Add a countdown as a line

I don’t know if I’m posting in the right topic, but, as stated in my google play review, I would like a line that is basically a count down (or a count up? haha); I set a starting time, and and end time, and the bar slowly fills up until it reaches the end time; then it resets to 0, next day same.
basically, something like this app, but in powerline format.
I understand if the devs refuse to add it tho, it’s a whimp of mine, but I would appreciate it and it would make me buy pro to support the app (gotta pay the devs somehow :P)