It's just a string like any other. You can build it however you want.

printf "%-".$width."s ", $AoA[$x][$y]; 
printf "%-${width}s ", $AoA[$x][$y];
[download]

You can also use "*":

printf "%-*s ", $width, $AoA[$x][$y]; 
printf "%*s ", -$width, $AoA[$x][$y];
[download]