Backplotter

[Ray Henry <rehenry-at-up.net>]

Hey Arne and other visualizers!

I was thinking about Jon's 4th axis post and reading some of the files in
emctask and I'm wondering if we could use the step and direction pulses
that are sent to the parallel port, for a stepper machine, to do the
backplotting for us.

If we opened a channel in tk to the parallel port and just added or
subtracted each pulse from a tcl variable we'd get an imaginary machine
accessible within the tcltk language.  We would just have to program the tk
canvas widget to turn on a pixel for each step pulse.  Set up three views
to the machine with zoom and scan and we'd have a rough version of a
backplotter. 

We'd have to do a workaround for servo driven machines but i think Fred
plans to allow for both types of drives at the same time.  Maybe something
could be worked out there -- or step and direction pulses could be sent
directly to emcsh and we could work from there.

What do you think?

Happy new year!

Ray

(Arne - Don't worry about me.  Ian said he was putting on flame proof
underwear to protect his most important parts.  I've got a whole body suit
-- besides, I like the wheelchair idea.)