If you would prefer the origin of the coordinate system to be shown in the lower left-hand corner, then you can modify the coordinates with a simple method as follows:
import pygame
pygame.init ()
screen_width $=1000$
screen_height $=800$
screen $=$ pygame.display.set_mode ((screen_width,
screen_height))
done $=\mathrm{False}$
white $=$ pygame. $\operatorname{Color}(255,255,255)$
def to_pygame_coordinates (display, x, y) :
return $x$, display.get_height() - y
while not done:
for event in pygame. event.get ():
if event.type $==$ pygame.QUIT:
done $=$ True
screen.set_at (to_pygame_coordinates
(screen, 100,100),
white)
screen.set_at (to_pygame_coordinates
(screen, 200,200),
white)
pygame.display .update ()
pygame.quit ()