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    <title>Qt 4.0: QIcon Class Reference</title>
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<td align="right" valign="top" width="230"><img src="images/trolltech-logo.png" align="right" width="203" height="32" border="0" /></td></tr></table><h1 align="center">QIcon Class Reference</h1>
<p>The QIcon class provides scalable icons in different modes and states. <a href="#details">More...</a></p>
<pre>#include &lt;QIcon&gt;</pre><p>Part of the <a href="qtgui.html">QtGui</a> module.</p>
<ul>
<li><a href="qicon-members.html">List of all members, including inherited members</a></li>
<li><a href="qicon-qt3.html">Qt 3 support members</a></li>
</ul>
<a name="public-types"></a>
<h3>Public Types</h3>
<ul>
<li><div class="fn"/>enum <b><a href="qicon.html#Mode-enum">Mode</a></b> { Normal, Disabled, Active }</li>
<li><div class="fn"/>enum <b><a href="qicon.html#State-enum">State</a></b> { Off, On }</li>
</ul>
<a name="public-functions"></a>
<h3>Public Functions</h3>
<ul>
<li><div class="fn"/><b><a href="qicon.html#QIcon">QIcon</a></b> ()</li>
<li><div class="fn"/><b><a href="qicon.html#QIcon-2">QIcon</a></b> ( const QPixmap &amp; <i>pixmap</i> )</li>
<li><div class="fn"/><b><a href="qicon.html#QIcon-3">QIcon</a></b> ( const QIcon &amp; <i>other</i> )</li>
<li><div class="fn"/><b><a href="qicon.html#QIcon-4">QIcon</a></b> ( const QString &amp; <i>fileName</i> )</li>
<li><div class="fn"/><b><a href="qicon.html#QIcon-5">QIcon</a></b> ( QIconEngine * <i>engine</i> )</li>
<li><div class="fn"/><b><a href="qicon.html#dtor.QIcon">~QIcon</a></b> ()</li>
<li><div class="fn"/>QSize <b><a href="qicon.html#actualSize">actualSize</a></b> ( const QSize &amp; <i>size</i>, Mode <i>mode</i> = Normal, State <i>state</i> = Off ) const</li>
<li><div class="fn"/>void <b><a href="qicon.html#addFile">addFile</a></b> ( const QString &amp; <i>fileName</i>, const QSize &amp; <i>size</i> = QSize(), Mode <i>mode</i> = Normal, State <i>state</i> = Off )</li>
<li><div class="fn"/>void <b><a href="qicon.html#addPixmap">addPixmap</a></b> ( const QPixmap &amp; <i>pixmap</i>, Mode <i>mode</i> = Normal, State <i>state</i> = Off )</li>
<li><div class="fn"/>bool <b><a href="qicon.html#isNull">isNull</a></b> () const</li>
<li><div class="fn"/>void <b><a href="qicon.html#paint">paint</a></b> ( QPainter * <i>painter</i>, const QRect &amp; <i>rect</i>, Qt::Alignment <i>alignment</i> = Qt::AlignCenter, Mode <i>mode</i> = Normal, State <i>state</i> = Off ) const</li>
<li><div class="fn"/>void <b><a href="qicon.html#paint-2">paint</a></b> ( QPainter * <i>painter</i>, int <i>x</i>, int <i>y</i>, int <i>w</i>, int <i>h</i>, Qt::Alignment <i>alignment</i> = Qt::AlignCenter, Mode <i>mode</i> = Normal, State <i>state</i> = Off ) const</li>
<li><div class="fn"/>QPixmap <b><a href="qicon.html#pixmap">pixmap</a></b> ( const QSize &amp; <i>size</i>, Mode <i>mode</i> = Normal, State <i>state</i> = Off ) const</li>
<li><div class="fn"/>QPixmap <b><a href="qicon.html#pixmap-5">pixmap</a></b> ( int <i>w</i>, int <i>h</i>, Mode <i>mode</i> = Normal, State <i>state</i> = Off ) const</li>
<li><div class="fn"/>QPixmap <b><a href="qicon.html#pixmap-6">pixmap</a></b> ( int <i>extent</i>, Mode <i>mode</i> = Normal, State <i>state</i> = Off ) const</li>
<li><div class="fn"/>int <b><a href="qicon.html#serialNumber">serialNumber</a></b> () const</li>
<li><div class="fn"/><b><a href="qicon.html#operator-QVariant">operator QVariant</a></b> () const</li>
<li><div class="fn"/>QIcon &amp; <b><a href="qicon.html#operator-eq">operator=</a></b> ( const QIcon &amp; <i>other</i> )</li>
</ul>
<a name="details"></a>
<hr />
<h2>Detailed Description</h2>
<p>The QIcon class provides scalable icons in different modes and states.</p>
<p>A QIcon can generate smaller, larger, active, and disabled pixmaps from the set of pixmaps it is given. Such pixmaps are used by Qt widgets to show an icon representing a particular action.</p>
<p>The simplest use of QIcon is to create one from a <a href="qpixmap.html">QPixmap</a> file or resource, and then use it, allowing Qt to work out all the required icon styles and sizes. For example:</p>
