Some applications place informational text over their icons in the Launcher.
For example, Thunderbird shows the unread message count, and Update Manager shows the number of updates available and a progress bar. The image shows these two examples:
I have created some Bash scripts that use yad
(a Zenity fork), which adds an icon to the Launcher while running.
I would like to know how I can create my own information overlay within my script for those icons.
This is for Python, perhaps something can be found for another language..
From the update-manager source, UnitySupport.py:
You need to:
to get Unity support.
You can then define a function:
Also, to show urgency(shake the icon),
or to create a progressbar,
where progress is from 0 to 100. You can then use:
to show the progressbar and use False instead of True to hide it.
As always, searching the source of a program that does what you are trying to do can be worthwhile.
These are subject to change at anytime. You can also see the Unity API.
I don't think you can do it through bash directly, you have to interface with the API. There are python bindings through gi introspection. See this page which has python and vala examples: https://wiki.ubuntu.com/Unity/LauncherAPI