[Digikam-users] How to remove "left behind" tag tree

[Jean-François Rabasse]

On Thu, 25 Oct 2012, Remco Viëtor wrote:

> One of the problems you face in correcting this behaviour is that when you
> make any change in the tag tree, potentially ALL your images (or sidecars)
> will have to be rewritten. If you are doing some extensive re-organisation
> of the tree, this can happen multiple times. So simply synchronising the
> changes with the file metadata can get very, very slow (not to mention risk
> of write errors, but for that we have backups, in theory...). It will also
> feel very slow: you have a number of changes in mind, but after every chance
> you'll have to wait while Digikam updates the affected files

I agree. And more, aside from « extensive re-organisation » of tags, even
the simple task of documenting new images leads to multiple metadata 
updates. E.g. on a single image :
  - geolocating then clicking Apply --> write to image or sidecar
  - setting a title or caption, then Apply --> write
  - rating, --> write

etc.

Even if update time for a single image isn't that great (today, but
probably Nikon users remember the time where a buggy libexiv2 took about
10 seconds per file to rewrite Makernotes :-), it's not really optimal.


> I think something like this asks for a kind of 'maintenance mode', where
> changes are put in a queue, and when you exit the maintenance mode, all
> changes are made in batch (to both database and images). If you cancel
> maintenance, no changes will happen.

Indeed. A pseudo workaround is to disable all writing (the Metadata settings
folder, uncheck all options « Save Image tags to...», « Save caption and
title...», etc.) before working.
Then images edition, documentation, tagging can occur in database only mode.
When done, recheck on the desired write options, then run albums level
commands, « Write metadata to images... »
(Then go for a coffee:-)

But, instead of checking off (and on later) several write options, a kind
of maintenance mode could be a simple flag, or checkbox, « Delay metadata 
writing ». AKO global write option.
Or another entry in the Metadata writing mode menu, « Write nothing »,
thant could be selected before extesive works, and set again later.
Perhaps, this could go on a Wishlist ?

BTW: geolocation seems to always write (to image or sidecar, depending of
the metadata writing mode) upon Apply. I don't see exactly the interest
of writing a picture location in a sidecar file only. As it's standard
Exif data, GPSsubIFD, this will prevent any coordinates aware application
(e.g. web services as GPS Visualizer) to work with the image :-(

But it could be really bothering for those of users that don't like DK to
write into images files, to select « Write to image file », before 
geolocating, then switch back to « Write to sidecar file only » before
editing a title, etc. Plus the potential risk for mistakes.
I'd really be interested in reading users experience.

Regards,
Jean-François