[Digikam-devel] Storage of digiKam Tags path (again)...

[Gilles Caulier]

I just finalized the code to set and get the IPTC XML data set into digiKam
core.

The XML data format is given below :

<?xml version="1.0" encoding="UTF-8"?>
<digikamproperties>
 <comments value="A cool photo from Adrien..." />
 <date value="2006-11-23T13:36:26" />
 <rating value="4" />
 <tagslist>
  <tag path="gilles/adrien/testphoto" />
  <tag path="monuments/Trocadero/Tour Eiffel" />
  <tag path="City/Paris" />
 </tagslist>
</digikamproperties>

Gilles

2007/3/14, Gilles Caulier <caulier.gilles at gmail.com>:
>
> After investaguations, i can said than Exif is not the good place to do
> it.
>
> IPTC/IIM sound fine to store this data, especially because storing Exif to
> TIFF/DNG file is the hell with libtiff (Andreas, i'm waiting to have Exiv2
> TIFF writting (:=))))... but libtiff can store IPTC very well.
>
> Other stuff is to convert pictures using ImageMagick. Like ImageMagick use
> libtiff internally, we can only use IPTC to not lost these data...
>
> I will store a zlib compressed byte array of XML data (not real XMP, just
> an simple XML schema to store digiKam properties).
>
> I have take a look witch IPTC/IIM tags are free for use, reading ExifTool
> database and others web page.
>
> The "Iptc.Application2.0x00ff" sound good. Like IPTC will not be used
> anymore with new photo management application, the chance to have this tag
> used by another software is very limited.
>
> This is an example of the content of the uncompressed tag :
>
> <!DOCTYPE XMLImageProperties>
> <imageproperties version="1" client="digikam" encoding="UTF-8" />
> <properties comments="Ceci est un test en utilisant des caractères
> accentués..." rating="4" date="2006-11-23T13:36:26" >
>  <tagslist>
>   <tag path="Communications" />
>   <tag path="aaa/bbb/ccc" />
>   <tag path="bbb/ccc/ddd" />
>   <tag path="bbb/ccc/ddd/Paris" />
>   <tag path="bbb/ccc/ddd/Paris/bjwdfkjhjbdqjfihbdqfdwbf" />
>   <tag path="City" />
>   <tag path="City/London" />
>   <tag path="City/New York" />
>   <tag path="City/Paris" />
>  </tagslist>
> </properties>
>
> For this example the compressed data use only 374 bytes in the tag. It's
> small (better than XMP can use for the same content)
>
> What do you think about ?
>
> Gilles
>
>
> 2007/3/12, Gilles Caulier <caulier.gilles at gmail.com>:
> >
> > Right. Thanks for this tips. I will do some investigations.
> >
> > Gilles
> >
> > 2007/3/12, Andreas Huggel < ahuggel at gmx.net>:
> > >
> > > On Monday 12 March 2007 00:29, Gilles Caulier wrote:
> > > > Andreas,
> > > >
> > > > if you talking about Interroperability directory, witch tag number
> > > > you recommend to use ?
> > > >
> > > > In Exiftool database, i can see 5 tags :
> > > >
> > > > 0x0001, 0x0002, 0x1000, 0x1001, and 0x1002.
> > > >
> > >
> > > The Exiv2 taglist has the same 5 IOP tags. The Exif standard actually
> > > only has tag 0x0001. Thus, the good thing about this directory is that
> > > it's not widely used, so there is less potential for a conflict;
> > > choose
> > > a random number and chances are good that nobody else will use the
> > > same
> > > tag. On the other hand, maybe because the IOP directory is not widely
> > > used, there is a possibility that it is not well supported by other
> > > software. So you may want to test if applications that attempt to
> > > write
> > > Exif tags manage to write the IOP directory as well.
> > >
> > > -ahu.
> > > _______________________________________________
> > > Digikam-devel mailing list
> > > Digikam-devel at kde.org
> > > https://mail.kde.org/mailman/listinfo/digikam-devel
> > >
> >
> >
>
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