<pre>&nbsp;   QToolButton *button = new QToolButton;
    button-&gt;setIcon(QIcon(&quot;open.xpm&quot;));</pre>
<p>When you retrieve a pixmap using pixmap(<a href="qsize.html">QSize</a>, Mode, State), and no pixmap for this given size, mode and state has been added with <a href="qicon.html#addFile">addFile</a>() or <a href="qicon.html#addPixmap">addPixmap</a>(), then QIcon will generate one on the fly. This pixmap generation happens in a <a href="qiconengine.html">QIconEngine</a>. The default engine scales pixmaps down if required, but never up, and it uses the current style to calculate a disabled appearance. By using custom icon engines, you can customize every aspect of generated icons. With <a href="qiconengineplugin.html">QIconEnginePlugin</a> it is possible to register different icon engines for different file suffixes, so you could provide a SVG icon engine or any other scalable format.</p>
<a name="making-classes-that-use-qicon"></a>
<h3>Making Classes that Use QIcon</h3>
<p>If you write your own widgets that have an option to set a small pixmap, consider allowing a QIcon to be set for that pixmap. The Qt class <a href="qtoolbutton.html">QToolButton</a> is an example of such a widget.</p>
<p>Provide a method to set a QIcon, and when you draw the icon, choose whichever pixmap is appropriate for the current state of your widget. For example:</p>
<pre>&nbsp;   void MyWidget::drawIcon(QPainter *painter, QPoint pos)
    {
        QPixmap pixmap = icon.pixmap(QSize(22, 22),
                                       isEnabled() ? QIcon::Normal
                                                   : QIcon::Disabled,
                                       isOn() ? QIcon::On
                                              : QIcon::Off);
        painter-&gt;drawPixmap(pos, pixmap);
    }</pre>
<p>You might also make use of the <tt>Active</tt> mode, perhaps making your widget <tt>Active</tt> when the mouse is over the widget (see <a href="qwidget.html#enterEvent">QWidget::enterEvent</a>()), while the mouse is pressed pending the release that will activate the function, or when it is the currently selected item. If the widget can be toggled, the &quot;On&quot; mode might be used to draw a different icon.</p>
<center><img src="images/icon.png" alt="QIcon" /></center><p>See also <a href="guibooks.html#fowler">GUI Design Handbook: Iconic Label</a>.</p>
<hr />
<h2>Member Type Documentation</h2>
<h3 class="fn"><a name="Mode-enum"></a>enum QIcon::Mode</h3>
<p>This enum type describes the mode for which a pixmap is intended to be used. The currently defined modes are:</p>
<table border="1" cellpadding="2" cellspacing="1" width="100%">
<tr><th width="25%">Constant</th><th width="15%">Value</th><th width="60%">Description</th></tr>
<tr><td valign="top"><tt>QIcon::Normal</tt></td><td align="center" valign="top"><tt>0</tt></td><td valign="top">Display the pixmap when the user is not interacting with the icon, but the functionality represented by the icon is available.</td></tr>
<tr><td valign="top"><tt>QIcon::Disabled</tt></td><td align="center" valign="top"><tt>1</tt></td><td valign="top">Display the pixmap when the functionality represented by the icon is not available.</td></tr>
<tr><td valign="top"><tt>QIcon::Active</tt></td><td align="center" valign="top"><tt>2</tt></td><td valign="top">Display the pixmap when the functionality represented by the icon is available and the user is interacting with the icon, for example, moving the mouse over it or clicking it.</td></tr>
</table>
<h3 class="fn"><a name="State-enum"></a>enum QIcon::State</h3>
<p>This enum describes the state for which a pixmap is intended to be used. The <i>state</i> can be:</p>
<table border="1" cellpadding="2" cellspacing="1" width="100%">
<tr><th width="25%">Constant</th><th width="15%">Value</th><th width="60%">Description</th></tr>
<tr><td valign="top"><tt>QIcon::Off</tt></td><td align="center" valign="top"><tt>1</tt></td><td valign="top">Display the pixmap when the widget is in an &quot;off&quot; state</td></tr>
