如何在单个 PyQt GUI 实例中多处理多个绘图

Question

我有一个名为CrosshairPlotWidget 的绘图对象。每个绘图对象都会产生一个更新其数据的线程，但这些线程仍在同一个主 GUI 进程中。这是我目前拥有的和插图：

1 个带有 2 个线程的主 GUI 进程

我想在单独的进程中运行这两个绘图，但都在同一个 GUI 实例中（同一个窗口）。本质上，我试图将每个情节放入自己单独的子进程中，以实现真正的并发，因为我的 CPU 瓶颈。通过将每个更新线程放在一个单独的进程中，它将绕过 Python 的全局解释器锁。以下是预期目标的图示：

1 个主 GUI 进程和 2 个子进程，每个子进程都有自己的线程

我看过

• Implementing pyqtgraph multiprocessing into a pyqt widget

• multiprocessing and GUI updating - Qprocess or multiprocessing?

• PyQt MainWindow using multiprocessing on Windows

• Python: multiprocessing in pyqt application

但对我的情况没有任何帮助。

我还发现 this 进行多处理但不在同一个 GUI 窗口中。

from PyQt4 import QtCore, QtGui
import multiprocessing as mp
from threading import Thread
import pyqtgraph as pg
import numpy as np
import sys
import random
import time

class CrosshairPlotWidget(QtGui.QWidget):
    """Scrolling plot with crosshair"""

    def __init__(self, parent=None):
        super(CrosshairPlotWidget, self).__init__(parent)

        # Use for time.sleep (s)
        self.FREQUENCY = .025
        # Use for timer.timer (ms)
        self.TIMER_FREQUENCY = self.FREQUENCY * 1000

        self.LEFT_X = -10
        self.RIGHT_X = 0
        self.x_axis = np.arange(self.LEFT_X, self.RIGHT_X, self.FREQUENCY)
        self.buffer = int((abs(self.LEFT_X) + abs(self.RIGHT_X))/self.FREQUENCY)
        self.data = []

        self.crosshair_plot_widget = pg.PlotWidget()
        self.crosshair_plot_widget.setXRange(self.LEFT_X, self.RIGHT_X)
        self.crosshair_plot_widget.setLabel('left', 'Value')
        self.crosshair_plot_widget.setLabel('bottom', 'Time (s)')
        self.crosshair_color = (101,255,183)

        self.crosshair_plot = self.crosshair_plot_widget.plot()

        self.layout = QtGui.QGridLayout()
        self.layout.addWidget(self.crosshair_plot_widget)

        self.crosshair_plot_widget.plotItem.setAutoVisible(y=True)
        self.vertical_line = pg.InfiniteLine(angle=90)
        self.horizontal_line = pg.InfiniteLine(angle=0, movable=False)
        self.vertical_line.setPen(self.crosshair_color)
        self.horizontal_line.setPen(self.crosshair_color)
        self.crosshair_plot_widget.setAutoVisible(y=True)
        self.crosshair_plot_widget.addItem(self.vertical_line, ignoreBounds=True)
        self.crosshair_plot_widget.addItem(self.horizontal_line, ignoreBounds=True)

        self.crosshair_update = pg.SignalProxy(self.crosshair_plot_widget.scene().sigMouseMoved, rateLimit=60, slot=self.update_crosshair)

        self.update_data_thread = Thread(target=self.plot_updater, args=())
        self.update_data_thread.daemon = True
        self.update_data_thread.start()

    def plot_updater(self):
        """Updates data buffer with data value"""

        while True:
            self.data_point = random.randint(1,101)
            if len(self.data) >= self.buffer:
                del self.data[:1]
            self.data.append(float(self.data_point))
            self.crosshair_plot.setData(self.x_axis[len(self.x_axis) - len(self.data):], self.data)
            time.sleep(self.FREQUENCY)

    def update_crosshair(self, event):
        """Paint crosshair on mouse"""

        coordinates = event[0]  
        if self.crosshair_plot_widget.sceneBoundingRect().contains(coordinates):
            mouse_point = self.crosshair_plot_widget.plotItem.vb.mapSceneToView(coordinates)
            index = mouse_point.x()
            if index > self.LEFT_X and index <= self.RIGHT_X:
                self.crosshair_plot_widget.setTitle("<span style='font-size: 12pt'>x=%0.1f,   <span style='color: red'>y=%0.1f</span>" % (mouse_point.x(), mouse_point.y()))
            self.vertical_line.setPos(mouse_point.x())
            self.horizontal_line.setPos(mouse_point.y())

    def get_crosshair_plot_layout(self):
        return self.layout

if __name__ == '__main__':
    # Create main application window
    app = QtGui.QApplication([])
    app.setStyleSheet("""
        QWidget {
            background-color: #19232D;
            border: 0px solid #32414B;
            padding: 0px;
            color: #F0F0F0;
            selection-background-color: #1464A0;
            selection-color: #F0F0F0;
        }""")
    app.setStyle(QtGui.QStyleFactory.create("Cleanlooks"))
    mw = QtGui.QMainWindow()
    mw.setWindowTitle('Crosshair Plot')

    # Create and set widget layout
    # Main widget container
    cw = QtGui.QWidget()
    ml = QtGui.QGridLayout()
    cw.setLayout(ml)
    mw.setCentralWidget(cw)

    # Create crosshair plot
    crosshair_plot1 = CrosshairPlotWidget()
    crosshair_plot2 = CrosshairPlotWidget()

    ml.addLayout(crosshair_plot1.get_crosshair_plot_layout(),0,0,1,1)
    ml.addLayout(crosshair_plot2.get_crosshair_plot_layout(),0,1,1,1)
    mw.show()

    ## Start Qt event loop unless running in interactive mode or using pyside.
    if (sys.flags.interactive != 1) or not hasattr(QtCore, 'PYQT_VERSION'):
        QtGui.QApplication.instance().exec_()

Answer 1

GUI只能存在于属于主进程的主线程中，所以你所要求的是不可能的。正如您在其他示例中看到的，最接近您想要的是在另一个进程中生成实时数据的代码

         Child Process 1               Child Process 2
        ┌----------------┐           ┌----------------┐  
        | ┌-----------┐  |           | ┌-----------┐  |
        | | Producer1 |  |           | | Producer2 |  |
        | └-----------┘  |           | └-----------┘  |
        └-------┬--------┘           └-------┬--------┘   
                |                            |
                └---------------┬------------┘
                                |
                       ┌--------┴--------┐ 
                       |  Main Thread    |
                       |  ┌-----------┐  | 
                       |  |    GUI    |  |
                       |  └-----------┘  | 
                       └-----------------┘
                          Main Process