Demo/curses/life.py

   1 #!/usr/bin/env python
   2 # life.py -- A curses-based version of Conway's Game of Life.
   3 # Contributed by A.M. Kuchling <amk1@bigfoot.com>
   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 class LifeBoard:
  21     """Encapsulates a Life board
  22
  23     Attributes:
  24     X,Y : horizontal and vertical size of the board
  25     state : dictionary mapping (x,y) to 0 or 1
  26
  27     Methods:
  28     display(update_board) -- If update_board is true, compute the
  29                              next generation.  Then display the state
  30                              of the board and refresh the screen.
  31     erase() -- clear the entire board
  32     makeRandom() -- fill the board randomly
  33     set(y,x) -- set the given cell to Live; doesn't refresh the screen
  34     toggle(y,x) -- change the given cell from live to dead, or vice
  35                    versa, and refresh the screen display
  36
  37     """
  38     def __init__(self, scr, char=ord('*')):
  39         """Create a new LifeBoard instance.
  40
  41         scr -- curses screen object to use for display
  42         char -- character used to render live cells (default: '*')
  43         """
  44         self.state={} ; self.scr=scr
  45         Y, X = self.scr.getmaxyx()
  46         self.X, self.Y = X-2, Y-2-1
  47         self.char = char
  48         self.scr.clear()
  49
  50         # Draw a border around the board
  51         border_line='+'+(self.X*'-')+'+'
  52         self.scr.addstr(0, 0, border_line)
  53         self.scr.addstr(self.Y+1,0, border_line)
  54         for y in range(0, self.Y):
  55             self.scr.addstr(1+y, 0, '|')
  56             self.scr.addstr(1+y, self.X+1, '|')
  57         self.scr.refresh()
  58
  59     def set(self, y, x):
  60         """Set a cell to the live state"""
  61         if x<0 or self.X<=x or y<0 or self.Y<=y:
  62             raise ValueError, "Coordinates out of range %i,%i"% (y,x)
  63         self.state[x,y] = 1
  64
  65     def toggle(self, y, x):
  66         """Toggle a cell's state between live and dead"""
  67         if x<0 or self.X<=x or y<0 or self.Y<=y:
  68             raise ValueError, "Coordinates out of range %i,%i"% (y,x)
  69         if self.state.has_key( (x,y) ):
  70             del self.state[x,y]
  71             self.scr.addch(y+1, x+1, ' ')
  72         else:
  73             self.state[x,y]=1
  74             self.scr.addch(y+1, x+1, self.char)
  75         self.scr.refresh()
  76
  77     def erase(self):
  78         """Clear the entire board and update the board display"""
  79         self.state={}
  80         self.display(update_board=0)
  81
  82     def display(self, update_board=1):
  83         """Display the whole board, optionally computing one generation"""
  84         M,N = self.X, self.Y
  85         if not update_board:
  86             for i in range(0, M):
  87                 for j in range(0, N):
  88                         if self.state.has_key( (i,j) ):
  89                             self.scr.addch(j+1, i+1, self.char)
  90                         else:
  91                             self.scr.addch(j+1, i+1, ' ')
  92             self.scr.refresh()
  93             return
  94
  95         d={} ; self.boring=1
  96         for i in range(0, M):
  97             L=range( max(0, i-1), min(M, i+2) )
  98             for j in range(0, N):
  99                 s=0
 100                 live=self.state.has_key( (i,j) )
 101                 for k in range( max(0, j-1), min(N, j+2) ):
 102                     for l in L:
 103                         if self.state.has_key( (l,k) ):
 104                             s=s+1
 105                 s=s-live
 106                 if s==3:
 107                     # Birth
 108                     d[i,j]=1
 109                     self.scr.addch(j+1, i+1, self.char)
 110                     if not live: self.boring=0
 111                 elif s==2 and live: d[i,j]=1       # Survival
 112                 elif live:
 113                     # Death
 114                     self.scr.addch(j+1, i+1, ' ')
 115                     self.boring=0
 116         self.state=d
 117         self.scr.refresh()
 118
 119     def makeRandom(self):
 120         "Fill the board with a random pattern"
 121         import whrandom
 122         self.state={}
 123         for i in range(0, self.X):
 124             for j in range(0, self.Y):
 125                 if whrandom.random()*10>5.0: self.set(j,i)
 126
 127
 128 def erase_menu(stdscr, menu_y):
 129     "Clear the space where the menu resides"
 130     stdscr.move(menu_y, 0) ; stdscr.clrtoeol()
 131     stdscr.move(menu_y+1, 0) ; stdscr.clrtoeol()
 132
 133 def display_menu(stdscr, menu_y):
 134     "Display the menu of possible keystroke commands"
 135     erase_menu(stdscr, menu_y)
 136     stdscr.addstr(menu_y, 4,
 137                   'Use the cursor keys to move, and space or Enter to toggle a cell.')
