Because it also has to simulate keypresses as the result of gestures. I don't think the Wayland world has an official way for non-compositor programs to send keypresses to any surface the program itself owns, in the name of security.
Which is a shame, I do dearly like xdotool etc. There should be a way to satisfy both security and function, a way to whitelist or permit special apps.
I bet they will fix that somehow with Wayland. Tools like xdotool are pretty popular and if they don't support it officially, someone will come up with a hack around it.
Nice choice of words here. The whole reason why it isn't supported is to prevent being hacked in the first place. X11 has no security whatsoever. Every window can read/spy/mess with any other.
I guess only window managers / compositors will have enough permission to do this level of automation.
IIRC, not quite. with X11, every program that shares a root window can see the keypresses etc.
Typically a root windows is the same as a screen, but i don't think there is anything that claim this to be a set in stone rule.
But as is typical of Linux GUI devs, they much rather hack on the new shiny than try to maintain the existing stuff. And the new shiny these days is to put everything on the GPU.
fusuma is configured with a text file and touchegg seems to have a GUI.
fusuma autoinstalls, but you must have Ruby (which should be there on every Ubuntu). touchegg must be compiled and the installation sequence failed for me, but as I wrote, it seems it won't work anyway on 16.04.
If you're a Ruby developer using rvm or the like, you must remember which Ruby version you installed fusuma into, or tweak its startup script to load the right one.
Such as dragging a window using a three finger swipe?