Well, OK, but usually I want to go the other way. How about something that can take a drawing produced in some sort of reasonable drawing tool and produce ASCI

Well, OK, but usually I want to go the other way. How about something that can take a drawing produced in some sort of reasonable drawing tool and produce ASCII art that I can include in some kind of ASCII-only file (like program source.) Originating a drawing in ASCII-art is about as fun as a poke in the eye with a sharp stick. Certainly, there is value on ASCII-art to nice-graphics mark-up, but only to the extent that the ASCII-art is used as an intermediate, human readable, common-demoninator storage format. Authoring in ASCII-art just needs to stop.