A Bash script which bounches a terminal (`cmatrix -bau5`) around the screen for screensaver purposes.

matrixBounce.sh

#!/bin/bash

##
## CONFIGURATION (Edit at will)
## 
screenw=1280
screenh=1024
speed=2 # the amount of pixels to move the window by
debug=0 # level 0-2


##
## GLOBALS (Don't edit unless you know what you're doing)
##

go=0
xo=900
yo=400
wo=350
ho=270

dB=1
dR=1


function matrixBounce() {
    
    g=$go
    x=$xo
    y=$yo
    w=$wo
    h=$ho


    while [[ 1 ]]; do
	cT=0
	cL=0
	cB=0
	cR=0
	


	# detect collisions
	[[ $y -lt 1 ]] && cT=1
	[[ $x -lt 1 ]] && cL=1
	[[ $(($y+$h)) -gt $screenh ]] && cB=1
	[[ $(($x+$w)) -gt $screenw ]] && cR=1

	
	# if there was a collision, redirect
	[[ $cT -eq 1 ]] && let dB=1
	[[ $cL -eq 1 ]] && let dR=1
	[[ $cB -eq 1 ]] && let dB=0
	[[ $cR -eq 1 ]] && let dR=0
	   


	# debug
	if [[ $debug -ge 1 ]]; then
            if [[ $dB -eq 1 && $dR -eq 1 ]]; then echo 'down right 🢆'; fi
	    if [[ $dB -eq 0 && $dR -eq 1 ]]; then echo 'up   right 🢅'; fi
	    if [[ $dB -eq 1 && $dR -eq 0 ]]; then echo 'down left  🢇'; fi
	    if [[ $dB -eq 0 && $dR -eq 0 ]]; then echo 'up   left  🢄'; fi
	    if [[ $debug -ge 2 ]]; then
		echo "dR=$dR dB=$dB cT=$cT cL=$cL cB=$cB cR=$cR y=$y x=$x y+h=$(($y+$h)) x+w=$(($x+$w)) screenw=$screenw"
	    fi
	fi

	
	# based on the new direction, set next position
	if [[ $dB -eq 1 ]]; then
	    let y=y+$speed
	else
	    let y=y-$speed
	fi

	if [[ $dR -eq 1 ]]; then
	    let x=x+$speed
	else
	    let x=x-$speed
	fi

	# move the window to the next position
	wmctrl -F -r MatrixView -e $g,$x,$y,$w,$h
	sleep 0.01

    done

}

# greets https://www.linuxquestions.org/questions/programming-9/bash-detecting-ctrl-c-being-pressed-785518-print/
function trapeze() {
    
    echo "Thanks for playing!"
    # reset MatrixView to home position 
    # @todo make this dynamically set on startup
    wmctrl -F -r MatrixView -e $go,$xo,$yo,$wo,$ho
    exit 0
}


trap trapeze SIGINT
matrixBounce