Kirby, I'm wondering if you have tried any of the cellular automata stuff using my graphics package. I suspect it would be dead simple, probably much eaiser than with POV-Ray or PIL. I haven't actually compared, so that's just a hunch.

I think that's an excellent idea. I've been wanting to include Tk in the mix for sure. Your idea to incorporate your stereo mode in the VPython stuff is also very interesting. I'm fantasizing about handing out stereographic glasses at OSCON. So just now I cut and pasted my PIL code and wrote it slightly differently for graphics.py. The graphics.py code is indeed somewhat simpler. This business about pixelsize (below) is a bit confusing, but basically I'm using "virtual pixels" with a canvas made up of those. This is because actual pixels tend to be rather tiny, and I often want to use "fat pixels" that are actually 2x2 or 3x3 or 4x4 regular pixels. Instead of using rectanglar fills, I just fill in a 3x3 pixel by hitting all 9 actual pixels individually. I should try it with rectangles. What I find with the current setup is that the PIL graphic, in building off screen until view time, develops quickly. The Tk-based implementation, on the other hand, in painting pixel by pixel, crawls along one row at a time, taking 15 minutes versus a few seconds. On the other hand, slow crawling has its appeal, i.e. one has time to think about how one row of cells determines the next, and so on. Here are my two canvas objects (PIL and graphics.py). I'll post the complete code for doing these 'New Kind of Science' cell maps once I clean it up a bit. Oh heck, I'll just toss nks.py to www.4dsolutions.net/ocn/python and revise it online. (for color coded view, in browser, use: http://www.4dsolutions.net/cgi-bin/py2html.cgi?script=/ocn/python/nks.py ) I don't mind showing some awkwardness (I have these reversals of binary strings going on because I wanted 110, say, to come out in binary going left to right, but for this Wolfram stuff, a right to left string would simplify the code -- I'll likely be revising accordingly). class Canvas(object): """ Uses PIL -- so far doesn't include option to save picture to disk """ def __init__(self, width, rows, pixelsize): self.pixelsize = pixelsize self.im = Image.new('RGB',(width*pixelsize, rows*pixelsize),(0,0,0)) self.draw = ImageDraw.Draw(self.im) def drawcell(self, thepoint): therow = thepoint[0]*self.pixelsize thecol = thepoint[1]*self.pixelsize for i in range(self.pixelsize): for j in range(self.pixelsize): self.draw.point((therow + i, thecol + j), fill=(255,255,0)) def showimage(self): self.im.show() class Canvas2(object): """ Uses graphics.py by Dr. John Zelle See: http://mcsp.wartburg.edu/zelle/python/ """ def __init__(self, width, rows, pixelsize): self.pixelsize = pixelsize self.c = GraphWin('NKS',width*pixelsize, rows*pixelsize) def drawcell(self, thepoint): therow = thepoint[0]*self.pixelsize thecol = thepoint[1]*self.pixelsize for i in range(self.pixelsize): for j in range(self.pixelsize): thepoint = Point(therow + i, thecol + j) thepoint.draw(self.c) Kirby PS: a win for me just now was getting Samba server on the laptop visible on the Windows network neighborhood via wifi. So I'm writing email on my XP desktop, while editing/uploading source code from the Linux laptop via the XP desktop. Fun fun.

From: edu-sig-bounces@python.org [mailto:edu-sig-bounces@python.org] On Behalf Of John Zelle Sent: Saturday, May 08, 2004 10:56 AM To: Kirby Urner; edu-sig@python.org Subject: Re: [Edu-sig] Re: Teaching graphics with Python (was Introductory high school programming)

For those of you working with VPython, if you've not tried it out yet, take a look at the stereoscopic mode. I contributed the main code for this in the fall of 2003. It's a spin-off from some VR work I've been doing with my students. The stereo mode allows you to take virtually any VPython program and turn it into true stereographic 3D. You can make the objects seem to jump right out of the screen at you. The stereo graphics are viewable in a variety of modes, but the really neat part is that you can do it with no special equipment at all. Just set the stereo mode to 'redblue' and you can use the cheap red-blue glasses that come with kids books and happy meals (and are used for viewing Mars photos). You can buy these glasses in bulk for pennies a piece and show true 3D programs to a roomful of people using a standard LCD projector. Kids love this!

