Question

These classes are normally-heavy classes which in Qt have been optimized by the use of reference counter and common data so they can be passed around.

The only important effect is that the classes listed here can be passed around as arguments efficiently, even though they may seem heavyweight.

QBitArray	Array of bits
QBitmap	Monochrome (1-bit depth) pixmaps
QBrush	Defines the fill pattern of shapes drawn by a QPainter
QCString	Abstraction of the classic C zero-terminated char array (char *)
QCursor	Mouse cursor with an arbitrary shape
QFont	Font used for drawing text
QFontInfo	General information about fonts
QFontMetrics	Font metrics information
QIconSet	Set of icons with different styles and sizes
QImage	Hardware-independent pixmap representation with direct access to the pixel data
QMap	Value-based template class that provides a dictionary
QPair	Value-based template class that provides a pair of elements
QPalette	Color groups for each widget state
QPen	Defines how a QPainter should draw lines and outlines of shapes
QPicture	Paint device that records and replays QPainter commands
QPixmap	Off-screen, pixel-based paint device
QPointArray	Array of points
QRegExp	Pattern matching using regular expressions
QString	Abstraction of Unicode text and the classic C null-terminated char array
QStringList	List of strings
QValueList	Value-based template class that provides doubly linked lists
QValueStack	Value-based template class that provides a stack
QValueVector	Value-based template class that provides a dynamic array