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<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
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<!-- qevent.cpp -->
  <title>Qt 4.8: QHoverEvent Class Reference</title>
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    <a href="index.html" class="qtref"><span>Qt Reference Documentation</span></a>
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<div class="toc">
<h3><a name="toc">Contents</a></h3>
<ul>
<li class="level1"><a href="#public-functions">Public Functions</a></li>
<li class="level1"><a href="#details">Detailed Description</a></li>
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<h1 class="title">QHoverEvent Class Reference</h1>
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<p>The QHoverEvent class contains parameters that describe a mouse event. <a href="#details">More...</a></p>
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<pre class="cpp"> <span class="preprocessor">#include &lt;QHoverEvent&gt;</span></pre><p><b>Inherits: </b><a href="qevent.html">QEvent</a>.</p>
<ul>
<li><a href="qhoverevent-members.html">List of all members, including inherited members</a></li>
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<a name="public-functions"></a>
<h2>Public Functions</h2>
<table class="alignedsummary">
<tr><td class="memItemLeft rightAlign topAlign"> </td><td class="memItemRight bottomAlign"><b><a href="qhoverevent.html#QHoverEvent">QHoverEvent</a></b> ( Type <i>type</i>, const QPoint &amp; <i>pos</i>, const QPoint &amp; <i>oldPos</i> )</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> const QPoint &amp; </td><td class="memItemRight bottomAlign"><b><a href="qhoverevent.html#oldPos">oldPos</a></b> () const</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> const QPoint &amp; </td><td class="memItemRight bottomAlign"><b><a href="qhoverevent.html#pos">pos</a></b> () const</td></tr>
</table>
<ul>
<li class="fn">6 public functions inherited from <a href="qevent.html#public-functions">QEvent</a></li>
</ul>
<h3>Additional Inherited Members</h3>
<ul>
<li class="fn">1 property inherited from <a href="qevent.html#properties">QEvent</a></li>
<li class="fn">1 static public member inherited from <a href="qevent.html#static-public-members">QEvent</a></li>
</ul>
<a name="details"></a>
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<div class="descr">
<h2>Detailed Description</h2>
<p>The QHoverEvent class contains parameters that describe a mouse event.</p>
<p>Mouse events occur when a mouse cursor is moved into, out of, or within a widget, and if the widget has the <a href="qt.html#WidgetAttribute-enum">Qt::WA_Hover</a> attribute.</p>
<p>The function <a href="qhoverevent.html#pos">pos</a>() gives the current cursor position, while <a href="qhoverevent.html#oldPos">oldPos</a>() gives the old mouse position.</p>
<p>There are a few similarities between the events <a href="qevent.html#Type-enum">QEvent::HoverEnter</a> and <a href="qevent.html#Type-enum">QEvent::HoverLeave</a>, and the events <a href="qevent.html#Type-enum">QEvent::Enter</a> and <a href="qevent.html#Type-enum">QEvent::Leave</a>. However, they are slightly different because we do an update() in the event handler of <a href="qevent.html#Type-enum">HoverEnter</a> and <a href="qevent.html#Type-enum">HoverLeave</a>.</p>
<p><a href="qevent.html#Type-enum">QEvent::HoverMove</a> is also slightly different from <a href="qevent.html#Type-enum">QEvent::MouseMove</a>. Let us consider a top-level window A containing a child B which in turn contains a child C (all with mouse tracking enabled):</p>
<p class="centerAlign"><img src="images/hoverevents.png" alt="" /></p><p>Now, if you move the cursor from the top to the bottom in the middle of A, you will get the following <a href="qevent.html#Type-enum">QEvent::MouseMove</a> events:</p>
<ol class="1">
<li>A::MouseMove</li>
<li>B::MouseMove</li>
<li>C::MouseMove</li>
</ol>
<p>You will get the same events for <a href="qevent.html#Type-enum">QEvent::HoverMove</a>, except that the event always propagates to the top-level regardless whether the event is accepted or not. It will only stop propagating with the <a href="qt.html#WidgetAttribute-enum">Qt::WA_NoMousePropagation</a> attribute.</p>
<p>In this case the events will occur in the following way:</p>
<ol class="1">
<li>A::HoverMove</li>
<li>A::HoverMove, B::HoverMove</li>
<li>A::HoverMove, B::HoverMove, C::HoverMove</li>
</ol>
</div>
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<div class="func">
<h2>Member Function Documentation</h2>
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<h3 class="fn"><a name="QHoverEvent"></a>QHoverEvent::<span class="name">QHoverEvent</span> ( <span class="type"><a href="qevent.html#Type-enum">Type</a></span> <i>type</i>, const <span class="type"><a href="qpoint.html">QPoint</a></span> &amp; <i>pos</i>, const <span class="type"><a href="qpoint.html">QPoint</a></span> &amp; <i>oldPos</i> )</h3>
<p>Constructs a hover event object.</p>
<p>The <i>type</i> parameter must be <a href="qevent.html#Type-enum">QEvent::HoverEnter</a>, <a href="qevent.html#Type-enum">QEvent::HoverLeave</a>, or <a href="qevent.html#Type-enum">QEvent::HoverMove</a>.</p>
<p>The <i>pos</i> is the current mouse cursor's position relative to the receiving widget, while <i>oldPos</i> is the previous mouse cursor's position relative to the receiving widget.</p>
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<h3 class="fn"><a name="oldPos"></a>const <span class="type"><a href="qpoint.html">QPoint</a></span> &amp; QHoverEvent::<span class="name">oldPos</span> () const</h3>
<p>Returns the previous position of the mouse cursor, relative to the widget that received the event. If there is no previous position, oldPos() will return the same position as <a href="qhoverevent.html#pos">pos</a>().</p>
<p>On <a href="qevent.html#Type-enum">QEvent::HoverEnter</a> events, this position will always be <a href="qpoint.html">QPoint</a>(-1, -1).</p>
<p><b>See also </b><a href="qhoverevent.html#pos">pos</a>().</p>
<!-- @@@oldPos -->
<!-- $$$pos[overload1]$$$pos -->
<h3 class="fn"><a name="pos"></a>const <span class="type"><a href="qpoint.html">QPoint</a></span> &amp; QHoverEvent::<span class="name">pos</span> () const</h3>
<p>Returns the position of the mouse cursor, relative to the widget that received the event.</p>
<p>On <a href="qevent.html#Type-enum">QEvent::HoverLeave</a> events, this position will always be <a href="qpoint.html">QPoint</a>(-1, -1).</p>
<p><b>See also </b><a href="qhoverevent.html#oldPos">oldPos</a>().</p>
<!-- @@@pos -->
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