Welcome folks today in this blog post we will be building a tetris game in tkinter using python. All the full source code of the application is shown below.
Get Started
In order to get started you need to make an app.py file and copy paste the following code
app.py
import tkinter as Tkinter
from tkinter import Canvas, Label, Tk, StringVar
from tkinter import messagebox
from random import choice
from collections import Counter
class Game():
WIDTH = 300
HEIGHT = 500
def start(self):
'''Starts the game.
Creates a window, a canvas, and a first shape. Binds the event handler.
Then starts a GUI timer of ms interval self.speed and starts the GUI main
loop.
'''
#TODO start() needs to be refactored so that the creation of the
# window, label, and canvas are independent from setting them to
# defaults and starting the game.
#
# There should also be a way for the user to restart and pause
# the game if he or she wishes.
#
# It's a little weird that level is based only on time and that
# as a result it increases faster and faster. Wouldn't it make
# more sense for level to be a result of completed lines?
self.level = 1
self.score = 0
self.speed = 500
self.counter = 0
self.create_new_game = True
self.root = Tk()
self.root.title("Tetris")
self.status_var = StringVar()
self.status_var.set("Level: 1, Score: 0")
self.status = Label(self.root,
textvariable=self.status_var,
font=("Helvetica", 10, "bold"))
self.status.pack()
self.canvas = Canvas(
self.root,
width=Game.WIDTH,
height=Game.HEIGHT)
self.canvas.pack()
self.root.bind("<Key>", self.handle_events)
self.timer()
self.root.mainloop()
def timer(self):
'''Every self.speed ms, attempt to cause the current_shape to fall().
If fall() returns False, create a new shape and check if it can fall.
If it can't, then the game is over.
'''
if self.create_new_game == True:
self.current_shape = Shape(self.canvas)
self.create_new_game = False
if not self.current_shape.fall():
lines = self.remove_complete_lines()
if lines:
self.score += 10 * self.level**2 * lines**2
self.status_var.set("Level: %d, Score: %d" %
(self.level, self.score))
self.current_shape = Shape(self.canvas)
if self.is_game_over():
#TODO This is a problem. You rely on the timer method to
# create a new game rather than creating it here. As a
# result, there is an intermittent error where the user
# event keypress Down eventually causes can_move_box
# to throw an IndexError, since the current shape has
# no boxes. Instead, you need to cleanly start a new
# game. I think refactoring start() might help a lot
# here.
#
# Furthermore, starting a new game currently doesn't reset
# the levels. You should place all your starting constants
# in the same place so it's clear what needs to be reset
# when.
self.create_new_game = True
self.game_over()
self.counter += 1
if self.counter == 5:
self.level += 1
self.speed -= 20
self.counter = 0
self.status_var.set("Level: %d, Score: %d" %
(self.level, self.score))
self.root.after(self.speed, self.timer)
def handle_events(self, event):
'''Handle all user events.'''
if event.keysym == "Left": self.current_shape.move(-1, 0)
if event.keysym == "Right": self.current_shape.move(1, 0)
if event.keysym == "Down": self.current_shape.move(0, 1)
if event.keysym == "Up": self.current_shape.rotate()
def is_game_over(self):
'''Check if a newly created shape is able to fall.
If it can't fall, then the game is over.
'''
for box in self.current_shape.boxes:
if not self.current_shape.can_move_box(box, 0, 1):
return True
return False
def remove_complete_lines(self):
shape_boxes_coords = [self.canvas.coords(box)[3] for box
in self.current_shape.boxes]
all_boxes = self.canvas.find_all()
all_boxes_coords = {k : v for k, v in
zip(all_boxes, [self.canvas.coords(box)[3]
for box in all_boxes])}
lines_to_check = set(shape_boxes_coords)
boxes_to_check = dict((k, v) for k, v in all_boxes_coords.iteritems()
if any(v == line for line in lines_to_check))
counter = Counter()
for box in boxes_to_check.values(): counter[box] += 1
complete_lines = [k for k, v in counter.iteritems()
if v == (Game.WIDTH/Shape.BOX_SIZE)]
if not complete_lines: return False
for k, v in boxes_to_check.iteritems():
if v in complete_lines:
self.canvas.delete(k)
del all_boxes_coords[k]
#TODO Would be cooler if the line flashed or something
for (box, coords) in all_boxes_coords.iteritems():
for line in complete_lines:
if coords < line:
self.canvas.move(box, 0, Shape.BOX_SIZE)
return len(complete_lines)
def game_over(self):
self.canvas.delete(Tkinter.ALL)
tkMessageBox.showinfo(
"Game Over",
"You scored %d points." % self.score)
class Shape:
'''Defines a tetris shape.'''
