How do I blit a PNG with some transparency onto a surface in Pygame? [duplicate]

http://www.pygame.org/docs/ref/image.html recommends:

For alpha transparency, like in .png images use the convert_alpha() method after loading so that the image has per pixel transparency.

You did not flip the doublebuffer.

import pygamefrom pygame.locals import Colorscreen = pygame.display.set_mode((800, 600))treeImage = pygame.image.load("tree.png").convert_alpha()white = Color('white')while(True):    screen.fill(white)    screen.blit(treeImage, pygame.rect.Rect(0,0, 128, 128))    pygame.display.flip()

This should work for your problem.

Images are represented by "pygame.Surface" objects. A Surface can be created from an image with pygame.image.load:

my_image_surface = pygame.load.image('my_image.jpg')

However, the pygame documentation notes that:

The returned Surface will contain the same color format, colorkey and alpha transparency as the file it came from. You will often want to call convert() with no arguments, to create a copy that will draw more quickly on the screen.
For alpha transparency, like in .png images, use the convert_alpha() method after loading so that the image has per pixel transparency.

Use the convert_alpha() method for best performance:

alpha_image_surface = pygame.load.image('my_icon.png').convert_alpha()

A Surface can be drawn on or blended with another Surface using the blit method. The first argument to blit is the Surface that should be drawn. The second argument is either a tuple (x, y) representing the upper left corner or a rectangle. With a rectangle, only the upper left corner of the rectangle is taken into account. It should be mentioned that the window respectively display is also represented by a Surface. Therefore, drawing a Surface in the window is the same as drawing a Surface on a Surface:

window_surface.blit(image_surface, (x, y))

window_surface.blit(image_surface,    image_surface.get_rect(center = window_surface.get_rect().center))

Minimal example: repl.it/@Rabbid76/PyGame-LoadTransparentImage

import pygamepygame.init()window = pygame.display.set_mode((300, 300))clock = pygame.time.Clock()pygameSurface = pygame.image.load('Porthole.png').convert_alpha()background = pygame.Surface(window.get_size())ts, w, h, c1, c2 = 50, *window.get_size(), (160, 160, 160), (192, 192, 192)tiles = [((x*ts, y*ts, ts, ts), c1 if (x+y) % 2 == 0 else c2) for x in range((w+ts-1)//ts) for y in range((h+ts-1)//ts)]for rect, color in tiles:    pygame.draw.rect(background, color, rect)run = Truewhile run:    clock.tick(60)    for event in pygame.event.get():        if event.type == pygame.QUIT:            run = False    window.blit(background, (0, 0))    window.blit(pygameSurface, pygameSurface.get_rect(center = window.get_rect().center))    pygame.display.flip()pygame.quit()exit()