**Topic: Advanced Custom Widgets with PyQt6 and Animation** In this example, we'll create a custom animated circular progress bar using PyQt6 and Python. This widget can be used in various applications to display a progress indicator in a visually appealing way. **Prerequisites** * Python 3.8+ * PyQt6 (latest version) * pip (Python package installer) **Installation and Setup** If you haven't installed PyQt6 yet, you can do so using pip: ```bash pip install PyQt6 ``` **Custom Animated Circular Progress Bar** Here's the code for the custom circular progress bar widget: ```python import sys import math from PyQt6.QtCore import * from PyQt6.QtGui import * from PyQt6.QtWidgets import * class AnimatedCircularProgress(QProgressBar): def __init__(self): super().__init__() self._angle = 0 self._sweep_angle = 360 self.setFixedSize(100, 100) self.setStyleSheet("border: none;") self.setFormat("%p%") self.setAlignment(Qt.AlignmentFlag.AlignCenter) self.setRange(0, 100) def paintEvent(self, e): painter = QPainter(self) painter.setRenderHint(painter.RenderHint.Antialiasing) center_x = self.width() // 2 center_y = self.height() // 2 radius = min(center_x, center_y) - 10 painter.setPen(QPen(Qt.GlobalColor.black, 2)) painter.setBrush(Qt.BrushStyle.NoBrush) painter.drawEllipse(center_x - radius, center_y - radius, radius * 2, radius * 2) painter.setPen(QPen(Qt.GlobalColor.blue, 5)) painter.setBrush(Qt.BrushStyle.NoBrush) painter.save() painter.translate(center_x, center_y) painter.rotate(90) path = QPainterPath() path.arcBy(0, 0, radius, 0, self._sweep_angle) painter.drawPath(path) painter.restore() painter.setPen(QPen(Qt.GlobalColor.black, 2)) painter.drawText(QPointF(center_x, center_y), f"{self.value()}%") def set_sweep_angle(self, value): self._sweep_angle = value self.update() def animate_progress(self): if self._angle < 360: self._angle += 10 self.set_sweep_angle(self._angle) QTimer.singleShot(100, self.animate_progress) class Window(QWidget): def __init__(self): super().__init__() self.initUI() def initUI(self): self.setGeometry(100, 100, 400, 300) self.setWindowTitle("Animated Circular Progress") progress_bar = AnimatedCircularProgress() progress_bar.animate_progress() layout = QVBoxLayout() layout.addWidget(progress_bar) self.setLayout(layout) if __name__ == "__main__": app = QApplication(sys.argv) window = Window() window.show() sys.exit(app.exec()) ``` **How it works** 1. We create a custom class `AnimatedCircularProgress` inheriting from `QProgressBar`. We override the `paintEvent` method to draw the circular progress bar. 2. In the `paintEvent`, we draw two ellipses, one for the background ring and another for the progress arc. We also draw the percentage text at the center. 3. We add the `set_sweep_angle` and `animate_progress` methods to animate the progress bar. The `animate_progress` method is recursively called using `QTimer` to create the animation effect. 4. In the `Window` class, we create an instance of `AnimatedCircularProgress` and call its `animate_progress` method to start the animation. **Output** When you run the code, you'll see an animated circular progress bar with a blue arc and a percentage text at the center. **Expert Tips and Variations** * You can customize the appearance of the progress bar by modifying the colors, border, and radius in the `paintEvent` method. * To change the animation speed, you can adjust the value in `QTimer.singleShot`. * You can also add more complex animations or add support for different progress bar styles by implementing more methods in the `AnimatedCircularProgress` class. By using this custom animated circular progress bar, you can add a unique visual element to your application and create a compelling user experience.