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Subject: 
Re: Building a Postscript printer?
Newsgroups: 
lugnet.robotics
Date: 
Sat, 24 Jun 2000 00:07:23 GMT
Viewed: 
626 times
  
Well, I wasn't really thinking that I would cram the whole
Postscript interpreter into the RCX. Instead, I was going
to structure it as a Postscript interpreter (running on
the host PC) talking to a rendering device (the RCX).
So the RCX itself need only implement a few simple
functions (pen up/down, move, turn etc) while the
Postscript interpreter on the PC figures out the
sequence of commands to feed it.

Due to the limitations of the RCX as a renderer, not
all Postscript programs are going to be printable. So
we also some kind of a filter which only allows "well-formed"
Postscript programs. E.g., embedded bitmaps would be
a no-no. And fonts would have to be simple. Lines might
have limitations on their slopes. Dunno what else.

After an initial implementation, more and more could be
crammed into the RCX to simplify the job of the host
filter and interpreter. In theory.

Is it possible for a host PC program to communicate with
a downloaded program which is running on the RCX? Two-way
communication, that is.

Manoj


In lugnet.robotics, Brian Connors writes:
--- Manoj Plakal <plakal@no-spam.cs.wisc.edu> wrote:

Hello,

I'm completely new to the Lego Mindstorms scene. I
was
thinking about getting RIS 1.5  this summer, and one
cool
project I was thinking about was building a robot
that could be used as a printer or plotter of vector
graphics
e.g., Postscript, or the Scalable Vector Graphics
(SVG)
Markup Language from www.w3.org.

The system would consist of a main driver running on
a PC controlling the robot which would basically
hold the pens and which would move over chart paper.

Anyone tried anything similar? Any comments on
feasibility? Is it possible for the driver on the PC
to
continually talk to the RCX after the initial
download
of the RCX program?

You might want to take a look at the Postscript
Language Definition first. You're not gonna be fittin'
no PostScript 3 interpreter in no 32K, yo.

However, a PostScript language subset isn't such a bad
idea; what you'd be creating would be the basic
PostScript interpreter (in LegOS or some such), with a
simple implementation of the language and primitives
to control either (low-level) the RCX itself or
(high-level) draw the picture. Either way you're
talking about a firmware replacement, not a
quick-and-dirty RCXcode hack.

/Brian

=====
--



Message has 1 Reply:
  Re: Building a Postscript printer?
 
(...) [snip] (...) I might suggest taking a look at the Postscript code generated by AdobeStreamline. I used it in a Vector Terminal application and it worked quite well. Postcript header and most of the eps can be ignored and just process the (...) (24 years ago, 24-Jun-00, to lugnet.robotics)

Message is in Reply To:
  Re: Building a Postscript printer?
 
(...) You might want to take a look at the Postscript Language Definition first. You're not gonna be fittin' no PostScript 3 interpreter in no 32K, yo. However, a PostScript language subset isn't such a bad idea; what you'd be creating would be the (...) (24 years ago, 23-Jun-00, to lugnet.robotics)

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