Displaying a Classification Banner at the top of each computer monitor in Gnome Desktop

Question

I work in an environment where we have to have a security classification banner displayed at the top of each monitor on our Gnome Desktops. Currently, I am using a Perl/Tk window to display the classification of the system. However, that window cannot be moved because of the way it is built (no decorations) and occasionally overlays open windows making it difficult for users to manage those windows.

I would like to be able to do something different, but I'm not sure where to start. Three ideas I have are this:

1. An icon or something in the Top Bar showing the classification
2. A banner, like the Top Bar, that sits above the Top Bar
3. A window, like I already have, but relocatable

I figure the first option would be easiest, but since the Top Bar isn't shown on every monitor, that may not be the best option. I don't even know if the second option is even possible. The third option would require me to use something other than Perl/Tk but that's the only language I'm fluent in at the moment.

So I'm looking for suggestions or examples or Gnome extensions I can use to solve this problem.

Thanks.

Answer 1

There is a classification-banner python utility at https://github.com/fcaviggia/classification-banner. It's no longer maintained, but we've been using it without change for a few years now. It's OK. One problem is that it doesn't "shrink" the desktop screen, so application windows can overlap it; it's set to Always On Top, but it would be nicer if it actually couldn't be overlaid at all.

A simple solution, of sorts, would be to change the desktop background image. This can have issues if you're displaying on multiple resolutions (I don't know if Gnome supports SVG for such purposes) and of course it can be obscured by windows covering it.

Older versions of Gnome let you create multiple bars that worked perfectly, but that disappeared - along with many other customizations - in Gnome 3.