# Array-Backed GridΒΆ

"""
Array Backed Grid

Show how to use a two-dimensional list/array to back the display of a
grid on-screen.
"""

# Set how many rows and columns we will have
ROW_COUNT = 10
COLUMN_COUNT = 10

# This sets the WIDTH and HEIGHT of each grid location
WIDTH = 20
HEIGHT = 20

# This sets the margin between each cell
# and on the edges of the screen.
MARGIN = 5

# Do the math to figure out oiur screen dimensions
SCREEN_WIDTH = (WIDTH + MARGIN) * COLUMN_COUNT + MARGIN
SCREEN_HEIGHT = (HEIGHT + MARGIN) * ROW_COUNT + MARGIN

"""
Main application class.
"""

def __init__(self, width, height):
"""
Set up the application.
"""
super().__init__(width, height)
# Create a 2 dimensional array. A two dimensional
# array is simply a list of lists.
self.grid = []
for row in range(ROW_COUNT):
# Add an empty array that will hold each cell
# in this row
self.grid.append([])
for column in range(COLUMN_COUNT):
self.grid[row].append(0)  # Append a cell

def on_draw(self):
"""
Render the screen.
"""

# This command has to happen before we start drawing

# Draw the grid
for row in range(ROW_COUNT):
for column in range(COLUMN_COUNT):
# Figure out what color to draw the box
if self.grid[row][column] == 1:
else:

# Do the math to figure out where the box is
x = (MARGIN + WIDTH) * column + MARGIN + WIDTH // 2
y = (MARGIN + HEIGHT) * row + MARGIN + HEIGHT // 2

# Draw the box

def on_mouse_press(self, x, y, button, modifiers):
"""
Called when the user presses a mouse button.
"""

# Change the x/y screen coordinates to grid coordinates
column = x // (WIDTH + MARGIN)
row = y // (HEIGHT + MARGIN)

print("Click coordinates: ({}, {}). Grid coordinates: ({}, {})"
.format(x, y, row, column))

# Make sure we are on-grid. It is possible to click in the upper right
# corner in the margin and go to a grid location that doesn't exist
if row < ROW_COUNT and column < COLUMN_COUNT:

# Flip the location between 1 and 0.
if self.grid[row][column] == 0:
self.grid[row][column] = 1
else:
self.grid[row][column] = 0

window = MyApplication(SCREEN_WIDTH, SCREEN_HEIGHT)