I have a 4K render of a simulation. I would like to composite the time for each frame on top of this render. The time to be rendered is a very small region, so I'd like to just crop that region to render and composite it. However, when using render regions, the output even with compositing is the same size.

Desired outcome
[![enter image description here](https://i.stack.imgur.com/Ihifx.jpg)](https://i.stack.imgur.com/Ihifx.jpg)

with render region

[![enter image description here](https://i.stack.imgur.com/Ez2Cx.png)](https://i.stack.imgur.com/Ez2Cx.png)

Is it possible to keep the rest of the image in the compositor without also cropping that?