I have a 600x1000 picture, i want to blit bottom part of the picture onto my 600x600 window using pygame

Question

In the game our character jumps on platforms in order to move higher. My game resolution is 600x600. I have a picture that's going to be my background and has resolution of 600x1000. I'm trying to setup a background that progressively moves or changes as we go higher. So that when I get higher, the background shows not the bottom of the original picture (Y-axis 400-1000), but shows, for example, the middle part of the picture (Y-axis 200-800). So far I haven't been able to figure out a way how to blit 600x600 image from 600x1000 image. It's like I want to cut the upper part of the original picture so that it fits. Could you help me with this?

I'm sorry if I didn't explain it properly. How do I blit a non-distorted, smaller-sized image from a bigger-sized image. The background I have in mind should look like from an android game called "Happy Jump".

Thank you for reading. Have a good day.

Answer 1

enter image description here

import pygame
pygame.init()
run = True
surf = pygame.display.set_mode((600, 600))
img = pygame.image.load('image.jpg')
down = -400
center_of_screen = 300
maximum_limit_of_down = 0

class Player(pygame.sprite.Sprite):
    def __init__(self):
        pygame.sprite.Sprite.__init__(self)
        self.image = pygame.Surface((40, 40))
        self.image.fill((255, 0, 0))
        self.rect = self.image.get_rect()
        self.rect.center = (300, 570)
        self.isJump = False
        self.jumpCount = 10

    def update(self):
        global down
        key = pygame.key.get_pressed()
        if key[pygame.K_UP] and not self.isJump:
            self.isJump = True
        if self.isJump:
            if self.rect.y > center_of_screen or (down >= maximum_limit_of_down):
                if self.jumpCount >= 0:
                    self.rect.y = self.rect.y - (self.jumpCount ** 2) * 0.5
                    self.jumpCount -= 1
                else:
                    self.jumpCount = 10
                    self.isJump = False
                if down >= maximum_limit_of_down:
                    down = maximum_limit_of_down
            else:
                if self.jumpCount >= 0:
                    down = down + (self.jumpCount ** 2) * 0.5
                    self.jumpCount -= 1
                else:
                    self.jumpCount = 10
                    self.isJump = False


player = Player()
all_sprite = pygame.sprite.Group()
all_sprite.add(player)
clock = pygame.time.Clock()
while run:
    clock.tick(60)
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            run = False
    surf.fill((0, 0, 0))
    surf.blit(img, (0, down))
    all_sprite.update()
    all_sprite.draw(surf)
    pygame.display.update()

This will help you, sorry for the Image i used whatever i found