PyQtGraph中的旋钮小部件(或备用部件)

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

class KnobWidget(QWidget):
    def __init__(self, parent=None):
        super().__init__(parent)
        self.value = 0
        self.min_value = 0
        self.max_value = 100

    def paintEvent(self, event):
        painter = QPainter(self)
        painter.setRenderHint(QPainter.Antialiasing)
        center = QPointF(self.width() / 2, self.height() / 2)
        radius = min(self.width(), self.height()) / 2 - 10
        angle_range = 2 * 3.14159 * (self.max_value - self.min_value) / 360
        start_angle = -3.14159 * (self.min_value / 360)
        end_angle = start_angle + angle_range

        # Draw the knob outline
        painter.setPen(QPen(Qt.black, 2))
        painter.drawArc(center.x() - radius, center.y() - radius, 2 * radius, 2 * radius,
                         start_angle * 180 / 3.14159, (end_angle - start_angle) * 180 / 3.14159)

        # Draw the indicator
        indicator_angle = start_angle + (self.value - self.min_value) / (self.max_value - self.min_value) * angle_range
        painter.setBrush(QBrush(Qt.blue))
        painter.drawPie(center.x() - radius, center.y() - radius, 2 * radius, 2 * radius,
                        indicator_angle * 180 / 3.14159, 20 * 180 / 3.14159)

    def mousePressEvent(self, event):
        if event.button() == Qt.LeftButton:
            self.update_value(event.pos())

    def mouseMoveEvent(self, event):
        if event.buttons() & Qt.LeftButton:
            self.update_value(event.pos())

    def update_value(self, pos):
        center = QPointF(self.width() / 2, self.height() / 2)
        radius = min(self.width(), self.height()) / 2 - 10
        dx = pos.x() - center.x()
        dy = pos.y() - center.y()
        angle = 3.14159 - 3.14159 * (2 * dx / (2 * radius))
        self.value = int((angle - (-3.14159 * (self.min_value / 360))) / (2 * 3.14159) * (self.max_value - self.min_value) + self.min_value)
        self.update()

class MainWindow(QWidget):
    def __init__(self):
        super().__init__()
        layout = QVBoxLayout()
        self.knob = KnobWidget()
        layout.addWidget(self.knob)
        self.setLayout(layout)

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