def convert_to_greyscale_GUI (label):
'''Implement the function convert_to_gryescale from img_manip.'''
#Clear all the temp pics in front of the current pic current_pic
global temp_label
global current_pic
temp_label = temp_label[0:current_pic+1]
#Implement the function convert_to_greyscale.
label.picture = img_manip.convert_to_greyscale(label.picture)
#Keep a copy of the current pic for the functions Undo and Redo
temp_label.append(label.picture)
current_pic += 1
#Update the label
update_label(label)
def test_convert_to_greyscale():
'''Test the function convert_to_greyscale in img_manip.'''
new_pic = create_pic(4, 4)
new_pic_grey_scale = img_manip.convert_to_greyscale(new_pic)
#Test if the RGB value of each pixel in new_pic_grey_scale is equal. If not,
#the boolean grey_scale is made False.
grey_scale = True
for pix in new_pic_grey_scale:
red = pix.get_red()
green = pix.get_green()
blue = pix.get_blue()
if red != green or green != blue or red != blue:
grey_scale = False
assert grey_scale, \
"covert_to_grey_scale failed to equalize the RGB component of each \
