Dunno if Dungeon Painter Studio is the same thing but that is still availlable on Steam.AutoRealm looks super complicated, and really ugly. Definitely not.
No, I think it must have been a very old windows-based version of Dungeon Painter that I had. Unfortunately, it seems, I no longer have it.
I also use Tiamat The Tile Mapper from time to time. It's good for simple things. The interface is a little clunky.