A Standard for Thumbnailers

[Erlend Davidson]

I have been writing small thumbnailers for the filemanager Thunar 
(http://thunar.xfce.org/index.html).  I like the way Thunar uses a 
.desktop file to invoke external programs and scripts (like 'convert' 
from imagemagick) to generate the thumbnails for various formats.  How 
this works is detailed at: 
http://thunar.xfce.org/documentation/C/customizing-thunar.html#thumbnailers.

A lot of programs generate thumbnails these days, and there exists a 
clear standard as to where these thumbnails should be placed so that 
different applications can share thumbnails.  However there is no such 
standard for thumbnailers: different applications each come with there 
own host of small thumbnailer applications.

The thumbnailers for Thunar register themselves with Thunar by 
installing a .desktop file under /usr/local/share/thumbnailers.  This 
contains a special key like:

 X-Thumbnailer-Exec=/usr/local/bin/eps-thumbnailer %i %o %s

where %i is the input file, %o the output file, and %s the size of the 
output.  This is explained in more detail in the link above.

This seems to me to be a very good system - I am wondering if it, or 
something similar, could be used as a standard to allow applications to 
share thumbnailers?

Here are some links to relevant posts on the Tracker search tool 
(http://www.tracker-project.org/) mailing list:
http://mail.gnome.org/archives/tracker-list/2007-January/msg00032.html
http://mail.gnome.org/archives/tracker-list/2007-January/msg00031.html
http://mail.gnome.org/archives/tracker-list/2007-January/msg00029.html


Erlend