Pygame not bliting images when pressing key

Question

So, I'm trying to make a game, and I'm working on the basics, I'm trying to figure out why is when I press the 0 key, it prints "a", but the image on the screen doesn't change. This is the same when pressing one too.

import pygame
from pygame.display import mode_ok

pygame.init()
size = width, height = 1000, 800
speed = [2, 2]
black = 1, 2, 0
screen = pygame.display.set_mode(size)
mode_ok(size, flags=1, depth=5, display=0)
DISPLAYSURF = pygame.display.set_mode((0, 0), pygame.FULLSCREEN)

pygame.display.set_caption('Game')
# image database
pic = pygame.image.load(r"intro_ball.gif")
pic2 = pygame.image.load("poeple.png")
pic3 = pygame.image.load("frame_04_delay-0.1s.gif")
pic4 = pygame.image.load("frame_17_delay-0.1s.gif")
screen.blit(pygame.transform.scale(pic, (1000, 800)), (0, 0))
screen.blit(pic2, (500, 400))
pygame.display.flip()


while True:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            pygame.quit()
        if event.type == pygame.KEYDOWN:
            if event.key == pygame.K_0:
                screen.blit(pic3, (0, 0))
                print("a")
            if event.key == pygame.K_1:
                screen.blit(pygame.transform.scale(pic4, (1000, 800)), (0, 0))
                print("B")
    pygame.event.pump()

If anyone can help, that would be greatly appreciated.

score 0 · Accepted Answer · answered Apr 05 '21 at 13:16

The event loop runs only once when the event occurs. When an image is drawn in the event loop, it is only visible for a brief moment. If you want to draw the pictures permanently, you need to draw them in the application loop.
Set the current picture to a current_pic variable. Change the variable when the event occurs. Continuously draw the picture indicated by the current_pic variable in the application loop:

current_pic = pygame.transform.scale(pic, (1000, 800))

clock = pygame.time.Clock()
run = True
while True:
    clock.tick(60)
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            run = False
        if event.type == pygame.KEYDOWN:
            if event.key == pygame.K_0:
                current_pic = pic3
                print("a")
            if event.key == pygame.K_1:
                current_pic = pygame.transform.scale(pic4, (1000, 800))
                print("B")
    
    screen.blit(current_pic, (0, 0))
    screen.blit(pic2, (500, 400))
    pygame.display.flip()

pygame.quit()

The typical PyGame application loop has to:

handle the events by either pygame.event.pump() or pygame.event.get().
update the game states and positions of objects dependent on the input events and time (respectively frames)
clear the entire display or draw the background
draw the entire scene (blit all the objects)
update the display by either pygame.display.update() or pygame.display.flip()
limit frames per second to limit CPU usage

Pygame not bliting images when pressing key

1 Answers1