How to reset rectangle position in the moment when it touches the border?

Question

Problem is, whatever i tried to put in this part of the code:

 LOPTICA = LOPTICA.move(BRZINA_LOPTICE)
 if LOPTICA.left < 0 or LOPTICA.right > width:
  ##what i should put here 

It got crashed application or ball ("LOPTICA") went out of the screen instead of getting back in the default position.

I need some variable or function to put in this, so ball ("LOPTICA") and the rest of the game get reset to the default positions.

import pygame
import os

width, height = 900, 500
screen = pygame.display.set_mode((width, height))

FPS = 60
BRZINA = 6
x = 450
y = 250
BRZINA_LOPTICE = [4.5, 4.5]


ikonica = pygame.image.load(os.path.join('dodaci', "ikonica.png"))
ime = pygame.display.set_caption('Ping Pong')
ikonica_u_igri = pygame.display.set_icon(ikonica)

pozadina = pygame.image.load(os.path.join('dodaci', 'pozadina.jpg'))
BOJALINIJE = (255, 255, 255)
BOJALOPTICE = (224, 15, 0)

LEVALINIJA = pygame.Rect(100, 220, 7, 100)
DESNALINIJA= pygame.Rect(800, 220, 7, 100)
radius= 10

LOPTICA = pygame.Rect(width//2, height//2, radius*2, radius)


def prikaz_pozadine():
    screen.blit(pozadina, (0, 0))
    pygame.draw.rect(screen, BOJALINIJE, LEVALINIJA)
    pygame.draw.rect(screen, BOJALINIJE, DESNALINIJA)
    pygame.draw.circle(screen, BOJALOPTICE, LOPTICA.center, radius)
    pygame.display.update()


def kretanje_linija(LEVALINIJA, DESNALINIJA):
    tasteri_kretanja = pygame.key.get_pressed()

    if tasteri_kretanja[pygame.K_w] and LEVALINIJA.y - BRZINA > 0:
        LEVALINIJA.y -= BRZINA
    if tasteri_kretanja[pygame.K_s] and LEVALINIJA.y + BRZINA + LEVALINIJA.height < height:
        LEVALINIJA.y += BRZINA
    if tasteri_kretanja[pygame.K_UP] and DESNALINIJA.y - BRZINA > 0:
        DESNALINIJA.y -= BRZINA
    if tasteri_kretanja[pygame.K_DOWN] and DESNALINIJA.y + BRZINA + LEVALINIJA.height < height:
        DESNALINIJA.y += BRZINA


def glavnica():
    clock = pygame.time.Clock()
    running = True
    while running:
        global LOPTICA
        clock.tick(FPS)
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                running = False

        LOPTICA = LOPTICA.move(BRZINA_LOPTICE)
        if LOPTICA.left < 0 or LOPTICA.right > width:
            ##what i should put here ?
        if LOPTICA.top < 0 or LOPTICA.bottom > height:
            BRZINA_LOPTICE[1] = -BRZINA_LOPTICE[1]

        if LOPTICA.colliderect(LEVALINIJA):
            BRZINA_LOPTICE[0] = abs(BRZINA_LOPTICE[0])

        if LOPTICA.colliderect(DESNALINIJA):
            BRZINA_LOPTICE[0] = -abs(BRZINA_LOPTICE[0])

        prikaz_pozadine()
        kretanje_linija(LEVALINIJA, DESNALINIJA)


if __name__ == "__main__":
    glavnica()`

Answer 1

Just set the initial position of the rectangle:

if LOPTICA.left < 0 or LOPTICA.right > width:
    LOPTICA.topleft = (width//2, height//2)

Note, a pygame.Rect addresses the top left corner of the rectangle. If you assign a tuple with 2 coordinates to topleft, the rectangle will be modified so that the top left corner is at that position.