BOX_SIZE = 20
# START_POINT relies on screwy integer arithmetic to approximate the middle
# of the canvas while remaining correctly on the grid.
START_POINT = Game.WIDTH / 2 / BOX_SIZE * BOX_SIZE - BOX_SIZE
SHAPES = (
("yellow", (0, 0), (1, 0), (0, 1), (1, 1)), # square
("lightblue", (0, 0), (1, 0), (2, 0), (3, 0)), # line
("orange", (2, 0), (0, 1), (1, 1), (2, 1)), # right el
("blue", (0, 0), (0, 1), (1, 1), (2, 1)), # left el
("green", (0, 1), (1, 1), (1, 0), (2, 0)), # right wedge
("red", (0, 0), (1, 0), (1, 1), (2, 1)), # left wedge
("purple", (1, 0), (0, 1), (1, 1), (2, 1)), # symmetrical wedge
)
def __init__(self, canvas):
'''Create a shape.
Select a random shape from the SHAPES tuple. Then, for each point
in the shape definition given in the SHAPES tuple, create a
rectangle of size BOX_SIZE. Save the integer references to these
rectangles in the self.boxes list.
Args:
canvas - the parent canvas on which the shape appears
'''
self.boxes = [] # the squares drawn by canvas.create_rectangle()
self.shape = choice(Shape.SHAPES) # a random shape
self.color = self.shape[0]
self.canvas = canvas
for point in self.shape[1:]:
box = canvas.create_rectangle(
point[0] * Shape.BOX_SIZE + Shape.START_POINT,
point[1] * Shape.BOX_SIZE,
point[0] * Shape.BOX_SIZE + Shape.BOX_SIZE + Shape.START_POINT,
point[1] * Shape.BOX_SIZE + Shape.BOX_SIZE,
fill=self.color)
self.boxes.append(box)
def move(self, x, y):
'''Moves this shape (x, y) boxes.'''
if not self.can_move_shape(x, y):
return False
else:
for box in self.boxes:
self.canvas.move(box, x * Shape.BOX_SIZE, y * Shape.BOX_SIZE)
return True
def fall(self):
'''Moves this shape one box-length down.'''
if not self.can_move_shape(0, 1):
return False
else:
for box in self.boxes:
self.canvas.move(box, 0 * Shape.BOX_SIZE, 1 * Shape.BOX_SIZE)
return True
def rotate(self):
'''Rotates the shape clockwise.'''
boxes = self.boxes[:]
pivot = boxes.pop(2)
def get_move_coords(box):
'''Return (x, y) boxes needed to rotate a box around the pivot.'''
box_coords = self.canvas.coords(box)
pivot_coords = self.canvas.coords(pivot)
x_diff = box_coords[0] - pivot_coords[0]
y_diff = box_coords[1] - pivot_coords[1]
x_move = (- x_diff - y_diff) / self.BOX_SIZE
y_move = (x_diff - y_diff) / self.BOX_SIZE
return x_move, y_move
# Check if shape can legally move
for box in boxes:
x_move, y_move = get_move_coords(box)
if not self.can_move_box(box, x_move, y_move):
return False
# Move shape
for box in boxes:
x_move, y_move = get_move_coords(box)
self.canvas.move(box,
x_move * self.BOX_SIZE,
y_move * self.BOX_SIZE)
return True
def can_move_box(self, box, x, y):
'''Check if box can move (x, y) boxes.'''
x = x * Shape.BOX_SIZE
y = y * Shape.BOX_SIZE
coords = self.canvas.coords(box)
# Returns False if moving the box would overrun the screen
if coords[3] + y > Game.HEIGHT: return False
if coords[0] + x < 0: return False
if coords[2] + x > Game.WIDTH: return False
# Returns False if moving box (x, y) would overlap another box
overlap = set(self.canvas.find_overlapping(
(coords[0] + coords[2]) / 2 + x,
(coords[1] + coords[3]) / 2 + y,
(coords[0] + coords[2]) / 2 + x,
(coords[1] + coords[3]) / 2 + y
))
other_items = set(self.canvas.find_all()) - set(self.boxes)
if overlap & other_items: return False
return True
def can_move_shape(self, x, y):
'''Check if the shape can move (x, y) boxes.'''
for box in self.boxes:
if not self.can_move_box(box, x, y): return False
return True
if __name__ == "__main__":
game = Game()
game.start()
And now if you execute the python script by typing the below command
python app.py
