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1#!/usr/bin/env python3
2
3"""
4A curses-based version of Conway's Game of Life.
5
6An empty board will be displayed, and the following commands are available:
7 E : Erase the board
8 R : Fill the board randomly
9 S : Step for a single generation
10 C : Update continuously until a key is struck
11 Q : Quit
12 Cursor keys :  Move the cursor around the board
13 Space or Enter : Toggle the contents of the cursor's position
14
15Contributed by Andrew Kuchling, Mouse support and color by Dafydd Crosby.
16"""
17
18import curses
19import random
20
21
22class LifeBoard:
23    """Encapsulates a Life board
24
25    Attributes:
26    X,Y : horizontal and vertical size of the board
27    state : dictionary mapping (x,y) to 0 or 1
28
29    Methods:
30    display(update_board) -- If update_board is true, compute the
31                             next generation.  Then display the state
32                             of the board and refresh the screen.
33    erase() -- clear the entire board
34    make_random() -- fill the board randomly
35    set(y,x) -- set the given cell to Live; doesn't refresh the screen
36    toggle(y,x) -- change the given cell from live to dead, or vice
37                   versa, and refresh the screen display
38
39    """
40    def __init__(self, scr, char=ord('*')):
41        """Create a new LifeBoard instance.
42
43        scr -- curses screen object to use for display
44        char -- character used to render live cells (default: '*')
45        """
46        self.state = {}
47        self.scr = scr
48        Y, X = self.scr.getmaxyx()
49        self.X, self.Y = X - 2, Y - 2 - 1
50        self.char = char
51        self.scr.clear()
52
53        # Draw a border around the board
54        border_line = '+' + (self.X * '-') + '+'
55        self.scr.addstr(0, 0, border_line)
56        self.scr.addstr(self.Y + 1, 0, border_line)
57        for y in range(0, self.Y):
58            self.scr.addstr(1 + y, 0, '|')
59            self.scr.addstr(1 + y, self.X + 1, '|')
60        self.scr.refresh()
61
62    def set(self, y, x):
63        """Set a cell to the live state"""
64        if x < 0 or self.X <= x or y < 0 or self.Y <= y:
65            raise ValueError("Coordinates out of range %i,%i" % (y, x))
66        self.state[x, y] = 1
67
68    def toggle(self, y, x):
69        """Toggle a cell's state between live and dead"""
70        if x < 0 or self.X <= x or y < 0 or self.Y <= y:
71            raise ValueError("Coordinates out of range %i,%i" % (y, x))
72        if (x, y) in self.state:
73            del self.state[x, y]
74            self.scr.addch(y + 1, x + 1, ' ')
75        else:
76            self.state[x, y] = 1
77            if curses.has_colors():
78                # Let's pick a random color!
79                self.scr.attrset(curses.color_pair(random.randrange(1, 7)))
80            self.scr.addch(y + 1, x + 1, self.char)
81            self.scr.attrset(0)
82        self.scr.refresh()
83
84    def erase(self):
85        """Clear the entire board and update the board display"""
86        self.state = {}
87        self.display(update_board=False)
88
89    def display(self, update_board=True):
90        """Display the whole board, optionally computing one generation"""
91        M, N = self.X, self.Y
92        if not update_board:
93            for i in range(0, M):
94                for j in range(0, N):
95                    if (i, j) in self.state:
96                        self.scr.addch(j + 1, i + 1, self.char)
97                    else:
98                        self.scr.addch(j + 1, i + 1, ' ')
99            self.scr.refresh()
100            return
101
102        d = {}
103        self.boring = 1
104        for i in range(0, M):
105            L = range(max(0, i - 1), min(M, i + 2))
106            for j in range(0, N):
107                s = 0
108                live = (i, j) in self.state
109                for k in range(max(0, j - 1), min(N, j + 2)):
110                    for l in L:
111                        if (l, k) in self.state:
112                            s += 1
113                s -= live
114                if s == 3:
115                    # Birth
116                    d[i, j] = 1
117                    if curses.has_colors():
118                        # Let's pick a random color!
