[hacknews] pen-up fix to hpgl software

henry@utzoo.UUCP (Henry Spencer) (07/27/84)

Another (!) minor bug fix to the HP plotter plot(3) library:  the closepl()
routine now puts the pen up before parking it.  This means that the plotter
is left in the "pen up" state, so when the next job tells it to pick up a
pen, it doesn't pick it up and then promptly make a dot on the paper where
the last plot ended up!  (Note that this didn't always occur, because some
of the plotter instructions -- e.g. labelling, which is often the last
thing in a plot -- don't leave the pen down unless it was down beforehand.
I happened to have plots where the last thing drawn was a vector, and when
I was doing repeated testing this problem showed up.)
-- 
				Henry Spencer @ U of Toronto Zoology
				{allegra,ihnp4,linus,decvax}!utzoo!henry