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      1 #!/usr/bin/env python
      2 # life.py -- A curses-based version of Conway's Game of Life.
      3 # Contributed by AMK
      4 #
      5 # An empty board will be displayed, and the following commands are available:
      6 #  E : Erase the board
      7 #  R : Fill the board randomly
      8 #  S : Step for a single generation
      9 #  C : Update continuously until a key is struck
     10 #  Q : Quit
     11 #  Cursor keys :  Move the cursor around the board
     12 #  Space or Enter : Toggle the contents of the cursor's position
     13 #
     14 # TODO :
     15 #   Support the mouse
     16 #   Use colour if available
     17 #   Make board updates faster
     18 #
     19 
     20 import random, string, traceback
     21 import curses
     22 
     23 class LifeBoard:
     24     """Encapsulates a Life board
     25 
     26     Attributes:
     27     X,Y : horizontal and vertical size of the board
     28     state : dictionary mapping (x,y) to 0 or 1
     29 
     30     Methods:
     31     display(update_board) -- If update_board is true, compute the
     32                              next generation.  Then display the state
     33                              of the board and refresh the screen.
     34     erase() -- clear the entire board
     35     makeRandom() -- fill the board randomly
     36     set(y,x) -- set the given cell to Live; doesn't refresh the screen
     37     toggle(y,x) -- change the given cell from live to dead, or vice
     38                    versa, and refresh the screen display
     39 
     40     """
     41     def __init__(self, scr, char=ord('*')):
     42         """Create a new LifeBoard instance.
     43 
     44         scr -- curses screen object to use for display
     45         char -- character used to render live cells (default: '*')
     46         """
     47         self.state = {}
     48         self.scr = scr
     49         Y, X = self.scr.getmaxyx()
     50         self.X, self.Y = X-2, Y-2-1
     51         self.char = char
     52         self.scr.clear()
     53 
     54         # Draw a border around the board
     55         border_line = '+'+(self.X*'-')+'+'
     56         self.scr.addstr(0, 0, border_line)
     57         self.scr.addstr(self.Y+1,0, border_line)
     58         for y in range(0, self.Y):
     59             self.scr.addstr(1+y, 0, '|')
     60             self.scr.addstr(1+y, self.X+1, '|')
     61         self.scr.refresh()
     62 
     63     def set(self, y, x):
     64         """Set a cell to the live state"""
     65         if x<0 or self.X<=x or y<0 or self.Y<=y:
     66             raise ValueError, "Coordinates out of range %i,%i"% (y,x)
     67         self.state[x,y] = 1
     68 
     69     def toggle(self, y, x):
     70         """Toggle a cell's state between live and dead"""
     71         if x<0 or self.X<=x or y<0 or self.Y<=y:
     72             raise ValueError, "Coordinates out of range %i,%i"% (y,x)
     73         if self.state.has_key( (x,y) ):
     74             del self.state[x,y]
     75             self.scr.addch(y+1, x+1, ' ')
     76         else:
     77             self.state[x,y] = 1
     78             self.scr.addch(y+1, x+1, self.char)
     79         self.scr.refresh()
     80 
     81     def erase(self):
     82         """Clear the entire board and update the board display"""
     83         self.state = {}
     84         self.display(update_board=False)
     85 
     86     def display(self, update_board=True):
     87         """Display the whole board, optionally computing one generation"""
     88         M,N = self.X, self.Y
     89         if not update_board:
     90             for i in range(0, M):
     91                 for j in range(0, N):
     92                     if self.state.has_key( (i,j) ):
     93                         self.scr.addch(j+1, i+1, self.char)
     94                     else:
     95                         self.scr.addch(j+1, i+1, ' ')
     96             self.scr.refresh()
     97             return
     98 
     99         d = {}
    100         self.boring = 1
    101         for i in range(0, M):
    102             L = range( max(0, i-1), min(M, i+2) )
    103             for j in range(0, N):
    104                 s = 0
    105                 live = self.state.has_key( (i,j) )
    106                 for k in range( max(0, j-1), min(N, j+2) ):
    107                     for l in L:
    108                         if self.state.has_key( (l,k) ):
    109                             s += 1
    110                 s -= live
    111                 if s == 3:
    112                     # Birth
    113                     d[i,j] = 1
    114                     self.scr.addch(j+1, i+1, self.char)
    115                     if not live: self.boring = 0
    116                 elif s == 2 and live: d[i,j] = 1       # Survival
    117                 elif live:
    118                     # Death
    119                     self.scr.addch(j+1, i+1, ' ')
    120                     self.boring = 0
    121         self.state = d
    122         self.scr.refresh()
    123 
    124     def makeRandom(self):
    125         "Fill the board with a random pattern"
    126         self.state = {}
    127         for i in range(0, self.X):
    128             for j in range(0, self.Y):
    129                 if random.random() > 0.5:
    130                     self.set(j,i)
    131 
    132 
    133 def erase_menu(stdscr, menu_y):
    134     "Clear the space where the menu resides"
    135     stdscr.move(menu_y, 0)
    136     stdscr.clrtoeol()
    137     stdscr.move(menu_y+1, 0)
    138     stdscr.clrtoeol()
    139 
    140 def display_menu(stdscr, menu_y):
    141     "Display the menu of possible keystroke commands"
    142     erase_menu(stdscr, menu_y)
    143     stdscr.addstr(menu_y, 4,
    144                   'Use the cursor keys to move, and space or Enter to toggle a cell.')