119                        self.scr.attrset(curses.color_pair(
120                            random.randrange(1, 7)))
121                    self.scr.addch(j + 1, i + 1, self.char)
122                    self.scr.attrset(0)
123                    if not live:
124                        self.boring = 0
125                elif s == 2 and live:
126                    # Survival
127                    d[i, j] = 1
128                elif live:
129                    # Death
130                    self.scr.addch(j + 1, i + 1, ' ')
131                    self.boring = 0
132        self.state = d
133        self.scr.refresh()
134
135    def make_random(self):
136        "Fill the board with a random pattern"
137        self.state = {}
138        for i in range(0, self.X):
139            for j in range(0, self.Y):
140                if random.random() > 0.5:
141                    self.set(j, i)
142
143
144def erase_menu(stdscr, menu_y):
145    "Clear the space where the menu resides"
146    stdscr.move(menu_y, 0)
147    stdscr.clrtoeol()
148    stdscr.move(menu_y + 1, 0)
149    stdscr.clrtoeol()
150
151
152def display_menu(stdscr, menu_y):
153    "Display the menu of possible keystroke commands"
154    erase_menu(stdscr, menu_y)
155
156    # If color, then light the menu up :-)
157    if curses.has_colors():
158        stdscr.attrset(curses.color_pair(1))
159    stdscr.addstr(menu_y, 4,
160        'Use the cursor keys to move, and space or Enter to toggle a cell.')
161    stdscr.addstr(menu_y + 1, 4,
162        'E)rase the board, R)andom fill, S)tep once or C)ontinuously, Q)uit')
163    stdscr.attrset(0)
164
165
166def keyloop(stdscr):
167    # Clear the screen and display the menu of keys
168    stdscr.clear()
169    stdscr_y, stdscr_x = stdscr.getmaxyx()
170    menu_y = (stdscr_y - 3) - 1
171    display_menu(stdscr, menu_y)
172
173    # If color, then initialize the color pairs
174    if curses.has_colors():
175        curses.init_pair(1, curses.COLOR_BLUE, 0)
176        curses.init_pair(2, curses.COLOR_CYAN, 0)
177        curses.init_pair(3, curses.COLOR_GREEN, 0)
178        curses.init_pair(4, curses.COLOR_MAGENTA, 0)
179        curses.init_pair(5, curses.COLOR_RED, 0)
180        curses.init_pair(6, curses.COLOR_YELLOW, 0)
181        curses.init_pair(7, curses.COLOR_WHITE, 0)
182
183    # Set up the mask to listen for mouse events
184    curses.mousemask(curses.BUTTON1_CLICKED)
185
186    # Allocate a subwindow for the Life board and create the board object
187    subwin = stdscr.subwin(stdscr_y - 3, stdscr_x, 0, 0)
188    board = LifeBoard(subwin, char=ord('*'))
189    board.display(update_board=False)
190
191    # xpos, ypos are the cursor's position
192    xpos, ypos = board.X // 2, board.Y // 2
193
194    # Main loop:
195    while True:
196        stdscr.move(1 + ypos, 1 + xpos)   # Move the cursor
197        c = stdscr.getch()                # Get a keystroke
198        if 0 < c < 256:
199            c = chr(c)
200            if c in ' \n':
201                board.toggle(ypos, xpos)
202            elif c in 'Cc':
203                erase_menu(stdscr, menu_y)
204                stdscr.addstr(menu_y, 6, ' Hit any key to stop continuously '
205                              'updating the screen.')
206                stdscr.refresh()
207                # Activate nodelay mode; getch() will return -1
208                # if no keystroke is available, instead of waiting.
209                stdscr.nodelay(1)
210                while True:
211                    c = stdscr.getch()
212                    if c != -1:
213                        break
214                    stdscr.addstr(0, 0, '/')
215                    stdscr.refresh()
216                    board.display()
217                    stdscr.addstr(0, 0, '+')
218                    stdscr.refresh()
219
220                stdscr.nodelay(0)       # Disable nodelay mode
221                display_menu(stdscr, menu_y)
222
223            elif c in 'Ee':
224                board.erase()
225            elif c in 'Qq':
226                break
227            elif c in 'Rr':
228                board.make_random()
229                board.display(update_board=False)
230            elif c in 'Ss':
231                board.display()
232            else:
233                # Ignore incorrect keys
234                pass
235        elif c == curses.KEY_UP and ypos > 0:
236            ypos -= 1
237        elif c == curses.KEY_DOWN and ypos + 1 < board.Y:
238            ypos += 1
239        elif c == curses.KEY_LEFT and xpos > 0:
240            xpos -= 1
241        elif c == curses.KEY_RIGHT and xpos + 1 < board.X:
242            xpos += 1
243        elif c == curses.KEY_MOUSE:
244            mouse_id, mouse_x, mouse_y, mouse_z, button_state = curses.getmouse()
245            if (mouse_x > 0 and mouse_x < board.X + 1 and
246                mouse_y > 0 and mouse_y < board.Y + 1):
247                xpos = mouse_x - 1
248                ypos = mouse_y - 1
249                board.toggle(ypos, xpos)
250            else:
251                # They've clicked outside the board
252                curses.flash()
253        else:
254            # Ignore incorrect keys
255            pass
256
257
258def main(stdscr):
259    keyloop(stdscr)                 # Enter the main loop
260
261if __name__ == '__main__':
262    curses.wrapper(main)
263