#3 Add a thumbnailer file

The thumbnailer file is used by thumbnail generators, like file managers. By installing this file, users will be able to get thumbnails of JPEG2000 files.

This is a great addition, thanks! This probably works great on Debian, but unfortunately I can't get it to work on Arch.

First, it seems Archlinux puts thumbnailers in /usr/share/thumbnailers, but the install script seems to be installing in /usr/local/share/thumbnailers/?

Second, I see the file it generates on my system looks like this:

[Thumbnailer Entry]
TryExec=/usr/local/bin/gdk-pixbuf-thumbnailer
Exec=/usr/local/bin/gdk-pixbuf-thumbnailer -s %s %u %o
MimeType=image/jp2;image/jpm;image/jpx;image/jpeg2000;image/x-jp2-codestream;

But, /usr/local/bin/gdk-pixbuf-thumbnailer doesn't exist on arch, it seems it's just at /usr/bin/gdk-pixbuf-thumbnailer

Maybe a meson bug?

I use XFCE, and it also seems Thunar is unable to create thumbnails for some reason. Might be related to this though: https://gitlab.xfce.org/xfce/tumbler/-/issues/27

The default prefix for Meson is /usr/local, so it will install things under that. The thumbnailers directory is typically discovered through the $XDG_DATA_DIRS and $XDG_DATA_HOME environment variables from the XDG base directories specification.

But, /usr/local/bin/gdk-pixbuf-thumbnailer doesn't exist on arch, it seems it's just at /usr/bin/gdk-pixbuf-thumbnailer

Ah, yes, that's a good point. I operated under the assumption that a system installation is going to use /usr as a prefix.

Sadly, gdk-pixbuf does not export the location of the thumbnailer program in the pkg-config file. I can fix that upstream, but it'll take a bit to be available in the various Linux distributions.

For the time being, I can fix it manually:

• search for gdk-pixbuf-thumbnailer in the $PATH and use that as the Exec value
• add a build option in the meson_options.txt to let packagers override the location and name of the gdk-pixbuf-thumbnailer binary from the default, like the build already does for the gdk-pixbuf-query-loaders tool.

Actually, seems I was uneducated. Reading the guidelines for packaging with meson for Arch they specifically state I need to pass --prefix=/usr to meson. Doing so makes it install in the correct location using your first commit. Might want to revert or force push or something, sorry!

I can't get it to work in Thunar, Konqueror, Nautilus, or Dolphin. PCManFM, however, worked for some reason.

Merged manually.