Typically, making a program stereoscopic is as simple as doing: scene.stereo = 'redblue'

Hi John -- I wanted to thank you for this stereoscopic feature in VPython, and suggestion that I use it. I was sitting in Robin Dunn's tutorial on wxPython this Tuesday at OSCON when your suggestion drifted into my consciousness. I googled (OSCON had wifi) and lo and behold, found a 3D stereoscopy club and even a 3D *museum* right here in Portland ( http://www.cascade3d.org/ ). I emailed a guy and within 36 hours I had a whole stack of precisely those cheap red/blue glasses you described. I demoed quite a few things during my 45 minute talk, in addition to running through a bunch of slides in OpenOffice. The 3D thing came towards the end, and the audience (full room) went "ooooo" as the rhombic triacontahedron floated in front of them on the large screen, and "ahhhhhhh" as I rotated it and zoomed in to it. I also showed our cellular automata work using your graphics.py, which I mentioned, as well as holding up your book and talking about how important this was in the education side of things. My slides are here: http://www.4dsolutions.net/oscon2004/ (might be some minor problems if viewed in Windows, not sure (tried to make it work well in both, but kept finding little discrepancies going back and forth, and did all last minute editing on the Linux side)). People came up afterwards, and for the rest of the conference, saying how much they liked my talk. One guy said he was now persuaded to do Python in his CS1 next year (most of those present were not educators, but some advised on the side -- Dana Moore falls in this category (he showcased Python in Eclipse, so far mostly coded by : http://conferences.oreillynet.com/cs/os2004/view/e_spkr/524 ) The day before, I had a Middle Eastern lunch with your publisher, Jim Leisy (had never met him before) and Kevin Altis (main author of PythonCard and co-chair of the Python track at OSCON). Other highlights of the conference (from my point of view): --- Jim Hugunin showed the benchmarks for IronPython on the .NET framework -- it's working out very well (slower on Mono, but that project has more optimization to do). Jim starts work for Microsoft on Monday, so it'll be interesting to see under what terms further IronPython versions get out to our community http://conferences.oreillynet.com/cs/os2004/view/e_sess/5120 --- GvR's State of Python address introduced us to decorators, which offer a syntactic replacement for mymethod = staticmethod(mymethod) semantics in a class. He's going with @ (at sign), which he agrees looks unPythonic, but on the other hand there are good reasons for not inventing new key words. He knows this is controversial and is prepared to rip it out or change it if the community goes bananas. Decorators should be in the next alpha release of 2.4. He also talked about the new generator comprehensions and some of the subtleties involving late binding which could confuse people (more on that in a next post). http://conferences.oreillynet.com/cs/os2004/view/e_sess/4981 --- Alex Martelli gave a sophisticated presentation on Design Patterns, and as this preceded my talk, I was able to use 'façade' as a part of my patter (I build a façade, an adapter which limits the back end interface, into POV-Ray, VPython and the like). The other highlight re Alex was he and Anna just got married and shared slides and music from this event during the Lightning Talks. --- Michel Pelletier's talk overlapped a lot with Alex's. It was less about Zope3 and more about the importance of interfaces and adapters in Zope, PEAK and Twisted. He made a strong argument for bring interfaces into the syntax of Python in some way, so that Python would be able to compete effectively on these new multi-language VMs (.NET, Mono and Parrot). http://conferences.oreillynet.com/cs/os2004/view/e_sess/5298 --- I already mentioned the Python-in-Eclipse work, which is still beta, but coming along nicely. Andy McKay and Joel Burton did a very effective job presenting about Plone this time. Joel covered all the basics in a half day tutorial, and Andy focused on Archetypes, a technology for defining new data types within Plone without having to code too much. Andy, who has a new book out on Plone (Apress: http://www.apress.com/book/bookDisplay.html?bID=335 ), is the chief organizer behind VanPy (Python conference in Vancouver, BC) which starts like today or tomorrow. I'm not able to attend. Kirby

Kirby Urner wrote:

I'm finally making the time to work with VPython again. My previous high on that score was reading Arthur's Pygeo code (many versions ago) and trying to see how it all worked. These days, I'm just adapting what I've used to output to POV-Ray, and a lot of the same code over top. You might want to check out Ruth Chabay's code to emit POV-Ray code from a VPython scene. It is a little rough (I tried cleaning it up a bit once but abandoned the attempt before I got a really good slice of a torus), but could be the basis of a good movie preview setup that will let you tweak your movie viewpoints.

A motivation is 'Teaching Python with Graphics', which I'm suppose to present 45 minutes on at OSCON end of July. I'm planning to use my not-so-fancy laptop (1.2 Duron Compaq Presario 700) running Linux 2.4 (Mandrake 9.2) and Python 2.3, and graphics libraries (PIL, PyGame, VPython).

The focus is on smallish projects involving graphics and Python programming. For example, awhile back I posted re some of that Wolfram-style cellular automata stuff, using POV-Ray for output. I've since adapted that to PIL.

On the POV-Ray side, I do want to demo simple animation-building, though I haven't yet moved the whole stills-to-movie process to Linux (however, I'm confidant mplayer will both build and play the stuff).

-Scott David Daniels Scott.Daniels@Acm.Org