solitaire.py

reduced python source for embedded apps

#! /usr/bin/env python

"""Solitaire game, much like the one that comes with MS Windows.

Limitations:

- No cute graphical images for the playing cards faces or backs.
- No scoring or timer.
- No undo.
- No option to turn 3 cards at a time.
- No keyboard shortcuts.
- Less fancy animation when you win.
- The determination of which stack you drag to is more relaxed.
  
Apology:

I'm not much of a card player, so my terminology in these comments may
at times be a little unusual.  If you have suggestions, please let me
know!

"""

# Imports

import math
import random

from Tkinter import *
from Canvas import Rectangle, CanvasText, Group, Window


# Fix a bug in Canvas.Group as distributed in Python 1.4.  The
# distributed bind() method is broken.  Rather than asking you to fix
# the source, we fix it here by deriving a subclass:

class Group(Group):
    def bind(self, sequence=None, command=None):
	return self.canvas.tag_bind(self.id, sequence, command)


# Constants determining the size and lay-out of cards and stacks.  We
# work in a "grid" where each card/stack is surrounded by MARGIN
# pixels of space on each side, so adjacent stacks are separated by
# 2*MARGIN pixels.  OFFSET is the offset used for displaying the
# face down cards in the row stacks.

CARDWIDTH = 100
CARDHEIGHT = 150
MARGIN = 10
XSPACING = CARDWIDTH + 2*MARGIN
YSPACING = CARDHEIGHT + 4*MARGIN
OFFSET = 5

# The background color, green to look like a playing table.  The
# standard green is way too bright, and dark green is way to dark, so
# we use something in between.  (There are a few more colors that
# could be customized, but they are less controversial.)

BACKGROUND = '#070'


# Suits and colors.  The values of the symbolic suit names are the
# strings used to display them (you change these and VALNAMES to
# internationalize the game).  The COLOR dictionary maps suit names to
# colors (red and black) which must be Tk color names.  The keys() of
# the COLOR dictionary conveniently provides us with a list of all
# suits (in arbitrary order).

HEARTS = 'Heart'
DIAMONDS = 'Diamond'
CLUBS = 'Club'
SPADES = 'Spade'

RED = 'red'
BLACK = 'black'

COLOR = {}
for s in (HEARTS, DIAMONDS):
    COLOR[s] = RED
for s in (CLUBS, SPADES):
    COLOR[s] = BLACK

ALLSUITS = COLOR.keys()
NSUITS = len(ALLSUITS)


# Card values are 1-13.  We also define symbolic names for the picture
# cards.  ALLVALUES is a list of all card values.

ACE = 1
JACK = 11
QUEEN = 12
KING = 13
ALLVALUES = range(1, 14) # (one more than the highest value)
NVALUES = len(ALLVALUES)


# VALNAMES is a list that maps a card value to string.  It contains a
# dummy element at index 0 so it can be indexed directly with the card
# value.

VALNAMES = ["", "A"] + map(str, range(2, 11)) + ["J", "Q", "K"]


# Solitaire constants.  The only one I can think of is the number of
# row stacks.

NROWS = 7


# The rest of the program consists of class definitions.  These are
# further described in their documentation strings.


class Card:

    """A playing card.

    A card doesn't record to which stack it belongs; only the stack
    records this (it turns out that we always know this from the
    context, and this saves a ``double update'' with potential for
    inconsistencies).

    Public methods:

    moveto(x, y) -- move the card to an absolute position
    moveby(dx, dy) -- move the card by a relative offset
    tkraise() -- raise the card to the top of its stack
    showface(), showback() -- turn the card face up or down & raise it

    Public read-only instance variables:

    suit, value, color -- the card's suit, value and color
    face_shown -- true when the card is shown face up, else false

    Semi-public read-only instance variables (XXX should be made
    private):
    
    group -- the Canvas.Group representing the card
    x, y -- the position of the card's top left corner

    Private instance variables:

    __back, __rect, __text -- the canvas items making up the card

    (To show the card face up, the text item is placed in front of
    rect and the back is placed behind it.  To show it face down, this
    is reversed.  The card is created face down.)

    """

    def __init__(self, suit, value, canvas):
	"""Card constructor.

	Arguments are the card's suit and value, and the canvas widget.

	The card is created at position (0, 0), with its face down
	(adding it to a stack will position it according to that
	stack's rules).

