Did you try what is detailed in this answer to a similar question? https://unix.stackexchange.com/a/183941/141220
You have Arch and an uncommon wm so you probably knew you had to do some hacking on your own.
reposting here, this comes from the link above, if it works don't forget to thank the user mikeserv too, as I'm mostly a messenger here.
The following will probably work for you:
#!/bin/sh
unset X Y; sleep 1
eval "$(xdotool getmouselocation -shell 2>/dev/null)"
for n in X Y; do : "$(($n-=$n>25?25:$n))"; done
xwd -root -silent |
xv - -crop "$X" "$Y" 50 50 \
-geometry "50x50+$X+$Y" \
-nodecor -viewonly -rv -quit
It depends on the three utilities xv, xwd, and xdotool. The first two are very common X utilities, and the third I'm reasonably sure you already have.
After sleeping one second, xdotool writes the mouse's current coordinates to its stdout in an eval-friendly -shell format like:
X=[num]
Y=[num]
windowID=[num]
eval sets the shell variables accordingly, and the for loop subtracts half of the soon-to-be-displayed image's size from each of $X and $Y's values or, if either value is less than 25, sets them to 0.
xwd dumps the root window over a pipe to xv, which crops around the mouse location to an image size of 50x50 and displays a negative of the image under the current mouse cursor in a little window sans any window manager decorations.
The end result is something like this:
...though I guess my mouse cursor doesn't show-up in screen shots. Rest assured, though, it was right over the white box there when I took the picture.
You can see in the image how I also wrote it as a shell function and backgrounded it. It is mainly for that reason there is a sleep in there at all - pressing the RETURN key will scroll the terminal if you're already at the bottom, and xwd was fast enough to grab its picture of the screen before the terminal scrolled - which would offset my negative in the image a little and I didn't like it.
Anyway, because xv is run with both the -viewonly and -quit switches, it will disappear as soon as a mouse-button is clicked or a keyboard key is pressed - but will remain until you do either.
Undoubtedly you could do much more elaborate things with ImageMagick or even xv alone as well - but I just did a little negative box under the mouse cursor. You can find the xv docs here and the docs for xwd in man xwd.
