添加滚动条以在绘制多个图形时保留PyQt5中的图形大小

import sys
from PyQt5.QtWidgets import QApplication, QMainWindow, QWidget, QVBoxLayout, QLabel, QScrollArea
from PyQt5.QtGui import QPainter, QColor, QPen
from PyQt5.QtCore import Qt

class GraphicsWidget(QWidget):
    def __init__(self):
        super().__init__()
        self.setMinimumSize(500, 500)

    def paintEvent(self, event):
        painter = QPainter(self)
        painter.setRenderHint(QPainter.Antialiasing)

        # 绘制图形
        pen = QPen(Qt.black, 2)
        painter.setPen(pen)
        painter.setBrush(QColor(255, 0, 0))
        painter.drawRect(50, 50, 100, 100)

        painter.setBrush(QColor(0, 255, 0))
        painter.drawEllipse(200, 200, 100, 100)

        painter.setBrush(QColor(0, 0, 255))
        painter.drawPolygon([Qt.Point(350, 350), Qt.Point(400, 400), Qt.Point(450, 350)])

class MainWindow(QMainWindow):
    def __init__(self):
        super().__init__()
        self.setWindowTitle("Graphics with Scrollbar")
        self.setGeometry(100, 100, 600, 600)

        scroll_area = QScrollArea()
        scroll_area.setWidgetResizable(True)

        widget = GraphicsWidget()
        scroll_area.setWidget(widget)

        layout = QVBoxLayout()
        layout.addWidget(scroll_area)

        central_widget = QWidget()
        central_widget.setLayout(layout)
        self.setCentralWidget(central_widget)

if __name__ == "__main__":
    app = QApplication(sys.argv)
    window = MainWindow()
    window.show()
    sys.exit(app.exec_())