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 a covering
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, QRegion and Event Classes.
Member Function Documentation
QPaintEvent::QPaintEvent ( const QRegion & paintRegion, bool erased = TRUE )
Constructs a paint event object with the region that should be
updated. The region is given by paintRegion. If erased is
TRUE the region will be cleared before repainting.
QPaintEvent::QPaintEvent ( const QRect & paintRect, bool erased = TRUE )
Constructs a paint event object with the rectangle that should be
updated. The region is given by paintRect. If erased is TRUE
the region will be cleared before repainting.
bool QPaintEvent::erased () const
Returns TRUE if the paint event region (or rectangle) has been
erased with the widget's background; otherwise returns FALSE.
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, showimg/showimg.cpp, t10/cannon.cpp, t11/cannon.cpp, t13/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.
This file is part of the Qt toolkit.
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