The QPaintDevice class is the base class of objects that can be painted on with QPainter.| doc.qt.io
The QSizeF class defines the size of a two-dimensional object using floating point precision.| doc.qt.io
The QAbstractTextDocumentLayout class is an abstract base class used to implement custom layouts for QTextDocuments.| doc.qt.io
The QObject class is the base class of all Qt objects.| 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
The QTextDocument class holds formatted text.| doc.qt.io
The QString class provides a Unicode character string.| doc.qt.io