A custom QWidget that displays a vertical bar with colored segments (dial-like) using QPainter. It emits a valueChanged signal when the user clicks/drags, and supports setting colors, bar count, and steps. The widget is self-contained, imports only Qt modules, and can be dropped into any PyQt6/PySide6 project as a power meter or level indicator. Demonstrates custom painting and signal-slot architecture.

An animated toggle switch widget that inherits QAbstractButton. It uses a QPropertyAnimation for smooth sliding and color transitions. Supports state toggling with mouse clicks and emits toggled signal. The widget is purely paint-based (no images) and can be reused as a modern toggle button in any Qt application. Demonstrates property animation and custom painting.

A custom password input field that extends QLineEdit with a toggleable visibility button (eye icon). Users can show/hide the password by clicking the embedded button. The widget uses a QAction to add the button to the line edit's trailing position. It is self-contained, imports only Qt modules and SVG icons, and can be reused in any login form. Demonstrates line edit customization and action-based button placement.

A custom range slider widget that provides two handles (minimum and maximum) on a horizontal slider. Users can drag either handle to select a numeric range. It emits a rangeChanged signal with min/max values. The widget handles handle collision and boundary enforcement. It is self-contained and can be reused as a range selector in filtering UIs or any application requiring a numeric range input.

Demonstrates the QRunnable + QThreadPool pattern for offloading background tasks without freezing the UI. The Worker class is defined with a WorkerSignals QObject that emits finished, progress, and error signals. This pattern is reused across many demos (weather, crypto, unzip) and can be extracted as a reusable async task runner for any Qt application. Example_003 shows a long-running task with progress reporting.