**Topic: Custom Widgets and Components** In this example, we will create a custom widget using PyQt6 that allows users to select and visualize different shapes. This widget will include a drop-down menu for selecting the shape type, a slider for adjusting the shape's size, and a canvas for rendering the selected shape. **ShapeSelector Widget** ```python import sys from PyQt6.QtWidgets import QWidget, QComboBox, QSlider, QVBoxLayout, QHBoxLayout from PyQt6.QtGui import QPainter, QPen, QBrush from PyQt6.QtCore import Qt class ShapeSelector(QWidget): def __init__(self): super().__init__() self.shape_types = ["Circle", "Rectangle", "Triangle"] self.shape_type = self.shape_types[0] self.shape_size = 100 self.layout = QHBoxLayout() self.setLayout(self.layout) self.shape_dropdown = QComboBox() self.shape_dropdown.addItems(self.shape_types) self.shape_dropdown.currentTextChanged.connect(self.update_shape_type) self.shape_slider = QSlider(Qt.Orientation.Horizontal) self.shape_slider.setMinimum(10) self.shape_slider.setMaximum(200) self.shape_slider.setValue(self.shape_size) self.shape_slider.valueChanged.connect(self.update_shape_size) self.canvas = ShapeCanvas() self.layout.addWidget(self.shape_dropdown) self.layout.addWidget(self.shape_slider) self.layout.addWidget(self.canvas) def update_shape_type(self, shape_type): self.shape_type = shape_type self.canvas.shape_type = shape_type self.canvas.update() def update_shape_size(self, shape_size): self.shape_size = shape_size self.canvas.shape_size = shape_size self.canvas.update() class ShapeCanvas(QWidget): def __init__(self): super().__init__() self.shape_type = "Circle" self.shape_size = 100 def paintEvent(self, event): painter = QPainter(self) painter.setRenderHint(painter.RenderHint.Antialiasing) if self.shape_type == "Circle": painter.setPen(QPen(Qt.GlobalColor.black, 2)) painter.setBrush(QBrush(Qt.GlobalColor.white)) painter.drawEllipse(50, 50, self.shape_size, self.shape_size) elif self.shape_type == "Rectangle": painter.setPen(QPen(Qt.GlobalColor.black, 2)) painter.setBrush(QBrush(Qt.GlobalColor.white)) painter.drawRect(50, 50, self.shape_size, self.shape_size) elif self.shape_type == "Triangle": painter.setPen(QPen(Qt.GlobalColor.black, 2)) painter.setBrush(QBrush(Qt.GlobalColor.white)) x = 50 + self.shape_size / 2 y = 50 points = [x, y + self.shape_size, 50, 50 + self.shape_size, 50 + self.shape_size, 50 + self.shape_size] painter.drawPolygon(*points) if __name__ == "__main__": app = QApplication(sys.argv) shape_selector = ShapeSelector() shape_selector.resize(600, 400) shape_selector.show() sys.exit(app.exec()) ``` This code defines a custom widget called `ShapeSelector` that includes a drop-down menu for selecting the shape type, a slider for adjusting the shape's size, and a canvas for rendering the selected shape. The `update_shape_type` and `update_shape_size` methods are used to update the shape type and size based on the user's input. **Customizing the Looks of the Shapes** We can enhance the app design by adding more styles and customization options for the shapes. For example, we can add a list of colors and allow users to select the shape's fill color. We can also add more shapes and customize their appearance using different brushes and pens. **Extending the ShapeSelector Widget** We can extend the `ShapeSelector` widget by adding more features, such as: * Adding a text box for setting the shape's label or text. * Creating an animation that changes the shape's color or size over time. * Allowing users to select the shape's outline color and width. * Providing options for saving the shape as an image or exporting it to a vector file format. By leveraging these advanced techniques, you can create more complex and visually appealing custom widgets, enhancing the overall user experience and design of your applications.