This might sound confusing, but this is what I'm trying to achieve:
I already have an algorithm in my mind, where we simply detect the corners touching the Cartesian rectangle and calculate the bounds from there, but I just wanted to see if there were more clever ways of solving this problem.
It's not a homework
I don't want a full answer, just a pointer, wondering if there are more clever ways of solving it.
The isometric object can be a rectangle, it's width and height might differ.