 138     stdscr.addstr(menu_y+1, 4,
 139                   'E)rase the board, R)andom fill, S)tep once or C)ontinuously, Q)uit')
 140
 141 def main(stdscr):
 142     import string, curses
 143
 144     # Clear the screen and display the menu of keys
 145     stdscr.clear()
 146     stdscr_y, stdscr_x = stdscr.getmaxyx()
 147     menu_y=(stdscr_y-3)-1
 148     display_menu(stdscr, menu_y)
 149
 150     # Allocate a subwindow for the Life board and create the board object
 151     subwin=stdscr.subwin(stdscr_y-3, stdscr_x, 0, 0)
 152     board=LifeBoard(subwin, char=ord('*'))
 153     board.display(update_board=0)
 154
 155     # xpos, ypos are the cursor's position
 156     xpos, ypos = board.X/2, board.Y/2
 157
 158     # Main loop:
 159     while (1):
 160         stdscr.move(1+ypos, 1+xpos)     # Move the cursor
 161         c=stdscr.getch()                # Get a keystroke
 162         if 0<c<256:
 163             c=chr(c)
 164             if c in ' \n':
 165                 board.toggle(ypos, xpos)
 166             elif c in 'Cc':
 167                 erase_menu(stdscr, menu_y)
 168                 stdscr.addstr(menu_y, 6, ' Hit any key to stop continuously '
 169                               'updating the screen.')
 170                 stdscr.refresh()
 171                 # Activate nodelay mode; getch() will return -1
 172                 # if no keystroke is available, instead of waiting.
 173                 stdscr.nodelay(1)
 174                 while (1):
 175                     c=stdscr.getch()
 176                     if c!=-1: break
 177                     stdscr.addstr(0,0, '/'); stdscr.refresh()
 178                     board.display()
 179                     stdscr.addstr(0,0, '+'); stdscr.refresh()
 180
 181                 stdscr.nodelay(0)       # Disable nodelay mode
 182                 display_menu(stdscr, menu_y)
 183
 184             elif c in 'Ee': board.erase()
 185             elif c in 'Qq': break
 186             elif c in 'Rr':
 187                 board.makeRandom()
 188                 board.display(update_board=0)
 189             elif c in 'Ss':
 190                 board.display()
 191             else: pass                  # Ignore incorrect keys
 192         elif c==curses.KEY_UP and ypos>0:            ypos=ypos-1
 193         elif c==curses.KEY_DOWN and ypos<board.Y-1:  ypos=ypos+1
 194         elif c==curses.KEY_LEFT and xpos>0:          xpos=xpos-1
 195         elif c==curses.KEY_RIGHT and xpos<board.X-1: xpos=xpos+1
 196         else: pass                      # Ignore incorrect keys
 197
 198 if __name__=='__main__':
 199     import curses, traceback
 200     try:
 201         # Initialize curses
 202         stdscr=curses.initscr()
 203         # Turn off echoing of keys, and enter cbreak mode,
 204         # where no buffering is performed on keyboard input
 205         curses.noecho() ; curses.cbreak()
 206
 207         # In keypad mode, escape sequences for special keys
 208         # (like the cursor keys) will be interpreted and
 209         # a special value like curses.KEY_LEFT will be returned
 210         stdscr.keypad(1)
 211         main(stdscr)                    # Enter the main loop
 212         # Set everything back to normal
 213         stdscr.keypad(0)
 214         curses.echo() ; curses.nocbreak()
 215         curses.endwin()                 # Terminate curses
 216     except:
 217         # In the event of an error, restore the terminal
 218         # to a sane state.
 219         stdscr.keypad(0)
 220         curses.echo() ; curses.nocbreak()
 221         curses.endwin()
 222         traceback.print_exc()           # Print the exception
 223