How to detect mouse inactivity

Question

I want to automatically dim keyboards light when its been inactive for some time. How can I detect inactivity time? I use archlinux, btw.

Answer 1

On Debian-based systems, there's a xprintidle command in the xprintidle package (from https://github.com/g0hl1n/xprintidle/) that prints the idle time in milliseconds on stdout.

$ sleep 2; xprintidle
1925

If you ltrace it, you'll see it uses XScreenSaverQueryExtension(), XScreenSaverQueryInfo() API like in other answers though also adds some workarounds to specific issues in corner cases with some servers.

Answer 2

Compiling and running this gets idle time in miliseconds

#include <X11/extensions/scrnsaver.h>
#include <stdio.h>

int main(void) {
    Display *dpy = XOpenDisplay(NULL);

    if (!dpy) {
        return(1);
    }

    XScreenSaverInfo *info = XScreenSaverAllocInfo();
    XScreenSaverQueryInfo(dpy, DefaultRootWindow(dpy), info);
    printf("%u\n", info->idle);

      return(0);
}

Answer 3

This is also implemented in C (with Makefile) at https://github.com/mjml/xidle.

It will provide hours, minutes, seconds, and milliseconds of idle time for shell scripts, with units/denominations selected by optional switches.