如何在单个PyQt GUI实例中多处理多个图

Question

我有一个名为CrosshairPlotWidget的情节对象。每个绘图对象生成一个更新其数据的线程，但这些线程仍在同一主GUI过程中。这是我目前拥有的和插图：

1个主要GUI进程，包含2个线程

我想在一个单独的进程中运行这两个图，但都在同一个GUI实例（同一个窗口）中。本质上，我正在尝试将每个绘图放入其自己的独立子进程中以实现真正的并发性，因为我是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。以下是预期目标的说明：

1个主GUI过程，包含2个子进程，每个进程都有自己的线程

我看了看

• 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

但在我的情况下没有一个真正有用。

我还发现this可以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，因此无法满足您的需求。正如您在其他示例中看到的那样，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