<?xml version="1.0" encoding="iso-8859-1"?>
<!DOCTYPE html
PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<!-- /tmp/qt-4.2.1-harald-1161357942206/qt-x11-opensource-src-4.2.1/src/gui/kernel/qevent.cpp -->
<head>
<title>Qt 4.2: QPaintEvent Class Reference</title>
<link href="classic.css" rel="stylesheet" type="text/css" />
</head>
<body>
<table border="0" cellpadding="0" cellspacing="0" width="100%">
<tr>
<td align="left" valign="top" width="32"><a href="http://www.trolltech.com/products/qt"><img src="images/qt-logo.png" align="left" width="32" height="32" border="0" /></a></td>
<td width="1"> </td><td class="postheader" valign="center"><a href="index.html"><font color="#004faf">Home</font></a> · <a href="classes.html"><font color="#004faf">All Classes</font></a> · <a href="mainclasses.html"><font color="#004faf">Main Classes</font></a> · <a href="groups.html"><font color="#004faf">Grouped Classes</font></a> · <a href="modules.html"><font color="#004faf">Modules</font></a> · <a href="functions.html"><font color="#004faf">Functions</font></a></td>
<td align="right" valign="top" width="230"><a href="http://www.trolltech.com"><img src="images/trolltech-logo.png" align="right" width="203" height="32" border="0" /></a></td></tr></table><h1 align="center">QPaintEvent Class Reference<br /><sup><sup>[<a href="qtgui.html">QtGui</a> module]</sup></sup></h1>
<p>The QPaintEvent class contains event parameters for paint events. <a href="#details">More...</a></p>
<pre> #include <QPaintEvent></pre><p>Inherits <a href="qevent.html">QEvent</a>.</p>
<ul>
<li><a href="qpaintevent-members.html">List of all members, including inherited members</a></li>
<li><a href="qpaintevent-qt3.html">Qt 3 support members</a></li>
</ul>
<a name="public-functions"></a>
<h3>Public Functions</h3>
<ul>
<li><div class="fn"/><b><a href="qpaintevent.html#QPaintEvent">QPaintEvent</a></b> ( const QRegion & <i>paintRegion</i> )</li>
<li><div class="fn"/><b><a href="qpaintevent.html#QPaintEvent-2">QPaintEvent</a></b> ( const QRect & <i>paintRect</i> )</li>
<li><div class="fn"/>const QRect & <b><a href="qpaintevent.html#rect">rect</a></b> () const</li>
<li><div class="fn"/>const QRegion & <b><a href="qpaintevent.html#region">region</a></b> () const</li>
</ul>
<ul>
<li><div class="fn"/>6 public functions inherited from <a href="qevent.html#public-functions">QEvent</a></li>
</ul>
<h3>Additional Inherited Members</h3>
<ul>
<li><div class="fn"/>1 property inherited from <a href="qevent.html#properties">QEvent</a></li>
</ul>
<a name="details"></a>
<hr />
<h2>Detailed Description</h2>
<p>The QPaintEvent class contains event parameters for paint events.</p>
<p>Paint events are sent to widgets that need to update themselves, for instance when part of a widget is exposed because a covering widget was moved.</p>
<p>The event contains a <a href="qpaintevent.html#region">region</a>() that needs to be updated, and a <a href="qpaintevent.html#rect">rect</a>() that is the bounding rectangle of that region. Both are provided because many widgets can't make much use of <a href="qpaintevent.html#region">region</a>(), and <a href="qpaintevent.html#rect">rect</a>() can be much faster than <a href="qpaintevent.html#region">region</a>().boundingRect(). Painting is clipped to <a href="qpaintevent.html#region">region</a>() during the processing of a paint event.</p>
<p>See also <a href="qpainter.html">QPainter</a>, <a href="qwidget.html#update">QWidget::update</a>(), <a href="qwidget.html#repaint">QWidget::repaint</a>(), and <a href="qwidget.html#paintEvent">QWidget::paintEvent</a>().</p>
<hr />
<h2>Member Function Documentation</h2>
<h3 class="fn"><a name="QPaintEvent"></a>QPaintEvent::QPaintEvent ( const <a href="qregion.html">QRegion</a> & <i>paintRegion</i> )</h3>
<p>Constructs a paint event object with the region that needs to be updated. The region is specified by <i>paintRegion</i>.</p>
<h3 class="fn"><a name="QPaintEvent-2"></a>QPaintEvent::QPaintEvent ( const <a href="qrect.html">QRect</a> & <i>paintRect</i> )</h3>
<p>Constructs a paint event object with the rectangle that needs to be updated. The region is specified by <i>paintRect</i>.</p>
<h3 class="fn"><a name="rect"></a>const <a href="qrect.html">QRect</a> & QPaintEvent::rect () const</h3>
<p>Returns the rectangle that needs to be updated.</p>
<p>See also <a href="qpaintevent.html#region">region</a>() and <a href="qpainter.html#setClipRect">QPainter::setClipRect</a>().</p>
<h3 class="fn"><a name="region"></a>const <a href="qregion.html">QRegion</a> & QPaintEvent::region () const</h3>
<p>Returns the region that needs to be updated.</p>
<p>See also <a href="qpaintevent.html#rect">rect</a>() and <a href="qpainter.html#setClipRegion">QPainter::setClipRegion</a>().</p>
<hr />
<h2>Member Function Documentation</h2>
<h3 class="fn"><a name="QPaintEvent-3"></a>QPaintEvent::QPaintEvent ( const <a href="qregion.html">QRegion</a> & <i>paintRegion</i>, const <a href="qrect.html">QRect</a> & <i>paintRect</i> )</h3>
<p>Constructs a paint event object with both a <i>paintRegion</i> and a <i>paintRect</i>, both of which represent the area of the widget that needs to be updated.</p>
<h3 class="fn"><a name="erased"></a>bool QPaintEvent::erased () const</h3>
<p>Returns true if the paint event region (or rectangle) has been erased with the widget's background; otherwise returns false.</p>
<p>Qt 4 <i>always</i> erases regions that require painting. The exception to this rule is if the widget sets the <a href="qt.html#WidgetAttribute-enum">Qt::WA_OpaquePaintEvent</a> or <a href="qt.html#WidgetAttribute-enum">Qt::WA_NoSystemBackground</a> attributes. If either one of those attributes is set <i>and</i> the window system does not make use of subwidget alpha composition (currently X11 and Windows, but this may change), then the region is not erased.</p>
<p /><address><hr /><div align="center">
<table width="100%" cellspacing="0" border="0"><tr class="address">
<td width="30%">Copyright © 2006 <a href="trolltech.html">Trolltech</a></td>
<td width="40%" align="center"><a href="trademarks.html">Trademarks</a></td>
<td width="30%" align="right"><div align="right">Qt 4.2.1</div></td>
</tr></table></div></address></body>
</html>
