def test_gridify_generates_correct_sequence_of_borders(self):
# get the test image which is constructed as follows:
grid_image_path = path.join(this_path,
'grid (tlbr padding - 1, 2, 3, 4).png')
grid_image = cv2.imread(grid_image_path)
self.assertIsNotNone(grid_image) # just confirm file loaded
# 4 rows, 2 columns
dimensions = (4, 2)
# (top, left, bottom, right) padding:
# = (1px, 2px, 3px, 4px)
# = (1/5, 2/10, 3/5, 4/10)
# = (0.2, 0.2, 0.6, 0.4)
cell_padding = 0.2, 0.2, 0.6, 0.4
# ==> remaining cell image shape is 1 row, 4 columns (3 channels)
channels = 3
cell_shape_spec = (1, 4, channels) # 1 row, 4 columns, 3 channels
# ==> content of each cell image should be exactly the colored parts
# in the image as follows:
red = (0, 0, 255)
green = (0, 255, 0)
blue = (255, 0, 0)
white = (255, 255, 255)
colors_spec = [[red, white],
[green, red],
[blue, green],
[white, blue]]
colors_spec = numpy.asarray(colors_spec)
# gridify the image and confirm all sub images match the above specs
grid = Grid(dimensions, cell_padding)
for grid_position, borders in grid.borders_by_grid_position(grid_image):
top, left, bottom, right = borders
# confirm the size
cell_shape = (bottom - top, right - left, channels)
self.assertEqual(cell_shape, cell_shape_spec)
spec_pixel = colors_spec[grid_position]
# confirm the color for each pixel in the cell
for pixel_row in range(top, bottom):
for pixel_col in range(left, right):
p = pixel_row, pixel_col
image_pixel = grid_image[p]
self.assertTrue(numpy.all(image_pixel == spec_pixel),
'Pixel in grid cell:'
'\n{}: {}'
'\nunexpectedly not equal to specification:'
'\n{}'.format(grid_position, image_pixel,
spec_pixel))