Minege Minege - 28 days ago 15
Python Question

Python3.5 send object over socket (Pygame cam image)

I want to send a PyGame Image over socket with Python 3.5 and i always got a bug.

I get the image, i pickle it, and then i send it.

In the client, i receive it, i unpickle it, and i show it.

But i've got an error :

fenetre.blit(img, (20, 30))
pygame.error: display Surface quit


Here is my code for the server ( the one wich send image ) :

pygame.init()
pygame.camera.init()
cam = pygame.camera.Camera("/dev/video0", (680, 480))
cam.start()
class Streaming(Thread):


def __init__(self):
Thread.__init__(self)
def run(self):

s = socket.socket()
s.bind(('192.168.1.158', 12801))
s.listen(1)
while True:
sc, info = s.accept()
print("Video client connected : "+str(info))
try:
while True:
image = cam.get_image()
str_img = pickle.dumps(image)
sc.send(str_img)
print(str_img)
print("Sending Image")
time.sleep(0.005)
except Exception as e:
print(str(e))


And the code for the client :

fenetre = pygame.display.set_mode((900, 900))
class Receiving(Thread):


def __init__(self):
Thread.__init__(self)

self.clock = pygame.time.Clock()

def run(self):
global fenetre
si = socket.socket()
si.connect(("192.168.1.158", 12801))
while True:
img = si.recv(4096)
img = pickle.loads(img)
fenetre.blit(img, (20, 30))
pygame.display.flip()
self.clock.tick(60)


Thank in advance !

Answer

I made example which sends surface with current time.

(Pygame can't work with my camera).

It uses struc.pack() to send image size always as 4 bytes before image is send. So client first receives 4 bytes and have image size. Then it can use this information to receive image.

Both use loops to send/receive all the time.

server.py

#!/usr/bin/env python

import pygame
from threading import Thread
import socket
import struct # to send `int` as  `4 bytes`
import time   # for test

# --- constants ---

ADDRESS = ("localhost", 12801)

SURFACE_SIZE = (640, 480)

WHITE = (255, 255, 255)
BLACK = (  0,   0,   0)
GREEN = (  0, 255,   0)

# --- classes ---

class Streaming(Thread):

    def __init__(self):
        Thread.__init__(self)

        pygame.init()

        #pygame.camera.init()
        #self.cam = pygame.camera.Camera("/dev/video0", SURFACE_SIZE)
        #self.cam.start()

        # create surface to imitate camera image
        self.image = pygame.Surface(SURFACE_SIZE)
        self.image_rect = self.image.get_rect()

        # create font to display text on surface
        self.font = pygame.font.Font(None, 50)

    def get_image(self):
        # emulate cam.get_image()

        # get current time as string
        current_time = time.strftime('%H:%M:%S.%s')

        # render surface with text (and center it)
        text = self.font.render(current_time, True, BLACK, GREEN)
        text_rect = text.get_rect(center=self.image_rect.center)

        # clear image and put new text
        self.image.fill(WHITE)
        self.image.blit(text, text_rect)

        return self.image

    def run(self):

        s = socket.socket()

        # solution for: "socket.error: [Errno 98] Address already in use"
        s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)

        s.bind(ADDRESS)
        s.listen(1)

        print("Wait for connection")

        try:
            sc, info = s.accept()
            print("Video client connected:", info)

            while True:
                # get image surface

                #image = self.cam.get_image()
                image = self.get_image()

                # convert surface to string

                img_str = pygame.image.tostring(image, 'RGB')

                print('len:', len(img_str))

                # send string size

                len_str = struct.pack('!i', len(img_str))
                sc.send(len_str)

                # send string image

                sc.send(img_str)

                # wait

                time.sleep(0.5)

        except Exception as e:
            print(e)
        finally:
            # exit
            print("Closing socket and exit")
            sc.close()
            s.close()
            pygame.quit()

# --- main ---

Streaming().run()

client.py

#!/usr/bin/env python

import pygame
from threading import Thread
import socket
import struct

# --- constants ---

ADDRESS = ("localhost", 12801)

SURFACE_SIZE = (640, 480)

# --- classes ---

class Receiving(Thread):

    def __init__(self):
        Thread.__init__(self)

        pygame.init()

        self.screen = pygame.display.set_mode((800, 600))
        self.screen_rect = self.screen.get_rect()

        self.clock = pygame.time.Clock()

    def run(self):
        s = socket.socket()
        s.connect(ADDRESS)

        try:
            running = True
            while running:
                # receive size

                len_str = s.recv(4)
                size = struct.unpack('!i', len_str)[0]

                print('size:', size)

                # receive string

                img_str = b''

                while size > 0:
                    if size >= 4096:
                        data = s.recv(4096)
                    else:
                        data = s.recv(size)

                    if not data:
                        break

                    size -= len(data)
                    img_str += data

                print('len:', len(img_str))

                # convert string to surface

                image = pygame.image.fromstring(img_str, SURFACE_SIZE, 'RGB')
                image_rect = image.get_rect(center=self.screen_rect.center)

                # blit

                self.screen.blit(image, image_rect)
                pygame.display.flip()

                #self.clock.tick(30)

                # wait for ESC or close window

                for event in pygame.event.get():
                    if event.type == pygame.QUIT:
                        running = False
                    elif event.type == pygame.KEYDOWN:
                        if event.key == pygame.K_ESCAPE:
                            running = False

        except Exception as e:
            print(e)
        finally:
            # exit
            print("Closing socket and exit")
            s.close()
            pygame.quit()

# --- main ---

Receiving().run()
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