Re: [Gimp-developer] GIMP 2.9 XCF files and digiKam, gnome file browsers, etc

[Michael Natterer <mitch gimp org>]

On Tue, 2016-03-15 at 13:18 -0400, Elle Stone wrote:
> On 03/15/2016 10:51 AM, Kevin Payne wrote:
> > A very quick bit of rummaging round in source code leads me to
> > libgimpthumb\gimpthumb-utils.c
> >
> > Where it shows a fall-back if the thumbnails directory cannot be
> > created - it uses the tmp dir instead.
> >
> > Kevin
> Hmm, 
> https://specifications.freedesktop.org/thumbnail-spec/thumbnail-spec-
> latest.html#DIRECTORY 
> says the "normal" place for the thumbnail directory is 
> $XDG_CACHE_HOME/thumbnails/ and the "normal" location for 
> $XDG_CACHE_HOME is /$HOME/.cache.
>
> For whatever reason on my computer $XDG_CACHE_HOME is set to 
> /tmp/elle/.cache. So that's probably why GIMP is writing thumbnails
> to 
> the tmp folder.

You should fix that. Whatever is setting your XDG_CACHE_GOME to
/tmp/something is doing so wrongly, or at least not sanely :)

> If I start GIMP by adding the line:
>
> export XDG_CACHE_HOME=/home/elle/.cache
>
> then GIMP saves thumbnails to /home/elle/.cache/thumbnails.
>
> The thumbnail contains information that points to the corresponding
> XCF 
> file, for example:
>
> Description : Thumbnail of 
> file:///home/elle/edit/digiKam/working/080810-2252-1855-house-
> rainbow.xcf
> Software : GIMP 2.9.3
> Thumb URI : 
> file:///home/elle/edit/digiKam/working/080810-2252-1855-house-
> rainbow.xcf
>
> digiKam doesn't offer the option of adding a hidden folder to the
> database.
>
> Copying the thumbnail folder to a folder that digiKam monitors and 
> trying to open the correspoinding XCF file by opening the the
> thumbnail 
> just opens the thumbnail itself, not the XCF file.
>
> Are there any image/file browsers that can use the uri location 
> information in the thumbnail to open the corresponding XCF file
> rather 
> than the actual thumbnail png?
>
> I mean besides Nautilus. I don't want to install Nautilus on my
> computer 
> as it would mean making considerable changes to my Gentoo
> installation.

We use the folders specified in the freedektop thumbnail
managing spec, that's not going to change. You should file
bugs against desktop components that don't follow the
standard.

> As an aside, 
> https://specifications.freedesktop.org/basedir-spec/basedir-spec-late
> st.html 
> says $XDG_CACHE_HOME is for "user-specific non-essential (cached)
> data".
>
> It seems to me that the thumbnails that make it possible to browse
> one's 
> XCF files don't count as "non-essential". As it is, for the
> thumbnails 
> to be useful I'd have to use GIMP to recreate thumbnails for the 500
> or 
> so XCF files currently indexed by digiKam, and that would take an 
> enormouse amount of time to accomplish.

Thumbnails are by definition non-essential because they can be
recreated, and that's why they live in ~/.cache, you only need
to make sure your cache is at the persistent default location.

> Thumbnail browsing is at best a temporary and fragile workaround for 
> using an image DAM software like digiKam, that can make its own 
> thumbnails (except for GIMP 2.9 XCF files), or at least can read a 
> thumbnail already embedded in the image file.
>
> Are GIMP 2.9 XCF files saved to disk with embedded thumbnails?

That's on the TODO, but there are so many things on the TODO...

Regards,
--Mitch