I put canvas’s width and height into app state, and listen to size changes to update the state. Then redraws will happen automatically on resize

https://github.com/vlaaad/reveal/blob/master/src/vlaaad/reveal/output_panel.clj#L476

That makes sense. I am bit concerned about how smooth that will appear but since I am bouncing all the way to opengl and back anyway I don't think it can be butter smooth.

Does that coalesce rendering? For example does a single resize cause 2 render requests?

Yes, it appears like it does with batching descriptions. This is great.

Not sure I understand the question, but you can request rendering million times per second from multiple threads, and it should preform redraws once per frame from javafx ui thread

That's when using renderer abstraction

There's an example of that somewhere...

https://github.com/cljfx/cljfx/blob/master/examples/e24_concurrency.clj

That is what I was looking for. If a user starts resizing the window then you can easily end up with too many events to render and some level of coalescing makes sense. Sorry of all the detailed questions, I am also going through the code to see what is going on.