2015 February 24
Such screencasting happens over the AirPlay protocol. The Linux box is then the AirPlay sender, of course. This shouldn’t be hard since Apple wants to make it easy for people to show stuff on Apple TVs! If weird embedded devices can do it, Linux should be able to too.
Important: As of my last experiences (~2018), this method only works when running X Windows — not Wayland. So, on modern Linux desktops, you might need to log out of your Wayland session and start a new session choosing X Windows mode. Then after you’re done, you’ll probably want to log out and in again, re-activating Wayland, since the session manager remembers which system you were using.
java -cp 'jmdns.jar:airplay.jar' com.jameslow.AirPlay
which took a little bit of time but more or less worked. Couldn’t see mouse cursor, window management was a litle wonky, etc. I feel like I should be able to find something that works at least a bit better.