The QMainWindow class provides a main application window.| doc.qt.io
The QDialog class is the base class of dialog windows.| doc.qt.io
An overview of the drag and drop system provided by Qt.| doc.qt.io
The QPushButton widget provides a command button.| doc.qt.io
The QPaintDevice class is the base class of objects that can be painted on with QPainter.| doc.qt.io
The QLabel widget provides a text or image display.| doc.qt.io
The QWidget class is the base class of all user interface objects.| doc.qt.io
The QEvent class is the base class of all event classes. Event objects contain event parameters.| doc.qt.io
The Qt namespace contains miscellaneous identifiers used throughout the Qt library.| doc.qt.io
The QPainter class performs low-level painting on widgets and other paint devices.| doc.qt.io