Demo/tkinter/guido/electrons.py

   1 #! /usr/bin/env python
   2
   3 # Simulate "electrons" migrating across the screen.
   4 # An optional bitmap file in can be in the background.
   5 #
   6 # Usage: electrons [n [bitmapfile]]
   7 #
   8 # n is the number of electrons to animate; default is 30.
   9 #
  10 # The bitmap file can be any X11 bitmap file (look in
  11 # /usr/include/X11/bitmaps for samples); it is displayed as the
  12 # background of the animation.  Default is no bitmap.
  13
  14 from Tkinter import *
  15 import random
  16
  17
  18 # The graphical interface
  19 class Electrons:
  20
  21         # Create our objects
  22         def __init__(self, n, bitmap = None):
  23                 self.n = n
  24                 self.tk = tk = Tk()
  25                 self.canvas = c = Canvas(tk)
  26                 c.pack()
  27                 width, height = tk.getint(c['width']), tk.getint(c['height'])
  28
  29                 # Add background bitmap
  30                 if bitmap:
  31                         self.bitmap = c.create_bitmap(width/2, height/2,
  32                                                       bitmap=bitmap,
  33                                                       foreground='blue')
  34
  35                 self.pieces = []
  36                 x1, y1, x2, y2 = 10,70,14,74
  37                 for i in range(n):
  38                         p = c.create_oval(x1, y1, x2, y2, fill='red')
  39                         self.pieces.append(p)
  40                         y1, y2 = y1 +2, y2 + 2
  41                 self.tk.update()
  42
  43         def random_move(self, n):
  44                 c = self.canvas
  45                 for p in self.pieces:
  46                         x = random.choice(range(-2,4))
  47                         y = random.choice(range(-3,4))
  48                         c.move(p, x, y)
  49                 self.tk.update()
  50
  51         # Run -- allow 500 movemens
  52         def run(self):
  53                 try:
  54                         for i in range(500):
  55                                 self.random_move(self.n)
  56                 except TclError:
  57                         try:
  58                                 self.tk.destroy()
  59                         except TclError:
  60                                 pass
  61
  62
  63 # Main program
  64 def main():
  65         import sys, string
  66
  67         # First argument is number of electrons, default 30
  68         if sys.argv[1:]:
  69                 n = string.atoi(sys.argv[1])
  70         else:
  71                 n = 30
  72
  73         # Second argument is bitmap file, default none
  74         if sys.argv[2:]:
  75                 bitmap = sys.argv[2]
  76                 # Reverse meaning of leading '@' compared to Tk
  77                 if bitmap[0] == '@': bitmap = bitmap[1:]
  78                 else: bitmap = '@' + bitmap
  79         else:
  80                 bitmap = None
  81
  82         # Create the graphical objects...
  83         h = Electrons(n, bitmap)
  84
  85         # ...and run!
  86         h.run()
  87
  88
  89 # Call main when run as script
  90 if __name__ == '__main__':
  91         main()