Classes - Annotated - Tree - Functions - Home - Structure

QPaintEvent Class Reference

The QPaintEvent class contains event parameters for paint events. More...

#include <qevent.h>

Inherits QEvent.

List of all member functions.

Public Members


Detailed Description

The QPaintEvent class contains event parameters for paint events.

Paint events are sent to widgets that need to update themselves, for instance when part of a widget is exposed because an overlying widget is moved.

The event contains a region() that needs to be updated, and a rect() that is the bounding rectangle of that region. Both are provided because many widgets can't make much use of region(), and rect() can be much faster than region().boundingRect(). Painting is clipped to region() during processing of a paint event.

The erased() function returns TRUE if the region() has been cleared to the widget's background (see QWidget::backgroundMode()), and FALSE if the region's contents are arbitrary.

See also QPainter, QWidget::update(), QWidget::repaint(), QWidget::paintEvent(), QWidget::backgroundMode and QRegion.


Member Function Documentation

QPaintEvent::QPaintEvent ( const QRegion & paintRegion, bool erased = TRUE )

Constructs a paint event object with the region that should be updated.

QPaintEvent::QPaintEvent ( const QRect & paintRect, bool erased = TRUE )

Constructs a paint event object with the rectangle that should be updated.

bool QPaintEvent::erased () const

Returns whether the paint event region (or rectangle) has been erased with the widget's background.

const QRect & QPaintEvent::rect () const

Returns the rectangle that should be updated.

See also region() and QPainter::setClipRect().

Examples: life/life.cpp, qfd/fontdisplayer.cpp, t10/cannon.cpp, t11/cannon.cpp and tooltip/tooltip.cpp.

const QRegion & QPaintEvent::region () const

Returns the region that should be updated.

See also rect() and QPainter::setClipRegion().

Examples: qfd/fontdisplayer.cpp and scribble/scribble.cpp.


Search the documentation, FAQ, qt-interest archive and more (uses www.trolltech.com):


This file is part of the Qt toolkit, copyright © 1995-2001 Trolltech, all rights reserved.


Copyright © 2001 TrolltechTrademarks
Qt version 3.0.0-beta1-beta1