如何使用pyqtgraph和多处理进行绘图？

Question

我正在尝试制作一个产生2个进程的程序，其中一个（sender）每秒向另一个进程（receiver）发送一个随机整数，并使用该值绘制正态（高斯）分布。

import multiprocessing as mp
import time
import random
import os
import numpy as np
import pyqtgraph as pg
from pyqtgraph.Qt import QtGui, QtCore
from pyqtgraph.dockarea import *

class PLT():
    def __init__(self):
        self.win2 = pg.GraphicsWindow(title="Basic plotting examples")
        self.win2.resize(1000,600)
        self.win2.setWindowTitle('pyqtgraph example: Plotting')
        self.p2 = self.win2.addPlot(title="Updating plot")
        self.curve = self.p2.plot(pen='y')

        #QtGui.QApplication.instance().exec_()   # ---> if it's in effect, the plotting window shows up, but the data exchange doesn't happen.

    def update(self, data):
        self.curve.setData(data)

class sender(mp.Process):
    def __init__(self, pipe):
        mp.Process.__init__(self)
        self.pipe = pipe

    def run(self):
        print('SENDER PID: ', os.getpid() )
        while True:
            value = random.randint(0, 10)
            self.pipe.send(value)
            time.sleep(1)

class receiver(mp.Process):
    def __init__(self, pipe):
        mp.Process.__init__(self)
        self.pipe = pipe

    def run(self):
        self.p = PLT()
        print('RECEIVER PID: ', os.getpid() )
        while True:
            integer = self.pipe.recv() 
            print(integer)  

            self.p.update(np.random.normal(size=(10,1000))[integer%10])

if __name__ == '__main__':
    mp.freeze_support()
    print('MAIN PID: ', os.getpid() )

    out_pipe, in_pipe = mp.Pipe() 

    p1 = sender(pipe=in_pipe)
    p2 = receiver(pipe=out_pipe)
    p1.start()
    p2.start()

但它不像我预期的那样有效。如果我运行它，它会显示一个空白的pyqtgraph窗口（但我可以看到数据交换）。如果我添加QtGui.QApplication.instance().exec_()，它会很好地显示窗口，但现在数据交换不起作用。我错了什么？如果我能得到一些建议或帮助，我会很感激。

Answer 1

如果这有帮助，我发现：

import multiprocessing as mp
import time
import random
import os
import numpy as np
import pyqtgraph as pg
from pyqtgraph.Qt import QtGui, QtCore
#from pyqtgraph.dockarea import *

class PLT():
    def __init__(self):
        self.win = pg.GraphicsWindow(title="Basic plotting examples")
        self.win.setWindowTitle('pyqtgraph example: Plotting')
        #self.win.resize(1000,600)
        self.p2 = self.win.addPlot(title="Updating plot")
        self.curve = self.p2.plot(pen='y')

        #QtGui.QApplication.instance().exec_()   # ---> if it's in effect, the plotting window shows up, but the data exchange doesn't happen.

    def update(self, data):
        self.curve.setData(data)
        QtGui.QApplication.processEvents()   # <--- Here is the way to update the window.

class sender(mp.Process):
    def __init__(self, pipe):
        mp.Process.__init__(self)
        self.pipe = pipe

    def run(self):
        print('SENDER PID: ', os.getpid() )
        while True:
            value = random.randint(0, 10)
            self.pipe.send(value)
            time.sleep(.01)

class receiver(mp.Process):
    def __init__(self, pipe):
        mp.Process.__init__(self)
        self.pipe = pipe

    def run(self):
        self.p = PLT()
        print('RECEIVER PID: ', os.getpid() )
        while True:
            integer = self.pipe.recv() 
            print(integer)  

            self.p.update(np.random.normal(size=(10,1000))[integer%10])

if __name__ == '__main__':
    mp.freeze_support()
    print('MAIN PID: ', os.getpid() )

    out_pipe, in_pipe = mp.Pipe() 

    p1 = sender(pipe=in_pipe)
    p2 = receiver(pipe=out_pipe)
    p1.start()
    p2.start()