Demo/tkinter/guido/electrons.py

   1 #! /usr/local/bin/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 4, maximum 15.
   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 # This uses Steen Lumholt's Tk interface
  15 from Tkinter import *
  16
  17
  18
  19 # The graphical interface
  20 class Electrons:
  21
  22         # Create our objects
  23         def __init__(self, n, bitmap = None):
  24                 self.n = n
  25                 self.tk = tk = Tk()
  26                 self.canvas = c = Canvas(tk)
  27                 c.pack()
  28                 width, height = tk.getint(c['width']), tk.getint(c['height'])
  29
  30                 # Add background bitmap
  31                 if bitmap:
  32                         self.bitmap = c.create_bitmap(width/2, height/2,
  33                                                       {'bitmap': bitmap,
  34                                                        'foreground': 'blue'})
  35
  36                 self.pieces = {}
  37                 x1, y1, x2, y2 = 10,70,14,74
  38                 for i in range(n,0,-1):
  39                         p = c.create_oval(x1, y1, x2, y2,
  40                                                {'fill': 'red'})
  41                         self.pieces[i] = p
  42                         y1, y2 = y1 +2, y2 + 2
  43                 self.tk.update()
  44
  45         def random_move(self,n):
  46                 for i in range(1,n+1):
  47                         p = self.pieces[i]
  48                         c = self.canvas
  49                         import rand
  50                         x = rand.choice(range(-2,4))
  51                         y = rand.choice(range(-3,4))
  52                         c.move(p, x, y)
  53                 self.tk.update()
  54         # Run -- never returns
  55         def run(self):
  56                 while 1:
  57                         self.random_move(self.n)
  58                 self.tk.mainloop() # Hang around...
  59
  60 # Main program
  61 def main():
  62         import sys, string
  63
  64         # First argument is number of pegs, default 4
  65         if sys.argv[1:]:
  66                 n = string.atoi(sys.argv[1])
  67         else:
  68                 n = 30
  69
  70         # Second argument is bitmap file, default none
  71         if sys.argv[2:]:
  72                 bitmap = sys.argv[2]
  73                 # Reverse meaning of leading '@' compared to Tk
  74                 if bitmap[0] == '@': bitmap = bitmap[1:]
  75                 else: bitmap = '@' + bitmap
  76         else:
  77                 bitmap = None
  78
  79         # Create the graphical objects...
  80         h = Electrons(n, bitmap)
  81
  82         # ...and run!
  83         h.run()
  84
  85
  86 # Call main when run as script
  87 if __name__ == '__main__':
  88         main()
  89
  90