Violating XDG base directory standard

[stephenstrangeMD]

Gnome and applications are moving the to XDG-basedir specification . Would be nice to get the currently violating ~/.imagej folder XDG compliant. In that way we can keep our $HOME's a little bit cleaner.

Resources:

• https://wiki.archlinux.org/index.php/XDG_Base_Directory
• https://maex.me/2019/12/the-power-of-the-xdg-base-directory-specification/
• https://wiki.gnome.org/Initiatives/GnomeGoals/XDGConfigFolders

[stephenstrangeMD]

To start the discussion, the following seem to be more inline with the specs:

~/.imagej/IJ_Prefs.txt  -> ${XDG_CONFIG_HOME:-~/.config}/imagej/IJ_Prefs.txt
~/.imagej/plugins/      -> ${XDG_DATA_HOME:-~/.local/share}/imagej/plugins/

[ctrueden]

Thanks @stephenstrangeMD, I agree. CC @rasband.

At minimum, changes would need to happen here:

https://github.com/imagej/imagej1/blob/1e601bc96421ad532b0205a8d007386ffa47509a/ij/Prefs.java#L306-L313

Splitting content across ~/.config versus ~/.local/share and/or ~/.cache would require more effort.

There are also other related SciJava projects that we should update, including scijava/jgo and scijava/scijava-grab.