如何在PyQt5中实现用于渲染的形状选择面板？

我在设计图形编辑器。作为绘图的场景，我需要完全使用QGraphicsScene。我实现了向场景中添加矩形和椭圆。然而，我无法理解特殊面板与形状的实现。使用PyQt5（此面板取自Paint）在Python中选择图形的绘制需要实现以下面板：形状选择面板1

还需要实现将图形从面板拖动到画布，大致如图所示：形状选择面板2

此自定义面板可以使用哪些小部件或按钮？也许有一个信息资源或类似小组的实施示例？

具有添加形状和界面图像的实现的程序代码：

from PyQt5.QtWidgets import *
from PyQt5.QtGui import *
from PyQt5.QtCore import *
import sys                                                                                                                      

# window class
class Window(QMainWindow):
    def __init__(self):
        super().__init__()

        wid = QWidget()
        self.setCentralWidget(wid)

        # setting title
        self.setWindowTitle("Paint with PyQt5")

        # setting geometry to main window
        self.setGeometry(100, 100, 800, 600)


        # Defining a scene rect of 400x200, with it's origin at 0,0.
        # If we don't set this on creation, we can set it later with .setSceneRect
        self.scene = QGraphicsScene(0, 0, 400, 200)

        # Set all items as moveable and selectable.
        for item in self.scene.items():
            item.setFlag(QGraphicsItem.ItemIsMovable)
            item.setFlag(QGraphicsItem.ItemIsSelectable)

        # Define our layout.
        vbox = QVBoxLayout()

        up = QPushButton("Rect")
        up.clicked.connect(self.add_rect)
        vbox.addWidget(up)

        down = QPushButton("Elips")
        down.clicked.connect(self.add_elips)
        vbox.addWidget(down)

        view = QGraphicsView(self.scene)
        view.setRenderHint(QPainter.Antialiasing)

        hbox = QHBoxLayout(self)
        hbox.addLayout(vbox)
        hbox.addWidget(view)

        wid.setLayout(hbox)

    def add_rect(self):
        rect = QGraphicsRectItem(0, 0, 200, 50)
        rect.setPos(50, 20)
        rect.setFlag(QGraphicsItem.ItemIsMovable)
        rect.setFlag(QGraphicsItem.ItemIsSelectable)
        self.scene.addItem(rect)

    def add_elips(self):
        ellipse = QGraphicsEllipseItem(0, 0, 100, 100)
        ellipse.setPos(75, 30)
        ellipse.setFlag(QGraphicsItem.ItemIsMovable)
        ellipse.setFlag(QGraphicsItem.ItemIsSelectable)
        self.scene.addItem(ellipse)


# create pyqt5 app
App = QApplication(sys.argv)

# create the instance of our Window
window = Window()

# showing the window
window.show()

# start the app
sys.exit(App.exec())

界面图像：界面图像