Update #2: Added another version posSave which writes the dialog placement information to a file in the users appdata folder when it’s closed, that way it will reopen in the same place. [The dialog has to be closed to save it’s placement, closing Aseprite as a whole will not trigger the save.]
Update #1: Added an offset version see below for demo gif [glitchy look is from my gif recorder not the script, sorry don’t have time to re-record it].
Made a quick and dirty little tool out of a slightly modified script:
A toolbar script that lets you align selected or the layer content if nothing is selected to one of nine regions.