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#!/usr/bin/env python
# life.py -- A curses-based version of Conway's Game of Life.
# Contributed by AMK
#
# An empty board will be displayed, and the following commands are available:
# E : Erase the board
# R : Fill the board randomly
# S : Step for a single generation
# C : Update continuously until a key is struck
# Q : Quit
# Cursor keys : Move the cursor around the board
# Space or Enter : Toggle the contents of the cursor's position
#
# TODO :
# Support the mouse
# Use colour if available
# Make board updates faster
#
import random, string, traceback
import curses
class LifeBoard:
"""Encapsulates a Life board
Attributes:
X,Y : horizontal and vertical size of the board
state : dictionary mapping (x,y) to 0 or 1
Methods:
display(update_board) -- If update_board is true, compute the
next generation. Then display the state
of the board and refresh the screen.
erase() -- clear the entire board
makeRandom() -- fill the board randomly
set(y,x) -- set the given cell to Live; doesn't refresh the screen
toggle(y,x) -- change the given cell from live to dead, or vice
versa, and refresh the screen display
"""
def __init__(self, scr, char=ord('*')):
"""Create a new LifeBoard instance.
scr -- curses screen object to use for display
char -- character used to render live cells (default: '*')
"""
self.state={} ; self.scr=scr
Y, X = self.scr.getmaxyx()
self.X, self.Y = X-2, Y-2-1
self.char = char
self.scr.clear()
# Draw a border around the board
border_line='+'+(self.X*'-')+'+'
self.scr.addstr(0, 0, border_line)
self.scr.addstr(self.Y+1,0, border_line)
for y in range(0, self.Y):
self.scr.addstr(1+y, 0, '|')
self.scr.addstr(1+y, self.X+1, '|')
self.scr.refresh()
def set(self, y, x):
"""Set a cell to the live state"""
if x<0 or self.X<=x or y<0 or self.Y<=y:
raise ValueError, "Coordinates out of range %i,%i"% (y,x)
self.state[x,y] = 1
def toggle(self, y, x):
"""Toggle a cell's state between live and dead"""
if x<0 or self.X<=x or y<0 or self.Y<=y:
raise ValueError, "Coordinates out of range %i,%i"% (y,x)
if self.state.has_key( (x,y) ):
del self.state[x,y]
self.scr.addch(y+1, x+1, ' ')
else:
self.state[x,y]=1
self.scr.addch(y+1, x+1, self.char)
self.scr.refresh()
def erase(self):
"""Clear the entire board and update the board display"""
self.state={}
self.display(update_board=0)
def display(self, update_board=1):
"""Display the whole board, optionally computing one generation"""
M,N = self.X, self.Y
if not update_board:
for i in range(0, M):
for j in range(0, N):
if self.state.has_key( (i,j) ):
self.scr.addch(j+1, i+1, self.char)
else:
self.scr.addch(j+1, i+1, ' ')
self.scr.refresh()
return
d={} ; self.boring=1
for i in range(0, M):
L=range( max(0, i-1), min(M, i+2) )
for j in range(0, N):
s=0
live=self.state.has_key( (i,j) )
for k in range( max(0, j-1), min(N, j+2) ):
for l in L:
if self.state.has_key( (l,k) ):
s=s+1
s=s-live
if s==3:
# Birth
d[i,j]=1
self.scr.addch(j+1, i+1, self.char)
if not live: self.boring=0
elif s==2 and live: d[i,j]=1 # Survival
elif live:
# Death
self.scr.addch(j+1, i+1, ' ')
self.boring=0
self.state=d
self.scr.refresh()
def makeRandom(self):
"Fill the board with a random pattern"
self.state={}
for i in range(0, self.X):
for j in range(0, self.Y):
if random.random() > 0.5: self.set(j,i)
def erase_menu(stdscr, menu_y):
"Clear the space where the menu resides"
stdscr.move(menu_y, 0) ; stdscr.clrtoeol()
stdscr.move(menu_y+1, 0) ; stdscr.clrtoeol()
def display_menu(stdscr, menu_y):
"Display the menu of possible keystroke commands"
erase_menu(stdscr, menu_y)
stdscr.addstr(menu_y, 4,
'Use the cursor keys to move, and space or Enter to toggle a cell.')
stdscr.addstr(menu_y+1, 4,
'E)rase the board, R)andom fill, S)tep once or C)ontinuously, Q)uit')
def main(stdscr):
# Clear the screen and display the menu of keys
stdscr.clear()
stdscr_y, stdscr_x = stdscr.getmaxyx()
menu_y=(stdscr_y-3)-1
display_menu(stdscr, menu_y)
# Allocate a subwindow for the Life board and create the board object
subwin=stdscr.subwin(stdscr_y-3, stdscr_x, 0, 0)
board=LifeBoard(subwin, char=ord('*'))
board.display(update_board=0)
# xpos, ypos are the cursor's position
xpos, ypos = board.X/2, board.Y/2
# Main loop:
while (1):
stdscr.move(1+ypos, 1+xpos) # Move the cursor
c=stdscr.getch() # Get a keystroke
if 0<c<256:
c=chr(c)
if c in ' \n':
board.toggle(ypos, xpos)
elif c in 'Cc':
erase_menu(stdscr, menu_y)
stdscr.addstr(menu_y, 6, ' Hit any key to stop continuously '
'updating the screen.')
stdscr.refresh()
# Activate nodelay mode; getch() will return -1
# if no keystroke is available, instead of waiting.
stdscr.nodelay(1)
while (1):
c=stdscr.getch()
if c!=-1: break
stdscr.addstr(0,0, '/'); stdscr.refresh()
board.display()
stdscr.addstr(0,0, '+'); stdscr.refresh()
stdscr.nodelay(0) # Disable nodelay mode
display_menu(stdscr, menu_y)
elif c in 'Ee': board.erase()
elif c in 'Qq': break
elif c in 'Rr':
board.makeRandom()
board.display(update_board=0)
elif c in 'Ss':
board.display()
else: pass # Ignore incorrect keys
elif c==curses.KEY_UP and ypos>0: ypos=ypos-1
elif c==curses.KEY_DOWN and ypos<board.Y-1: ypos=ypos+1
elif c==curses.KEY_LEFT and xpos>0: xpos=xpos-1
elif c==curses.KEY_RIGHT and xpos<board.X-1: xpos=xpos+1
else: pass # Ignore incorrect keys
if __name__=='__main__':
try:
# Initialize curses
stdscr=curses.initscr()
# Turn off echoing of keys, and enter cbreak mode,
# where no buffering is performed on keyboard input
curses.noecho() ; curses.cbreak()
# In keypad mode, escape sequences for special keys
# (like the cursor keys) will be interpreted and
# a special value like curses.KEY_LEFT will be returned
stdscr.keypad(1)
main(stdscr) # Enter the main loop
# Set everything back to normal
stdscr.keypad(0)
curses.echo() ; curses.nocbreak()
curses.endwin() # Terminate curses
except:
# In the event of an error, restore the terminal
# to a sane state.
stdscr.keypad(0)
curses.echo() ; curses.nocbreak()
curses.endwin()
traceback.print_exc() # Print the exception
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