	"""
	self.suit = suit
	self.value = value
	self.color = COLOR[suit]
	self.face_shown = 0

	self.x = self.y = 0
	self.group = Group(canvas)

	text = "%s  %s" % (VALNAMES[value], suit)
	self.__text = CanvasText(canvas, CARDWIDTH/2, 0,
			       anchor=N, fill=self.color, text=text)
	self.group.addtag_withtag(self.__text)

	self.__rect = Rectangle(canvas, 0, 0, CARDWIDTH, CARDHEIGHT,
			      outline='black', fill='white')
	self.group.addtag_withtag(self.__rect)

	self.__back = Rectangle(canvas, MARGIN, MARGIN,
			      CARDWIDTH-MARGIN, CARDHEIGHT-MARGIN,
			      outline='black', fill='blue')
	self.group.addtag_withtag(self.__back)

    def __repr__(self):
	"""Return a string for debug print statements."""
	return "Card(%s, %s)" % (`self.suit`, `self.value`)

    def moveto(self, x, y):
	"""Move the card to absolute position (x, y)."""
	self.moveby(x - self.x, y - self.y)

    def moveby(self, dx, dy):
	"""Move the card by (dx, dy)."""
	self.x = self.x + dx
	self.y = self.y + dy
	self.group.move(dx, dy)

    def tkraise(self):
	"""Raise the card above all other objects in its canvas."""
	self.group.tkraise()

    def showface(self):
	"""Turn the card's face up."""
	self.tkraise()
	self.__rect.tkraise()
	self.__text.tkraise()
	self.face_shown = 1

    def showback(self):
	"""Turn the card's face down."""
	self.tkraise()
	self.__rect.tkraise()
	self.__back.tkraise()
	self.face_shown = 0


class Stack:

    """A generic stack of cards.

    This is used as a base class for all other stacks (e.g. the deck,
    the suit stacks, and the row stacks).

    Public methods:

    add(card) -- add a card to the stack
    delete(card) -- delete a card from the stack
    showtop() -- show the top card (if any) face up
    deal() -- delete and return the top card, or None if empty

    Method that subclasses may override:

    position(card) -- move the card to its proper (x, y) position

        The default position() method places all cards at the stack's
        own (x, y) position.

    userclickhandler(), userdoubleclickhandler() -- called to do
    subclass specific things on single and double clicks

        The default user (single) click handler shows the top card
        face up.  The default user double click handler calls the user
	single click handler.

    usermovehandler(cards) -- called to complete a subpile move

        The default user move handler moves all moved cards back to
        their original position (by calling the position() method).

    Private methods:

    clickhandler(event), doubleclickhandler(event),
    motionhandler(event), releasehandler(event) -- event handlers

        The default event handlers turn the top card of the stack with
        its face up on a (single or double) click, and also support
        moving a subpile around.
    
    startmoving(event) -- begin a move operation
    finishmoving() -- finish a move operation

    """

    def __init__(self, x, y, game=None):
	"""Stack constructor.

	Arguments are the stack's nominal x and y position (the top
	left corner of the first card placed in the stack), and the
	game object (which is used to get the canvas; subclasses use
	the game object to find other stacks).

	"""
	self.x = x
	self.y = y
	self.game = game
	self.cards = []
	self.group = Group(self.game.canvas)
	self.group.bind('<1>', self.clickhandler)
 	self.group.bind('<Double-1>', self.doubleclickhandler)
	self.group.bind('<B1-Motion>', self.motionhandler)
	self.group.bind('<ButtonRelease-1>', self.releasehandler)
	self.makebottom()

    def makebottom(self):
	pass

    def __repr__(self):
	"""Return a string for debug print statements."""
	return "%s(%d, %d)" % (self.__class__.__name__, self.x, self.y)

    # Public methods

    def add(self, card):
	self.cards.append(card)
	card.tkraise()
	self.position(card)
	self.group.addtag_withtag(card.group)

    def delete(self, card):
	self.cards.remove(card)
	card.group.dtag(self.group)

    def showtop(self):
	if self.cards:
	    self.cards[-1].showface()

    def deal(self):
	if not self.cards:
	    return None
	card = self.cards[-1]
	self.delete(card)
	return card

    # Subclass overridable methods

    def position(self, card):
	card.moveto(self.x, self.y)

    def userclickhandler(self):