Home | History | Annotate | Download | only in demo 
      1 #!/usr/bin/env python3
      2 
      3 """
      4 Animated Towers of Hanoi using Tk with optional bitmap file in background.
      5 
      6 Usage: hanoi.py [n [bitmapfile]]
      7 
      8 n is the number of pieces to animate; default is 4, maximum 15.
      9 
     10 The bitmap file can be any X11 bitmap file (look in /usr/include/X11/bitmaps for
     11 samples); it is displayed as the background of the animation.  Default is no
     12 bitmap.
     13 """
     14 
     15 from tkinter import Tk, Canvas
     16 
     17 # Basic Towers-of-Hanoi algorithm: move n pieces from a to b, using c
     18 # as temporary.  For each move, call report()
     19 def hanoi(n, a, b, c, report):
     20     if n <= 0: return
     21     hanoi(n-1, a, c, b, report)
     22     report(n, a, b)
     23     hanoi(n-1, c, b, a, report)
     24 
     25 
     26 # The graphical interface
     27 class Tkhanoi:
     28 
     29     # Create our objects
     30     def __init__(self, n, bitmap = None):
     31         self.n = n
     32         self.tk = tk = Tk()
     33         self.canvas = c = Canvas(tk)
     34         c.pack()
     35         width, height = tk.getint(c['width']), tk.getint(c['height'])
     36 
     37         # Add background bitmap
     38         if bitmap:
     39             self.bitmap = c.create_bitmap(width//2, height//2,
     40                                           bitmap=bitmap,
     41                                           foreground='blue')
     42 
     43         # Generate pegs
     44         pegwidth = 10
     45         pegheight = height//2
     46         pegdist = width//3
     47         x1, y1 = (pegdist-pegwidth)//2, height*1//3
     48         x2, y2 = x1+pegwidth, y1+pegheight
     49         self.pegs = []
     50         p = c.create_rectangle(x1, y1, x2, y2, fill='black')
     51         self.pegs.append(p)
     52         x1, x2 = x1+pegdist, x2+pegdist
     53         p = c.create_rectangle(x1, y1, x2, y2, fill='black')
     54         self.pegs.append(p)
     55         x1, x2 = x1+pegdist, x2+pegdist
     56         p = c.create_rectangle(x1, y1, x2, y2, fill='black')
     57         self.pegs.append(p)
     58         self.tk.update()
     59 
     60         # Generate pieces
     61         pieceheight = pegheight//16
     62         maxpiecewidth = pegdist*2//3
     63         minpiecewidth = 2*pegwidth
     64         self.pegstate = [[], [], []]
     65         self.pieces = {}
     66         x1, y1 = (pegdist-maxpiecewidth)//2, y2-pieceheight-2
     67         x2, y2 = x1+maxpiecewidth, y1+pieceheight
     68         dx = (maxpiecewidth-minpiecewidth) // (2*max(1, n-1))
     69         for i in range(n, 0, -1):
     70             p = c.create_rectangle(x1, y1, x2, y2, fill='red')
     71             self.pieces[i] = p
     72             self.pegstate[0].append(i)
     73             x1, x2 = x1 + dx, x2-dx
     74             y1, y2 = y1 - pieceheight-2, y2-pieceheight-2
     75             self.tk.update()
     76             self.tk.after(25)
     77 
     78     # Run -- never returns
     79     def run(self):
     80         while 1:
     81             hanoi(self.n, 0, 1, 2, self.report)
     82             hanoi(self.n, 1, 2, 0, self.report)
     83             hanoi(self.n, 2, 0, 1, self.report)
     84             hanoi(self.n, 0, 2, 1, self.report)
     85             hanoi(self.n, 2, 1, 0, self.report)
     86             hanoi(self.n, 1, 0, 2, self.report)
     87 
     88     # Reporting callback for the actual hanoi function
     89     def report(self, i, a, b):
     90         if self.pegstate[a][-1] != i: raise RuntimeError # Assertion
     91         del self.pegstate[a][-1]
     92         p = self.pieces[i]
     93         c = self.canvas
     94 
     95         # Lift the piece above peg a
     96         ax1, ay1, ax2, ay2 = c.bbox(self.pegs[a])
     97         while 1:
     98             x1, y1, x2, y2 = c.bbox(p)
     99             if y2 < ay1: break
    100             c.move(p, 0, -1)
    101             self.tk.update()
    102 
    103         # Move it towards peg b
    104         bx1, by1, bx2, by2 = c.bbox(self.pegs[b])
    105         newcenter = (bx1+bx2)//2
    106         while 1:
    107             x1, y1, x2, y2 = c.bbox(p)
    108             center = (x1+x2)//2
    109             if center == newcenter: break
    110             if center > newcenter: c.move(p, -1, 0)
    111             else: c.move(p, 1, 0)
    112             self.tk.update()
    113 
    114         # Move it down on top of the previous piece
    115         pieceheight = y2-y1
    116         newbottom = by2 - pieceheight*len(self.pegstate[b]) - 2
    117         while 1:
    118             x1, y1, x2, y2 = c.bbox(p)
    119             if y2 >= newbottom: break
    120             c.move(p, 0, 1)
    121             self.tk.update()
    122 
    123         # Update peg state
    124         self.pegstate[b].append(i)
    125 
    126 
    127 def main():
    128     import sys
    129 
    130     # First argument is number of pegs, default 4
    131     if sys.argv[1:]:
    132         n = int(sys.argv[1])
    133     else:
    134         n = 4
    135 
    136     # Second argument is bitmap file, default none
    137     if sys.argv[2:]:
    138         bitmap = sys.argv[2]
    139         # Reverse meaning of leading '@' compared to Tk
    140         if bitmap[0] == '@': bitmap = bitmap[1:]
    141         else: bitmap = '@' + bitmap
    142     else:
    143         bitmap = None
    144 
    145     # Create the graphical objects...
    146     h = Tkhanoi(n, bitmap)
    147 
    148     # ...and run!
    149     h.run()
    150 
    151 
    152 # Call main when run as script
    153 if __name__ == '__main__':
    154     main()
    155