Qt

Qt project structure (qmake `.pro`/`.pri`/`.prf`/`.prl`, CMake), the code generators (`moc`, `uic`, `rcc`, `lrelease`), build with `qmake`/`cmake`, the app-icon and resource pipeline, dynamic vs static linking, and deployment with `windeployqt`/`macdeployqt`

The Qt Widgets module — `QWidget` lifecycle and geometry, dialogs (modal/modeless, file/input/message/progress/error/wizard), display widgets (label, LCD, stacked, toolbox), input widgets (button family, line edit, combo, spin/date), sliders, and rich-text editors

Qt layout managers (`QHBoxLayout`/`QVBoxLayout`/`QGridLayout`/`QFormLayout`/`QStackedLayout`), `QSplitter`, size policy and stretch, `QMainWindow` (menus, toolbars, dock widgets, status bar), `QAction`, palette and transparency, buddy and tab order

How Qt's signal/slot mechanism works — `Q_OBJECT` and `moc`, the modern functor `connect` syntax vs the legacy `SIGNAL/SLOT` macros, connection types (direct, queued, blocking-queued, auto), the Meta-Object System (`qobject_cast`, `tr`, `Q_PROPERTY`, `Q_INVOKABLE`)

How Qt delivers input and system events — `QEvent` hierarchy, virtual handler overrides (`keyPressEvent`, `mousePressEvent`, `wheelEvent`, `dragEnterEvent`, `dropEvent`, `paintEvent`, `resizeEvent`, `closeEvent`), `accept`/`ignore` propagation, event filters (`installEventFilter`, `eventFilter`), `QTimer` / `QTimerEvent`, and custom events

2D drawing with `QPainter` on `QPaintDevice` (`QWidget`/`QImage`/`QPixmap`/`QPicture`), coordinate transforms, composition modes, `update` vs `repaint`, the `QImage`/`QPixmap`/`QBitmap` family, the Graphics View Framework (`QGraphicsScene`/`QGraphicsView`/`QGraphicsItem`), and OpenGL integration via `QOpenGLWidget`

Qt's container family (`QList`/`QVector`/`QHash`/`QMap`/`QSet`/`QStack`/`QQueue`), implicit sharing (COW), STL interop, `QString` and `QByteArray`, `QVariant`, and the i18n pipeline (`tr` + `lupdate` + Qt Linguist + `QTranslator`)