#! /usr/bin/env python # Simulate "electrons" migrating across the screen. # An optional bitmap file in can be in the background. # # Usage: electrons [n [bitmapfile]] # # n is the number of electrons to animate; default is 30. # # The bitmap file can be any X11 bitmap file (look in # /usr/include/X11/bitmaps for samples); it is displayed as the # background of the animation. Default is no bitmap. from Tkinter import * import random # The graphical interface class Electrons: # Create our objects def __init__(self, n, bitmap = None): self.n = n self.tk = tk = Tk() self.canvas = c = Canvas(tk) c.pack() width, height = tk.getint(c['width']), tk.getint(c['height']) # Add background bitmap if bitmap: self.bitmap = c.create_bitmap(width/2, height/2, bitmap=bitmap, foreground='blue') self.pieces = [] x1, y1, x2, y2 = 10,70,14,74 for i in range(n): p = c.create_oval(x1, y1, x2, y2, fill='red') self.pieces.append(p) y1, y2 = y1 +2, y2 + 2 self.tk.update() def random_move(self, n): c = self.canvas for p in self.pieces: x = random.choice(range(-2,4)) y = random.choice(range(-3,4)) c.move(p, x, y) self.tk.update() # Run -- allow 500 movemens def run(self): try: for i in range(500): self.random_move(self.n) except TclError: try: self.tk.destroy() except TclError: pass # Main program def main(): import sys, string # First argument is number of electrons, default 30 if sys.argv[1:]: n = string.atoi(sys.argv[1]) else: n = 30 # Second argument is bitmap file, default none if sys.argv[2:]: bitmap = sys.argv[2] # Reverse meaning of leading '@' compared to Tk if bitmap[0] == '@': bitmap = bitmap[1:] else: bitmap = '@' + bitmap else: bitmap = None # Create the graphical objects... h = Electrons(n, bitmap) # ...and run! h.run() # Call main when run as script if __name__ == '__main__': main()