I think people are dying for a web-based compositor in other host language environments, but don't know how to elucidate this concept because they don't know anything else.

There’s actually quite a lot of interesting work going on in that general space, has been in various forms for some years. A couple that immediately spring to mind:

• Azul <https://azul.rs/> builds on WebRender, as used in Firefox. I haven’t looked at it for a few years, but it looks to have grown quite interesting now.

• Blitz <https://github.com/DioxusLabs/blitz> is based on from-scratch implementations of CSS layout and rendering, and wgpu rendering. It’s not usable yet, but is a very interesting concept. If one happens to be familiar with React Native: it’s kinda like that, or React Native Web.

React Native Web… eh, it has a potential place. Maybe like scratching your left ear with your right arm, because your left arm is partially paralysed, or something!

The weakness is interop with C/C++. There's a new Java FFI in the works that makes that a lot better by auto-generating bindings from header files and avoiding JNI, but it hasn't shipped as stable yet. It's usable. You just have to accept that the API might change a bit.

You can also compile the whole thing to a native library that doesn't use a typical JVM at all. Memory usage and startup time is a lot better if you do that. You can also expose functions natively to C, or bind to C natively, using a different approach.

If I were to do use that approach I'd write a generic binding layer that lets you connect JavaFX observables to their C++ or Rust-side data structures. FX has an architecture that's very based on observable variables, which all have a uniform API, so if you can control those from the native side then you can do anything. Either updating state objects that are then in turn connected to UI objects, or directly updating UI.