如何基于QTimer更新QPainter像素图

from PyQt5.QtWidgets import QApplication, QWidget
from PyQt5.QtGui import QPainter, QColor, QPen
from PyQt5.QtCore import Qt, QTimer

class MyWidget(QWidget):
    def __init__(self):
        super().__init__()
        self.timer = QTimer(self)
        self.timer.timeout.connect(self.update)  # 每次定时器超时时触发更新
        self.timer.start(100)  # 设置定时器间隔为100毫秒

    def paintEvent(self, event):
        painter = QPainter(self)
        painter.setRenderHint(QPainter.Antialiasing)  # 设置抗锯齿渲染
        self.drawPixelMap(painter)  # 调用自定义的绘制像素图方法

    def drawPixelMap(self, painter):
        # 在这里进行像素图的绘制操作
        # 可以使用QPainter的各种绘制函数来绘制图形、文本等
        # 例如，绘制一个红色的矩形：
        painter.setPen(QPen(Qt.red))
        painter.setBrush(QColor(255, 0, 0))
        painter.drawRect(50, 50, 100, 100)

app = QApplication([])
widget = MyWidget()
widget.show()
app.exec_()