CODEWITHSUNDEEP
pythonpygame
user4027821
user4027821

Reputation:

Show and flip image using python

I am trying to encode a String to a QR code. Then show the QR code image on a display using python.

Here is my code:

import pyqrcode
from PIL import Image
import os
import pygame
from time import sleep

qr = pyqrcode.create("This is a string one")
qr.png("QR.png", scale=16)
pygame.init()
WIDTH = 1280
HEIGHT = 1080
scr = pygame.display.set_mode((WIDTH,HEIGHT),0,32)
img = pygame.image.load("QR.png")
scr.blit(img,(0,0))
pygame.display.flip()
sleep(3)

Now I want to display and flip the image in a loop.

I want to do it in a loop as the string ("This is a string one") is not constant. It will be updated (such as, I get string from mysql). When the string updates, I want to display the new QR code image after 3 seconds then flip it, then continue.

But when I put the code in a loop, it crashes and the image does not flip or update.

import pyqrcode

from PIL import Image

import os

import pygame

from time import sleep

while(1):

    qr = pyqrcode.create("Nguyen Tran Thanh Lam")

    qr.png("QR.png", scale=16)

    pygame.init()

    WIDTH = 1280

    HEIGHT = 1080

    scr = pygame.display.set_mode((WIDTH,HEIGHT),0,32)

    img = pygame.image.load("QR.png")

    scr.blit(img,(0,0))

    pygame.display.flip()

    sleep(5)

Update:

After 5 second, pygame-windows not flip. I must use Ctrl-C to Interrupt.

Traceback (most recent call last):
File "qr.py", line 18, in <module>
sleep(5)
KeyboardInterrupt

enter image description here enter image description here Thank you in advance.

Upvotes: 0

Views: 683

Answers (1)

skrx
skrx

Reputation: 20438

pygame.display.flip doesn't flip the image, it updates the display/screen. To actually flip an image you have to use pygame.transform.flip.

There are various other problems, for example you should do the initialization, call pygame.display.set_mode and load the image before the while loop starts. After loading an image, call the convert or convert_alpha method to improve the blit performance: 

img = pygame.image.load("QR.png").convert()

You also need to call pygame.event.pump() or use an event loop for event in pg.event.get():, otherwise the program will freeze because the OS thinks that your program has stopped responding.

To implement a timer you can use pygame.time.get_ticks. time.sleep makes your program unresponsive and should usually not be used in a game.

Here's an example:

import pygame as pg


def main():
    screen = pg.display.set_mode((640, 480))
    clock = pg.time.Clock()  # A clock to limit the frame rate.

    image = pg.Surface((100, 100))
    image.fill((50, 90, 150))
    pg.draw.rect(image, (120, 250, 70), (20, 20, 20, 20))

    previous_flip_time = pg.time.get_ticks()
    done = False

    while not done:
        for event in pg.event.get():
            # Close the window if the users clicks the close button.
            if event.type == pg.QUIT:
                done = True

        current_time = pg.time.get_ticks()
        if current_time - previous_flip_time > 1000:  # 1000 milliseconds.
            # Flip horizontally.
            image = pg.transform.flip(image, True, False)
            previous_flip_time = current_time

        screen.fill((30, 30, 30))
        screen.blit(image, (100, 200))

        # Refresh the display/screen.
        pg.display.flip()
        clock.tick(30)  # Limit frame rate to 30 fps.


if __name__ == '__main__':
    pg.init()
    main()
    pg.quit()

Upvotes: 2

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