[SOLVED] Thumbnail problem in Mint 13 Xfce

[eraser1171]

I've been having a strange problem with Mint Xfce Maya eversince I did a clean install on my laptop : despite the fact that I did check "display thumbnails" in Thunar preferences, the file manager was never able to show any thumbnails (no matter what file type). I did check that tumbler was installed (which is there by default, I believe). Thinking that it might have something to do with Thunar, and after I noticed that I did miss some features in Thunar that are present in other file managers, I ended up installing Caja tonight. While Caja runs perfectly well, it won't show any thumbnails either. Any idea where I should look for a solution? Right now, I'm pretty much convinced that the file managers aren't to blame, but I really don't know where to dig to find the problem and solution to it...

[eraser1171]

Bump

I'll add that I've checked that all dependencies needed for thumbnail generation either by Thunar or Caja have been installed. I run Xfce 4.10, and I enabled backport repositories to get the latest Caja (version 1.4). The problem still persists. Anyone has any idea what are the common tools for thumbnails generation between Caja and Thunar? I've tried deleting the .cache/thumbnails and .thumbnails directories and recreating them, and the problem still persists. And to cover the obvious, thumbnails have been enabled for both Thunar and Caja in their respective "preference" menus. Don't know if this also helps, but I've read somewhere that gThumb will use available thumbnails for picture visualization when available in the cached thumbnails directory (as generated by Nautilus or other file managers), and if not will generate thumbnails that will then be cached. When I use gThumb, I do get thumbnails, but these need to be re-generated everytime I use gThumb. I'm thinking I might have a problem with the cache, but I have no clue how to solve this (and I did try to enlist my good friend Google for help, but nothing seems to work right now).

Anyone has any idea?

[twolf]

Even supposing that nothing should be missing for Thunar in a clean installation, like you said, did you already try searching at the following link ?

http://goodies.xfce.org/projects/thunar-plugins/thunar-thumbnailers

Bye

[eraser1171]

Thanks for you answer twolf. Package xfce4-goodies, which includes thunar-thumbnailers, is installed according to synaptic.

[twolf]

Did you try watching any errors opening thunar by a terminal while you are browsing the files you expect some thumbnails to be shown ?

In order to do so you should first kill the thunar proccess already running in daemon mode, otherwise typing thunar won't fork it from the terminal.
That proccess could have a capitalized T (don't ask me why ):

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wolf@wolf-laptop ~ $ ps -ef | grep -i thunar
wolf     28036 27966  0 19:01 ?        00:00:00 Thunar --sm-client-id 25e7f5bfa-6eee-4941-8838-44698ccc48f0 --daemon
wolf     28290 28216  0 19:01 pts/0    00:00:00 grep --colour=auto -i thunar

Kill it and start one in deamon mode from your terminal:

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wolf@wolf-laptop ~ $ killall Thunar && thunar --daemon

Now leave that terminal opened: it should log any errors while you browse your files...

Bye

[eraser1171]

Not sure what I should be getting. Doing "thunar --daemon" in terminal seems to start a process (since trying to close the window will tell me that there is a process running), but does not launch any visible Thunar instance that I can use to browse files as I would normally get if I were simply typing "thunar" in terminal. Manually opening thunar afterwards does not seem to influence whatever should be happening in my terminal window. It just sits there and does nothing, with no text/error message appearing no matter how many folder I browse in Thunar.

However, if I open Thunar from command line simply by typing Thunar, Thunar does open and then multiple errors are recorded in the terminal window. Five errors seem to repeat themselves quite a lot :

(thunar:382): Gdk-CRITICAL **: IA__gdk_window_get_window_type: assertion `GDK_IS_WINDOW (window)' failed

(gthumb:406): GLib-GIO-CRITICAL **: g_file_info_set_icon: assertion `G_IS_FILE_INFO (info)' failed

(gthumb:406): GLib-GIO-CRITICAL **: g_file_info_set_display_name: assertion `G_IS_FILE_INFO (info)' failed

(gthumb:406): GLib-GObject-CRITICAL **: g_object_unref: assertion `G_IS_OBJECT (object)' failed

Error: Directory Canon with 6912 entries considered invalid; not read

The last one is quite puzzling. As far as I can tell, there is no "Canon" directory on my system! Caja can't find any directory name Canon, and searching for it in my home directory throught the find command in terminal generates the following message :

vinster171@vinster171-Compaq-Presario-CQ50-Notebook-PC ~ $ find $HOME -name Canon -type d
find: `/home/vinster171/.cache/thumbnails/normal': Permission denied

I hope this helps...

[twolf]

Doing "thunar --daemon" in terminal seems to start a process (since trying to close the window will tell me that there is a process running), but does not launch any visible Thunar instance that I can use to browse files as I would normally get if I were simply typing "thunar" in terminal

Yes, it's normal: starting as a deamon it stays in background and opens no instance unless it is asked by "thunar" command. It's the only way to hope to log any error because typing only "thunar" in terminal opens a window instance but "escapes" the terminal.