    145     stdscr.addstr(menu_y+1, 4,
    146                   'E)rase the board, R)andom fill, S)tep once or C)ontinuously, Q)uit')
    147 
    148 def keyloop(stdscr):
    149     # Clear the screen and display the menu of keys
    150     stdscr.clear()
    151     stdscr_y, stdscr_x = stdscr.getmaxyx()
    152     menu_y = (stdscr_y-3)-1
    153     display_menu(stdscr, menu_y)
    154 
    155     # Allocate a subwindow for the Life board and create the board object
    156     subwin = stdscr.subwin(stdscr_y-3, stdscr_x, 0, 0)
    157     board = LifeBoard(subwin, char=ord('*'))
    158     board.display(update_board=False)
    159 
    160     # xpos, ypos are the cursor's position
    161     xpos, ypos = board.X//2, board.Y//2
    162 
    163     # Main loop:
    164     while (1):
    165         stdscr.move(1+ypos, 1+xpos)     # Move the cursor
    166         c = stdscr.getch()                # Get a keystroke
    167         if 0<c<256:
    168             c = chr(c)
    169             if c in ' \n':
    170                 board.toggle(ypos, xpos)
    171             elif c in 'Cc':
    172                 erase_menu(stdscr, menu_y)
    173                 stdscr.addstr(menu_y, 6, ' Hit any key to stop continuously '
    174                               'updating the screen.')
    175                 stdscr.refresh()
    176                 # Activate nodelay mode; getch() will return -1
    177                 # if no keystroke is available, instead of waiting.
    178                 stdscr.nodelay(1)
    179                 while (1):
    180                     c = stdscr.getch()
    181                     if c != -1:
    182                         break
    183                     stdscr.addstr(0,0, '/')
    184                     stdscr.refresh()
    185                     board.display()
    186                     stdscr.addstr(0,0, '+')
    187                     stdscr.refresh()
    188 
    189                 stdscr.nodelay(0)       # Disable nodelay mode
    190                 display_menu(stdscr, menu_y)
    191 
    192             elif c in 'Ee':
    193                 board.erase()
    194             elif c in 'Qq':
    195                 break
    196             elif c in 'Rr':
    197                 board.makeRandom()
    198                 board.display(update_board=False)
    199             elif c in 'Ss':
    200                 board.display()
    201             else: pass                  # Ignore incorrect keys
    202         elif c == curses.KEY_UP and ypos>0:            ypos -= 1
    203         elif c == curses.KEY_DOWN and ypos<board.Y-1:  ypos += 1
    204         elif c == curses.KEY_LEFT and xpos>0:          xpos -= 1
    205         elif c == curses.KEY_RIGHT and xpos<board.X-1: xpos += 1
    206         else:
    207             # Ignore incorrect keys
    208             pass
    209 
    210 
    211 def main(stdscr):
    212     keyloop(stdscr)                    # Enter the main loop
    213 
    214 
    215 if __name__ == '__main__':
    216     curses.wrapper(main)
    217