[Thunar-dev] Problem with thumbnails

Erlend Davidson E.R.M.Davidson at sms.ed.ac.uk
Sun Feb 17 12:37:36 CET 2008

> Hehe, high-performance and large images? It is possible to load and
> store thumbnails inside the EXIF data AFAIK. I imagine large JPEGs
> will sometimes have that. The thumbnailer could check for that and
> fail otherwise.
Most images produced by a digital camera will have a thumbnail stored in 
the exiv data (it's the same thumbnail the camera uses to display the 
image on the LCD).  Thunar already extracts those (this came in 0.8.0, 
and gives very good performance).

> Or, the thumbnailer should gracefully fail when overwhelmed, and let
> Thunar use the generic icon for that mime type.
Well the problem is how to tell when you're overwhelmed?  Difference 
people have difference ideas of when a thumbnailer should and shouldn't 
run... I think most people would say don't run if it's going to use swap 
space, I would say don't run if it's going to adversely affect the 
apparent responsiveness of the operating environment.  If you're running 
a remote filesystem (fusesmb / sshfs) then the file-sizes which are safe 
to thumbnail change dramatically.

One or two of the Thunar-thumbnailers (the goodies.xfce.org ones) will 
refuse to run on large files.  For example the xmgrace thumbnailer (.agr 
files) won't run on files > 50MB, because it would actually have to load 
all of that into memory.  But as I said before you cannot apply the same 
logic to video files (they aren't loaded into memory).

Having thumbnailers try and run on large files just to fail is bad... 
for the 3 seconds when it's loading the performance of the user's 
computer will be affected.


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