Anyway, I'm puzzled about the "permission denied" error from your find command, as it refers to a folder seemingly used for thumbnails and you should have access to that.
The default one used by Thunar is $HOME/.thumbnails, maybe $HOME/.cache/thumbnails is for Caja (I don't know it).

Posting the following could help, as I suspect you could have something wrong with permissions:

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ls -ld $HOME/.thumbnails

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ls -ld $HOME/.cache/thumbnails

Bye

[eraser1171]

Here's the output of these commands :

vinster171@vinster171-Compaq-Presario-CQ50-Notebook-PC ~ $ ls -ld $HOME/.thumbnails
lrwxrwxrwx 1 vinster171 vinster171 34 Dec 29 23:05 /home/vinster171/.thumbnails -> /home/vinster171/.cache/thumbnails
vinster171@vinster171-Compaq-Presario-CQ50-Notebook-PC ~ $ ls -ld $HOME/.cache/thumbnails
drwxr-xr-x 3 root root 4096 Dec 30 23:29 /home/vinster171/.cache/thumbnails

Not sure what that means thought. According to a website I got throught my good friend Google (http://earthen.tripod.com/linuxper.htm), I am guessing I might have some permission issues going on with the $HOME/.cache/thumbnails directory... Could a simple chmod solve this?

By the way, thanks a bunch for taking the time to help me out. It's much appreciated.

[twolf]

You're welcome

I think we found the problem.
/home/vinster171/.thumbnails in your case is just a link to /home/vinster171/.cache/thumbnails, that's ok.
But the owner of /home/vinster171/.cache/thumbnails is not you, it's root, and the folder has no write permission for others than root. Creating thumbnails means writing to that folder but you can't.
It's a problem of ownership rather than permissions, as you should be the owner of that kind of folders, so the proper action is an ownership changing by this command:

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sudo chown vinster171:vinster171 /home/vinster171/.cache/thumbnails

Normally you should be the owner of everything within your home folder. Something (Caja installation procedure ?) did some mess with file ownership.

Let me know if your problem is fixed.

[eraser1171]

Ownership changed (checked what the result was after doing a ls -ld command)... still not thumbnails. I did notice a change however : before, in Caja, instead of an image preview/thumbnail, I'd get a sort of "work in progress" image for each file as if Caja was actually trying to retrieve/generate thumbnails. Now, I only see the generic thumbnail that is associated with the file type. Nothing changed in Thunar.

I'm thinking the ownership problem for $HOME/.cache/thumbnails was indeed created when Caja was installed, as you pointed out. However, my thumbnail problem predates the installation of Caja. I'm a bit at a loss here... I still feel we've made some progress, but I have no clue what the next step is.

I have no clue of this might be related, but even before installing Caja, I had noticed that when I use gThumb to browse my picture folders, the software is able to spontaneously generate a thumbnail for every file, but those thumbnails don't seem to be stored anywhere since gThumb needs to regenerate them everytime I browse to a different folder inside the software. As an example, if I select my wallpaper folder inside gThumb, the software will generate the thumbnails. If I then navigate to another folder (still in the gThumb interface), and then come back to the wallpaper folder, the thumbnails are regenerated once more rather than simple retrieved from a store (that might be only a guess, but I feel like there's no improvement in the time it takes to show the thumbnails, which I guess should be the case of the thumbnails were simple retrived and not regenerated from scratch). Is that even possible?

[twolf]

If your problem predates the installation of Caja, this makes me suspect of a wider anomaly.
Two tests are worth to be done in your home folder, wether there are other files not owned by you or files whose owner does not have write permissions:

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find $HOME ! -user `whoami`
find $HOME ! -perm /u+w

If these commands return some file or folder, post an "ls -ld" of it.

Said that, I'm short of ideas but if I were you I would try the following procedure:

1) Remove Caja

2) Re-create the default configuration for thumbnail folder:

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rm $HOME/.cache/thumbnails
rm -fr $HOME/.thumbnails && mkdir $HOME/.thumbnails

3) Do a fresh re-installation of Thunar:

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sudo apt-get purge thunar && sudo apt-get install thunar

4) Try wether thumbnails work with thunar

5) Try possibly if something changes after re-installing Caja

[eraser1171]

SOLVED! Here's what happened when I ran the first command you posted :

vinster171@vinster171-Compaq-Presario-CQ50-Notebook-PC ~ $ ls -ld /home/vinster171/.cache/thumbnails/normal
drwx------ 2 root root 4096 Dec 30 23:29 /home/vinster171/.cache/thumbnails/normal

Basically, there was another folder inside the .cache/thumbnails for which ownership wThe other command you posted generated a somewhat puzzling result :as problematic. I ran chown as you showed me yesterday, and I now have thumbnails in both Thunar and Caja! My problem is solved, and I have learned a couple of very useful commands along the way that should prove useful in the future if I encounter other problems that are permission/ownership related! Thanks a lot once again, twolf!

[twolf]

Ah ah, ok !

Actually, it was much better using option -R :

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sudo chown -R vinster171:vinster171 /home/vinster171/.cache/thumbnails

to operate immediately recursively on all files and sub-folders.

Happy to be useful

Long live the penguin