fullscreen_toggle.py

import pygame
from pygame.locals import *

pygame.init()

RES=(160, 120)

FPS=30
clock = pygame.time.Clock()

# COMMENT OUT EACH OF THESE
# COMMENT THE OTHER OBVIOUSLY
# AND HIT F MULTIPLE TIMES

#screen = pygame.display.set_mode(RES, SCALED)
#screen = pygame.display.set_mode((0,0))
screen = pygame.display.set_mode(RES)

#that last one creates a fullscreen window

#MAIN LOOP

done=False

i=0
j=0

while not done:
    for event in pygame.event.get():
        if event.type == QUIT:
            done = True
        if event.type == KEYDOWN and event.key == K_f:
           pygame.display.toggle_fullscreen()

    i+=1
    i=i%screen.get_width()
    j+=(i%2)
    j=j%screen.get_height()
        
    screen.fill((255,0,255))
    pygame.draw.circle(screen, (0,0,0), (100,100), 20)
    pygame.draw.circle(screen, (0,0,200), (0,0), 10)
    pygame.draw.circle(screen, (200,0,0), (160,120), 30)
    pygame.draw.line(screen, (250,250,0), (0,120), (160,0))
    pygame.draw.circle(screen, (255,255,255), (i,j), 5)

        
    pygame.display.flip()
    clock.tick(FPS)