如果我的描述不完美，请原谅，我在PyQt和Python上仍然很新。如果您对如何改善此问题有任何建议，请告诉我。

我正在尝试使用QPainter绘制Pixmap-QLabel，它是QMainWindow的一部分。 QPainter在循环中被调用，因为图形是在固定的持续时间之后更新的。在Pixmap上绘图按预期方式工作，我遇到的问题是标签始终在新窗口中打开，而不是放置在原始QMainWindow内的QLabel上。

我怀疑这是因为我正在从由QThreadpool对象创建的Worker类对象调用QPainter。如果我从GUI初始化内部调用QPainter，则会按预期将Pixmap标签创建为QMainWindow的一部分。不幸的是，多线程是必需的，因此QLabel更新时GUI保持响应。

GUI本身是使用QtCreator创建的，只需将其加载到脚本中即可。

这是我的代码：

import os
import sys
import time

from PyQt5 import QtWidgets,QtCore,uic
from PyQt5.QtWidgets import QLabel,QPushButton,QMainWindow
from PyQt5.QtGui import QPixmap,QPainter,QPen,QPaintEvent
from PyQt5.QtCore import *

class Ui(QMainWindow):
    def __init__(self):
        super(Ui,self).__init__()
        self.counter = 0

        # load ui which can be designed with Qt Creator
        uic.loadUi("ui/paintEvent_Loop.ui",self)

        # find the QLabel where the picture should be placed
        self.pixmap_label = self.findChild(QtWidgets.QLabel,"pixmap_label")

        # creating the pixmap-label here works as intended
        '''self.draw_label = PixmapLabel(self.pixmap_label)
        self.draw_label.setGeometry(130,50,911,512)
        self.draw_label.show()'''

        self.label = self.findChild(QLabel,"label")

        # find the button with the name "cancel_button"
        self.cancel_button = self.findChild(QtWidgets.QPushButton,"cancel_button")
        self.cancel_button.clicked.connect(self.close_application)

        # find the start_button button
        self.start_button = self.findChild(QtWidgets.QPushButton,"start_button")
        self.start_button.clicked.connect(self.start_loop)

        self.pause_cont_button = self.findChild(QPushButton,"pause_cont_button")
        self.pause_cont_button.clicked.connect(self.toggle_pause_continue)
        self.pause_cont_button.hide()

        # create the QThreadPool object to manage multiple threads
        self.threadpool = QThreadPool()
        print("Multithreading with maximum %d threads" % self.threadpool.maxThreadCount())

        self.run_loop = True

        # show application
        self.show()

    def close_application(self):
        app.quit()

    def toggle_pause_continue(self):
        """
        changes the value of boolean run_loop to pause and continue the loop through the samples in the chosen scene
        :return:
        """
        if self.run_loop:
            self.run_loop = False
        else:
            self.run_loop = True

    def start_loop(self):
        # hide start_button and show pause_cont_button
        self.start_button.hide()
        self.pause_cont_button.show()
        self.pause_cont_button.setCheckable(True)

        # start one further thread managed by threadpool
        worker = Worker()
        self.threadpool.start(worker)


class PixmapLabel(QLabel):

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

    def paintEvent(self,a0: QPaintEvent) -> None:

        # initiate QPainter instance
        painter = QPainter(window.draw_label)

        # open image
        picture = QPixmap(os.getcwd() + '/test-image.png')
        myPicturePixmap = picture.scaled(self.size(),QtCore.Qt.KeepAspectRatio)
        self.setPixmap(myPicturePixmap)

        # draw red box on it
        painter.drawPixmap(self.rect(),myPicturePixmap)
        pen = QPen(Qt.red,3)
        painter.setPen(pen)
        painter.drawRect(10,10,100,100)


class Worker(QRunnable):
    # worker thread
    def __init__(self):
        super().__init__()

    @pyqtSlot()
    def run(self):
        print("Thread start")

        for self.i in range(0,50):

            # create pixmap_label with drawings
            # FIXME: make pixmap-label part of original GUI
            window.draw_label = PixmapLabel(window.pixmap_label)
            window.draw_label.setGeometry(130,512)
            window.draw_label.show()

            window.label.setText(str(self.i))

            while window.run_loop == False:
                time.sleep(0.05)

            # show image for 0.5 seconds,then update image
            time.sleep(0.5)
            window.draw_label.destroy()
            time.sleep(0.05)



        # print in terminal to know that we are finished
        print("Thread complete")


if __name__ == "__main__":
    app = QtWidgets.QApplication(sys.argv)
    window = Ui()
    app.exec_()

我正在使用的图像：