that you have a plugin to correlate GPS data with
>> photo dates and that looks like something I want to take advantage of
>> but sometime you need to set or adjust the data manually so this ability
>> would be a real plus.

Gilles noted a kipi plugin for this.  I looked around.  Where can I 
get/build it from?

> This could be achieved by providing a setup option to exclude a hierarchy of 
> tags from being written to IPTC.

That would be swell, so multiple check in a hierarchy would save 
multiple tags.

> Thanks for your observations, your feedback is appreciated!

Most certainly welcome. I appreciate your efforts.



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