def test_decrease_brightness():
'''Test the function decrase_brightness in img_manip.'''
new_pic = create_pic(4, 4)
new_pic_decrease_bright = img_manip.decrease_brightness(new_pic)
#The average brightness of new_pic_increased_brightness will likely not be
#exactly 10 less than that of new_pic because some RGB values may already be
#0 and cannot decrease, so the function tests for a difference of 10 with
#an error of 2 rather than for strict difference of 10.
old_avg_brightness = avg_bright.average_brightness(new_pic)
new_avg_brightness = avg_bright.average_brightness(new_pic_decrease_bright)
assert old_avg_brightness - new_avg_brightness- 10 < 2, \
"decrease_brightness failed to decrease the picture's average \
def test_white_pic():
"""Test if average_brightness calculates the correct value for a 5x5 picture
consisting of only white pixels."""
new_pic = media.create_picture(5, 5, media.white)
assert (
average_brightness.average_brightness(new_pic) == 255
), "The expected average brightness for a white picture was not obtained."
def test_3_white_pixels_1_black_pixel():
"""Test if average_brightness calculates the correct value for a 2x2 picture
consisting of 3 white pixels and 1 black pixel."""
new_pic = media.create_picture(2, 2, media.white)
media.set_color(media.get_pixel(new_pic, 0, 0), media.black)
assert (
average_brightness.average_brightness(new_pic) == 255 * 3 / 4.0
), "The expected average brightness for a picture with 3 white pixels \
def normalize_brightness (pic):
'''Create a copy of the picture pic, multiply the RGB value of each pixel in
the copy so that the average brightness is 128, and return the copy.'''
new_pic = pic.copy()
orig_avg_brightness = average_brightness.average_brightness (new_pic)
factor = orig_avg_brightness / 128
for pix in new_pic:
pix.set_red(min(255, int(pix.get_red() / factor)))
pix.set_green(min(255, int(pix.get_green() / factor)))
pix.set_blue(min(255, int(pix.get_blue() / factor)))
return new_pic
def test_normalize_brightness():
'''Test the function normalize_brightness in img_manip.'''
new_pic = create_pic(4, 4)
new_pic_normalized= img_manip.normalize_brightness(new_pic)
#The average brightness of new_pic_normalized will likely not be exactly 128
#because the RBG values are rounded to integer values after being multipled
#by the normalization factor, so the function tests for a difference of less
#than 2 rather than for equality.
new_avg_brightness = avg_bright.average_brightness(new_pic_normalized)
assert abs(new_avg_brightness - 128) < 2, \
"normalize_brightness failed to normalize the picture's average \
def pic_info_GUI (label):
#Assign the picture's information to the variable pic_info
pic_info.set("Picture's width: " + str(label.picture.get_width()) + '\n' + \
"Picture's height: " + str(label.picture.get_height()) + \
'\n' + "Average brightness of the picture: " + \
str(int(avg_br.average_brightness(label.picture))))
