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diff --git a/Demo/tkinter/guido/electrons.py b/Demo/tkinter/guido/electrons.py
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+#!/ufs/guido/bin/sgi/tkpython
+# 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 4, maximum 15.
+#
+# 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.
+
+# This uses Steen Lumholt's Tk interface
+from Tkinter import *
+
+
+
+# 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,0,-1):
+ p = c.create_oval(x1, y1, x2, y2,
+ {'fill': 'red'})
+ self.pieces[i] = p
+ y1, y2 = y1 +2, y2 + 2
+ self.tk.update()
+
+ def random_move(self,n):
+ for i in range(1,n+1):
+ p = self.pieces[i]
+ c = self.canvas
+ import rand
+ x = rand.choice(range(-2,4))
+ y = rand.choice(range(-3,4))
+ c.move(p, x, y)
+ self.tk.update()
+ # Run -- never returns
+ def run(self):
+ while 1:
+ self.random_move(self.n)
+ self.tk.mainloop() # Hang around...
+
+# Main program
+def main():
+ import sys, string
+
+ # First argument is number of pegs, default 4
+ 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()
+
+