It appears that MiterJoin doesn't do anything at all. From reading the source code, if the Join style is not RoundJoin or BevelJoin, then the Joiner returned is the RoundJoiner. Although in my case, RoundJoin doesn't seem to work either (I always get a bevel).
Original issue reported on code.google.com by
ke...@sb.orgon 27 Oct 2013 at 10:22