Pygame WINDOWRESIZED黑屏

Question

I'm trying to resize a window in pygame but only get a black screen. See the before and after pictures below. What am I doing wrong?

import pygame as pg
from pygame.locals import *

pg.init()

yellow = (255, 255, 134)
grey = (142, 142, 142)

square_size = 100
width = 7 * square_size
height = 7 * square_size
radius = int(square_size / 2 - 10)

screen = pg.display.set_mode((width, height), RESIZABLE)

screen.fill(grey)

pg.draw.circle(screen,yellow,(square_size,square_size),radius)

pg.display.flip()

while True:
    for ev in pg.event.get():
        if ev.type == pg.QUIT:
            print("quit game")
            pg.quit()
            sys.exit()
        if ev.type == pg.WINDOWRESIZED:
            width, height = screen.get_width(), screen.get_height()
    pg.display.flip()

Answer 1

You need to redraw the scene after resizing the window. I recommend redrawing the scene in each frame. The typical PyGame application loop has to:

• limit the frames per second to limit CPU usage with pygame.time.Clock.tick
• handle the events by calling 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 calling either pygame.display.update() or pygame.display.flip()

import sys
import pygame as pg
from pygame.locals import *

pg.init()

yellow = (255, 255, 134)
grey = (142, 142, 142)

square_size = 100
width = 7 * square_size
height = 7 * square_size
radius = int(square_size / 2 - 10)

screen = pg.display.set_mode((width, height), RESIZABLE)
clock = pg.time.Clock()

run = True
while run:

    # limit the frames per second 
    clock.tick(100)

    # handle the events
    for ev in pg.event.get():
        if ev.type == pg.QUIT:
            print("quit game")
            run = False
        if ev.type == pg.WINDOWRESIZED:
            width, height = screen.get_width(), screen.get_height()
    
    # clear display
    screen.fill(grey)

    # draw scene
    pg.draw.circle(screen,yellow,(square_size,square_size),radius)

    # update the display
    pg.display.flip()

pg.quit()
sys.exit()