I would like to be able to see how much price has changed as a percentage versus previous bar close.

Is this possible with tradovate platform?

Thank you

Tradovate has a forum as well as discussion with tech support. I find they are pretty decent in answering questions. The forum contains a lot of community coded indicators, that are offered free, I wonder if you could find something like what you need there.
If not l know of a British Java coder, who is rather expensive at 150/hr, but he does good work. I can pass you his email.
All the best.