how to use pygame set_alpha() on a picture

Question

I am using pygame and python for a project I am building, and I am building a splashscreen for when the game first opens. I have a .png that I want to show for the splashscr

Answer 1

[1] You don't want to load the image every iteration. Because creating a new surface is a slow operation. [2] Your loop draws 225 times, then afterward the final iteration, waits 2000ms.

You want:

image = pygame.image.load("logo.png")

for i in range (225):
    background.fill((0,0,0))    
    image.set_alpha(i)
    screen.blit(image,(0,0))
    pygame.display.flip()
    pygame.time.delay(20)

To fade in and out, you need to keep looping until the player clicks/hits a button. Like this:

import pygame
from pygame.locals import *

# ...

def title_loop():
    # title screen main loop    
    image = pygame.image.load("logo.png")
    done = False
    alpha = 0
    alpha_vel = 1

    # fade alpha in-out while waiting    
    while not done:        
        # get key input
        for event in pygame.event.get():
            if event.type == QUIT:
                done = true
            if event.type == KEYDOWN:
                if event.key = K_ESCAPE:
                    done = true

        # draw
        if alpha >= 255 or alpha <= 0:
            alpha_vel *= -1
        alpha += alpha_vel

        background.fill((0,0,0))
        image.set_alpha(i)
        screen.blit(image,(0,0))
        pygame.display.flip()

        pygame.time.delay(20)