xcf thumbnail image file support?

xcf thumbnail image file support?

[joakim]

Hello list,

Has anyone started work on displaying xcf thumbnail previews for
emacs?

xcf is the image file format used by the Gimp(gnu image manipulation
program). 

-- 
Joakim Verona

Re: xcf thumbnail image file support?

[Jason Rumney]

joakim@verona.se wrote:
> Hello list,
>
> Has anyone started work on displaying xcf thumbnail previews for
> emacs?
>   
Do xcf files contain jpeg or png thumbnails within their metadata, or
would we need another library to decode the image? If its the former,
then a general image metadata mode to handle metadata and thumbnails in
jpeg (exif) and tiff files as well as xcf might be a good approach.

Re: xcf thumbnail image file support?

[joakim]

Jason Rumney <jasonr@gnu.org> writes:

> joakim@verona.se wrote:
>> Hello list,
>>
>> Has anyone started work on displaying xcf thumbnail previews for
>> emacs?
>>   
> Do xcf files contain jpeg or png thumbnails within their metadata, or
> would we need another library to decode the image? If its the former,
> then a general image metadata mode to handle metadata and thumbnails in
> jpeg (exif) and tiff files as well as xcf might be a good approach.

I' not quite sure but it seems gimp saves thumbnails in ~/.thumbnails,
which aparently is a form of standard:
http://jens.triq.net/thumbnail-spec/

So the original question should be rephrased as:
Is there work in progress to make emacs support the "thumbnail
managing standard"?

-- 
Joakim Verona

Re: xcf thumbnail image file support?

[Mathias Dahl]

> So the original question should be rephrased as:
> Is there work in progress to make emacs support the "thumbnail
> managing standard"?

It's been over a year since I looked into this now, so my memory is a
bit fuzzy, but it seems I/we made some changes to Tumme, now
Image-Dired, to support this standard.

Quickly browsing the code now it seems basic support was added. You
can set `image-dired-thumbnail-storage' to 'standard to test it:

(defcustom image-dired-thumbnail-storage 'use-image-dired-dir
  "How to store image-dired's thumbnail files.
Image-Dired can store thumbnail files in one of two ways and this is
controlled by this variable.  \"Use image-dired dir\" means that the
thumbnails are stored in a central directory.  \"Per directory\"
means that each thumbnail is stored in a subdirectory called
\".image-dired\" in the same directory where the image file is.
\"Thumbnail Managing Standard\" means that the thumbnails are
stored and generated according to the Thumbnail Managing Standard
that allows sharing of thumbnails across different programs."
  :type '(choice :tag "How to store thumbnail files"
                 (const :tag "Thumbnail Managing Standard" standard)
                 (const :tag "Use image-dired-dir" use-image-dired-dir)
                 (const :tag "Per-directory" per-directory))
  :group 'image-dired)

Basically if you use this setting, Image Dired and programs adhering
to the standard should be able to share thumbnails. If you browse a
dir in Dired for which you know thumbnails have been created under
~/.thumbnails, Image Dired should not need to create its own, when
commands like C-t d is used, for example. I am not up to date on what
things would be needed to be fully compliant though.

Try it out and we might find some nice bugs to iron out :)

/Mathias

Re: xcf thumbnail image file support?

[David Kastrup]

"Mathias Dahl" <mathias.dahl@gmail.com> writes:

> Quickly browsing the code now it seems basic support was added. You
> can set `image-dired-thumbnail-storage' to 'standard to test it:
>
> (defcustom image-dired-thumbnail-storage 'use-image-dired-dir
>   "How to store image-dired's thumbnail files.
> Image-Dired can store thumbnail files in one of two ways and this is
> controlled by this variable.  \"Use image-dired dir\" means that the
> thumbnails are stored in a central directory.  \"Per directory\"
> means that each thumbnail is stored in a subdirectory called
> \".image-dired\" in the same directory where the image file is.
> \"Thumbnail Managing Standard\" means that the thumbnails are
> stored and generated according to the Thumbnail Managing Standard
> that allows sharing of thumbnails across different programs."
>   :type '(choice :tag "How to store thumbnail files"
>                  (const :tag "Thumbnail Managing Standard" standard)
>                  (const :tag "Use image-dired-dir" use-image-dired-dir)
>                  (const :tag "Per-directory" per-directory))
>   :group 'image-dired)

The DOC string refers to the customize display rather than the actual
values to set this variable to.  That makes it useless as programming
documentation for the variable.  Please use the actual values in the
description while keeping the customize tags: it is obvious which of
the described behaviors they refer to.

-- 
David Kastrup, Kriemhildstr. 15, 44793 Bochum