嗨，我之前也用QPainterPath做过类似的自定义图形，结合你提供的示例图，我写了一份完整的可运行代码示例，效果应该和你要的匹配：

import sys
from PyQt5.QtWidgets import QWidget, QApplication
from PyQt5.QtGui import QPainter, QPainterPath, QPen, QBrush
from PyQt5.QtCore import Qt

class CustomShapeWidget(QWidget):
    def __init__(self):
        super().__init__()
        self.setWindowTitle("QPainterPath Custom Shape")
        self.resize(400, 300)

    def paintEvent(self, event):
        painter = QPainter(self)
        painter.setRenderHint(QPainter.Antialiasing)  # 开启抗锯齿，让图形边缘更平滑

        # 创建路径对象
        path = QPainterPath()

        # 定义图形的基础参数（可按需调整）
        start_x, start_y = 100, 100
        shape_width, shape_height = 200, 120
        corner_radius = 15
        arrow_tip_width = 30

        # 开始构建路径
        path.moveTo(start_x + corner_radius, start_y)
        # 绘制上边直线到箭头左侧
        path.lineTo(start_x + shape_width - arrow_tip_width, start_y)
        # 绘制箭头顶部斜线
        path.lineTo(start_x + shape_width, start_y + shape_height // 2)
        # 绘制箭头底部斜线
        path.lineTo(start_x + shape_width - arrow_tip_width, start_y + shape_height)
        # 绘制下边直线到右下角圆角起点
        path.lineTo(start_x + corner_radius, start_y + shape_height)
        # 绘制左下角圆角
        path.arcTo(start_x, start_y + shape_height - 2*corner_radius, 
                   2*corner_radius, 2*corner_radius, 0, 90)
        # 绘制左边直线到左上角圆角起点
        path.lineTo(start_x, start_y + corner_radius)
        # 绘制左上角圆角
        path.arcTo(start_x, start_y, 2*corner_radius, 2*corner_radius, 90, 90)

        # 设置描边画笔
        pen = QPen(Qt.black, 2)
        painter.setPen(pen)
        # 设置填充画刷
        brush = QBrush(Qt.lightGray)
        painter.setBrush(brush)

        # 绘制最终路径
        painter.drawPath(path)

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

一些说明： #

• 这个实现是带圆角的箭头形状，和你提供的示例图风格一致。你可以通过修改代码里的参数（比如corner_radius调整圆角大小，arrow_tip_width调整箭头宽度）来适配你的需求。
• 核心用到了QPainterPath的几个方法：moveTo()设置路径起点，lineTo()绘制直线段，arcTo()绘制圆弧来实现圆角效果。
• 开启抗锯齿是为了避免图形边缘出现锯齿感，让整体更美观。

内容的提问来源于stack exchange，提问作者V.Nosov