pyqt 多线程：为什么工作线程阻塞主线程

如何解决pyqt 多线程：为什么工作线程阻塞主线程

当我尝试加载一些 size>10MB 或 pages>300 的 .pdf 时，

工作线程会阻塞主线程，我不知道如何正确使用QThread，

我希望每次 pixmap_page_load 运行时，都将信号发送到主线程。

这里是最少的代码，需要模块pymupdf和一个pdf文件

import time

from PyQt5.QtCore import QRectF,Qt,pyqtSignal,QThread
from PyQt5.QtGui import QColor,QBrush,QPen,QImage,Qpixmap
from PyQt5.QtWidgets import QApplication,QGraphicslineItem,QMainWindow,QGraphicsScene,QGraphicsView,QGraphicsItem,\
    QFileDialog

from fitz import fitz

def pixmap_page_load(doc:"fitz.Document",pagenum,ratio=1):

    page:"fitz.Page" = doc.load_page(pagenum)  # 加载的是页面
    pix:"fitz.pixmap" = page.getpixmap(matrix=fitz.Matrix(ratio,ratio))  # 将页面渲染为图片
    fmt = QImage.Format_RGBA8888 if pix.alpha else QImage.Format_RGB888  # 渲染的格式

    pageImage = QImage(pix.samples,pix.width,pix.height,pix.stride,fmt)
    pixmap = Qpixmap()
    pixmap.convertFromImage(pageImage)  # 转为pixmap
    return Qpixmap(pixmap)

class MyGraphicRect2(QGraphicsItem):
    def __init__(self,x,y,width,height):
        super().__init__()
        self.x = x
        self.y = y
        self.width = width
        self.height = height
        self.setPos(self.x,self.y)
        self.color = QColor('red')

        self.setAcceptDrops(True)
        self.setCursor(Qt.OpenHandCursor)
        self.setFlag(QGraphicsItem.ItemIsSelectable,True)
        self.setFlag(QGraphicsItem.ItemIsMovable,True)
        self.setFlag(QGraphicsItem.ItemIsFocusable,True)
        self.setAcceptHoverEvents(True)

    def setColor(self,color):
        self.color = QColor(color)

    def boundingRect(self):
        return QRectF(self.x,self.y,self.width,self.height)

    def paint(self,painter,options,widget):
        painter.setPen(QPen(QColor('black')))
        painter.setBrush(self.color)
        painter.drawRect(self.x,self.height)


class MoveThread(QThread):
    s = pyqtSignal(float,float)
    def __init__(self,directory):
        super().__init__()
        self.directory=directory
    def run(self):

        doc= fitz.open(self.directory)
        for i in range(1,len(doc)):
            pixmap = pixmap_page_load(doc,i)
            self.s.emit(i,0)


class MyGraphicScene(QMainWindow):
    def __init__(self):
        super().__init__()
        self.rect=QRectF(0,800,800)
        self.Scene=QGraphicsScene(self.rect)
        self.View=QGraphicsView()
        self.View.setCacheMode(QGraphicsView.CacheNone)
        self.sceneConfig()
        self.displayUI()

    def sceneConfig(self):
        self.Scene.setBackgroundBrush(QBrush(QColor('yellow'),Qt.solidPattern))

        self.item1=MyGraphicRect2(100,100,100)
        self.Scene.addItem(self.item1)
        line=QGraphicslineItem(80,38,84,38)
        self.Scene.addItem(line)
        self.View.setScene(self.Scene)

    def updatePosition(self,y):
        item1 = MyGraphicRect2(100+x,100+y,100)
        self.Scene.addItem(item1)

    def displayUI(self):
        print('Is scene active',self.Scene.isActive())
        directory,_ = QFileDialog.getopenFileName(None,"选取文件",".","(*.pdf)")
        self.setCentralWidget(self.View)
        self.th=MoveThread(directory)
        self.th.s.connect(self.updatePosition)
        self.th.start()
        self.resize(1000,1000)
        self.show()

if __name__ == "__main__":
    import sys
    app=QApplication(sys.argv)

    m=MyGraphicScene()

    sys.exit(app.exec_())