clip_board.py

import Image
from collections import Counter

IMAGE_FILE = 'testris_fb.png'

def get_tetris_vert_bounds_from_img(img):
    '''Returns the left and right crop boundaries of an image of the player's Tetris Battle board.'''
    img_width, img_height = img.size

    left_tri_black_coords = []
    for row_num in xrange(img_height):
        num_black_pixels = 0
        found_black_pixel = False
        for col_num in xrange(img_width):
            if img.getpixel((col_num, row_num)) == (0, 0, 0):
                if not found_black_pixel:
                    found_black_pixel = True
                num_black_pixels += 1
            else:
                if num_black_pixels == 6:
                    start_col = col_num - 6
                    end_col = col_num - 1
                    left_tri_black_coords.append(start_col)
                found_black_pixel = False
                num_black_pixels = 0

    left_tri_black_count = Counter(left_tri_black_coords)
    inner_board_bound_tuples = left_tri_black_count.most_common(6)
    
    inner_board_bounds = []
    for coord, count in inner_board_bound_tuples:
        inner_board_bounds.append(coord)
    inner_board_bounds.sort()
    inner_board_bounds = inner_board_bounds[:2]
    left_bound_no_border = inner_board_bounds[0] + 6
    right_bound_no_border = inner_board_bounds[1] - 1

    return (left_bound_no_border, right_bound_no_border)

def get_tetris_horiz_bounds_from_img(img):
    '''Returns the top and bottom crop boundaries of an image of the player's Tetris Battle board.'''
    img_width, img_height = img.size

    top_tri_black_coords = []
    for col_num in xrange(img_width):
        num_black_pixels = 0
        found_black_pixel = False
        for row_num in xrange(img_height):
            if img.getpixel((col_num, row_num)) == (0, 0, 0):
                if not found_black_pixel:
                    found_black_pixel = True
                num_black_pixels += 1
            else:
                if num_black_pixels == 6:
                    start_row = row_num - 6
                    end_row = row_num - 1
                    top_tri_black_coords.append(start_row)
                found_black_pixel = False
                num_black_pixels = 0

    top_tri_black_count = Counter(top_tri_black_coords)
    inner_board_bound_tuples = top_tri_black_count.most_common(2)

    inner_board_bounds = []
    for coord, count in inner_board_bound_tuples:
        inner_board_bounds.append(coord)
    inner_board_bounds.sort()
    top_bound_no_border = inner_board_bounds[0] + 6
    bottom_bound_no_border = inner_board_bounds[1] - 1
    
    return (top_bound_no_border, bottom_bound_no_border)

tetris_img = Image.open(IMAGE_FILE)

print 'Getting horizontal boundaries...'
vert_bounds = get_tetris_vert_bounds_from_img(tetris_img)
print 'Done! Vertical bounds:', vert_bounds

print 'Getting vertical boundaries...'
horiz_bounds = get_tetris_horiz_bounds_from_img(tetris_img)
print 'Done! Horizontal bounds:', horiz_bounds

left_bound, right_bound = vert_bounds
top_bound, bottom_bound = horiz_bounds
tetris_img_width, tetris_img_height = tetris_img.size
cropped = tetris_img.crop((left_bound, top_bound, right_bound, bottom_bound))
cropped.show()