[feverzsj]

x11 supports foreign window embedding. You can embed window from other application into your own window. That's why lots of mpv/vlc based players/editors don't work probably on wayland. The only way to achieve this on wayland is writing a custom compositor for the foreign window.

[l72]

I worked at a company that had a powerful legacy software that was meant to be configured once and run full screen.

At some point it needed a custom interface and the ability to reconfigure itself on the fly.

Adding in a GUI was not a reasonable option.

We ended up writing a GUI (in gtk) then using Xembed to embed the other process and communicate via a Unix socket.

What would have been a major rewrite (and likely a port to a different language) ended up being a few a days project and worked beautifully.

It really showed me how powerful X11 really was.