David, It's been a while, but I finally got around to thinking about how I would properly implement something like MagicBaton in Python, and I've got a prototype that essentially works the way you describe. If you're interested, here's how to install and run the new code: - Install the latest version of MidiKinesis, available at http://www.math.tu-berlin.de/~brinkman/software/midikinesis/ Once you've unpacked the tarball, say 'make' in the midikinesis directory. - Install the Python Midi package. There's a link on the MidiKinesis page. I guess the easiest (but not the nicest) way to make this work is to simply dump the contents of the Python Midi package in the midikinesis directory. - Save the attached boaconductor.py in the midikinesis directory. Now find a MIDI file that you want to experiment with. I like Matthias Nagorni's MIDI files, available at http://sourceforge.net/project/showfiles.php?group_id=69130&package_id=… Just to make sure that your setup works, see whether you can play a MIDI files with the midiplayer.py, by saying python midiplayer.py file.mid After starting this program, you need to hook up the MIDI output ports of midiplayer.py to some synthesizer(s). I simply plug it into my digital piano. When that's done, hit return, and you should hear the piece. Now, to experiment with BoaConductor, you essentially do the same thing: python boaconductor.py file.mid Once again you need to hook up the MIDI output ports to some synthesizer(s), and then you can start directing by tracing out circles in the GUI of BoaConductor. Since this is just a proof of concept at this point, I have spent a lot of time on the user interface. In particular, right now any configuration has to be done in the code itself. Here are the parameters you may want to play with: - self.gain: This one lets you increase or decrease the number of quarters that one full revolution of the mouse corresponds to. - self.tempo and self.volume: These are objects that use an averaging process of sorts in order to remove the wobble that imprecise mouse motions tend to cause. They have some parameters that can be tweaked in order to make them more or less responsive. I put a comment in the code to this effect. (In case you're mathematically inclined, I'm using Kalman filters in order to remove wobble without incurring too much latency.) I'm also generating MIDI Master Volume messages based on the average radius of the circles you're drawing, but my piano seems to ignore them. It would be interesting to know whether they work on your side. I'd be interested to hear how you like the new gadget. As I said, it's very rough around the edges at the moment, but I think it shows that the general idea works. I'm also having a lot of fun with it. Any thoughts would be appreciated! Best, Peter On Thu, Jan 20, 2005 at 09:39:07AM +0200, David Baron wrote: --

#!/usr/bin/python # $Id: boaconductor.py,v 1.8 2005/06/19 17:57:52 brinkman Exp $ # Peter Brinkmann (brinkman(a)math.tu-berlin.de) from Tkinter import * from math import * import time from pyseq import * from midiplayer import * class SimpleKalman: def __init__(self, p, q, r): self.p=p self.q=q self.r=r self.x=None def next(self, x): if self.x is None: self.x=x return x pm=self.p+self.q k=pm/(pm+self.r) self.x+=k*(x-self.x) self.p=(1-k)*pm return self.x class BoaConductor(Frame): def __init__(self, tune, parent): self.seq=PlaySeq(tune) self.ev=snd_seq_event() Frame.__init__(self, parent) self.pack(fill=X, expand=YES) self.master.title('BoaConductor') self.height=self.width=500 self.xc, self.yc=self.width/2, self.height/2 self.x=self.y=None self.gain=1 self.phi0=4*pi self.callhandle=None self.paused=0 self.start() self.cv=Canvas(self, width=self.width, height=self.height, relief=SUNKEN, borderwidth=2) self.cv.pack() Button(self, text='Restart', command=self.start).pack() Button(self, text='Quit', command=self.cleanup).pack() self.cv.bind('<Enter>', self.handleEntrance) self.cv.bind('<Motion>', self.handleMotion) self.cv.create_line(self.xc, 0, self.xc, self.height) self.cv.create_line(0, self.yc, self.width, self.yc) def cleanup(self): self.seq.handleSignal() self.quit() def handleEntrance(self, e): self.x, self.y=e.x, e.y def setTempoMTV(self, omega): self.seq.q.setMidiTempoValue(int(2e6*pi/omega/self.gain)) def setVolume(self, d): vol=min(16384, int(d/(.7*self.width)*32768)) for p in self.seq.oports: self.ev.setMasterVolume(vol) self.seq.q.postEvent(self.ev, p, 0) def start(self): if not self.callhandle is None: self.after_cancel(self.callhandle) self.callhandle=None self.seq.q.stop() self.seq.panic() self.t=None self.phi=0 self.paused=0 self.tempo=SimpleKalman(1, 1e-5, .03) # the smaller the last value, # the more responsive the behavior (beware of wobble) self.volume=SimpleKalman(1, 1e-5, .01) def startQueue(self): self.seq.play() def angle(self, x, y): return atan2(y-self.yc, x-self.xc) def distance(self, x, y): return sqrt((y-self.yc)**2+(x-self.xc)**2) def angleDiff(self, x0, y0, x1, y1): phi0, phi1=self.angle(x0, y0), self.angle(x1, y1) return min(abs(phi1-phi0), abs(phi1-phi0+2*pi), abs(phi1-phi0-2*pi)) def handleMotion(self, e): if not self.callhandle is None: self.after_cancel(self.callhandle) t=time.time() if self.t is None: self.t=t self.x, self.y=e.x, e.y return dphi=self.angleDiff(e.x, e.y, self.x, self.y) if self.phi<self.phi0 and self.phi+dphi>self.phi0: self.startQueue() dt=t-self.t self.setTempoMTV(self.tempo.next(dphi/dt)) self.setVolume(self.volume.next(self.distance(e.x, e.y))) if self.paused: self.paused=0 self.seq.q.cont() self.x, self.y=e.x, e.y self.t=t self.phi+=dphi self.after(1000, self.cv.delete, self.cv.create_oval(e.x-2, e.y-2, e.x+2, e.y+2, fill='red')) self.callhandle=self.after(250, self.pause) def pause(self): self.callhandle=None self.seq.q.stop() self.paused=1 if __name__=='__main__': if len(sys.argv)<2: fn='trio_es_2_nagorni.mid' else: fn=sys.argv[1] print 'hook up midi ports, draw circles' tune=MidiToAlsa(fn) BoaConductor(tune, Tk()).mainloop()