Why that (x+w)(y+h)

[DevloperHS]

I DONT GET THIS LINE , WHAT IS THE NEED OF
cv2.rectangle(test_image, (x, y), (x+w, y+h), (0, 255, 0), 2)

That (x+w, y+h) one

As if you go for that Integral Images' concept the cords should be like be like

(x+w-(y+h))

So please help me understand , what this line doing

(x+w, y+h)