<tr><td valign="top"><tt>QIcon::On</tt></td><td align="center" valign="top"><tt>0</tt></td><td valign="top">Display the pixmap when the widget is in an &quot;on&quot; state</td></tr>
</table>
<hr />
<h2>Member Function Documentation</h2>
<h3 class="fn"><a name="QIcon"></a>QIcon::QIcon ()</h3>
<p>Constructs a null icon.</p>
<h3 class="fn"><a name="QIcon-2"></a>QIcon::QIcon ( const <a href="qpixmap.html">QPixmap</a> &amp; <i>pixmap</i> )</h3>
<p>Constructs an icon from a <i>pixmap</i>.</p>
<h3 class="fn"><a name="QIcon-3"></a>QIcon::QIcon ( const QIcon &amp; <i>other</i> )</h3>
<p>Constructs a copy of <i>other</i>. This is very fast.</p>
<h3 class="fn"><a name="QIcon-4"></a>QIcon::QIcon ( const <a href="qstring.html">QString</a> &amp; <i>fileName</i> )</h3>
<p>Constructs an icon from the file with the given <i>fileName</i>. The file will be loaded on demand. If the file does not exist or is of an unknown format, the icon becomes a null icon.</p>
<p>If <i>fileName</i> contains a relative path (e.g. the filename only) the relevant file must be found relative to the runtime working directory.</p>
<p>The file name can be either refer to an actual file on disk or to one of the application's embedded resources. See the <a href="resources.html">Resource System</a> overview for details on how to embed images and other resource files in the application's executable.</p>
<h3 class="fn"><a name="QIcon-5"></a>QIcon::QIcon ( <a href="qiconengine.html">QIconEngine</a> * <i>engine</i> )</h3>
<p>Creates an icon with a specific icon <i>engine</i>. The icon takes ownership of the engine.</p>
<h3 class="fn"><a name="dtor.QIcon"></a>QIcon::~QIcon ()</h3>
<p>Destroys the icon.</p>
<h3 class="fn"><a name="actualSize"></a><a href="qsize.html">QSize</a> QIcon::actualSize ( const <a href="qsize.html">QSize</a> &amp; <i>size</i>, <a href="qicon.html#Mode-enum">Mode</a> <i>mode</i> = Normal, <a href="qicon.html#State-enum">State</a> <i>state</i> = Off ) const</h3>
<p>Returns the actual size of the icon for the requested <i>size</i>, <i>mode</i>, and <i>state</i>. The result might be smaller than requested, but never larger.</p>
<p>See also <a href="qicon.html#pixmap">pixmap</a>() and <a href="qicon.html#paint">paint</a>().</p>
<h3 class="fn"><a name="addFile"></a>void QIcon::addFile ( const <a href="qstring.html">QString</a> &amp; <i>fileName</i>, const <a href="qsize.html">QSize</a> &amp; <i>size</i> = QSize(), <a href="qicon.html#Mode-enum">Mode</a> <i>mode</i> = Normal, <a href="qicon.html#State-enum">State</a> <i>state</i> = Off )</h3>
<p>Adds a pixmap from the file with the given <i>fileName</i> to the icon, as a specialization for <i>size</i>, <i>mode</i> and <i>state</i>. The file will be loaded on demand. Note: custom icon engines are free to ignore additionally added pixmaps.</p>
<p>If <i>fileName</i> contains a relative path (e.g. the filename only) the relevant file must be found relative to the runtime working directory.</p>
<p>The file name can be either refer to an actual file on disk or to one of the application's embedded resources. See the <a href="resources.html">Resource System</a> overview for details on how to embed images and other resource files in the application's executable.</p>
<p>See also <a href="qicon.html#addPixmap">addPixmap</a>().</p>
<h3 class="fn"><a name="addPixmap"></a>void QIcon::addPixmap ( const <a href="qpixmap.html">QPixmap</a> &amp; <i>pixmap</i>, <a href="qicon.html#Mode-enum">Mode</a> <i>mode</i> = Normal, <a href="qicon.html#State-enum">State</a> <i>state</i> = Off )</h3>
<p>Adds <i>pixmap</i> to the icon, as a specialization for <i>mode</i> and <i>state</i>.</p>
<p>Custom icon engines are free to ignore additionally added pixmaps.</p>
<p>See also <a href="qicon.html#addFile">addFile</a>().</p>
<h3 class="fn"><a name="isNull"></a>bool QIcon::isNull () const</h3>
<p>Returns true if the icon is empty; otherwise returns false.</p>
<h3 class="fn"><a name="paint"></a>void QIcon::paint ( <a href="qpainter.html">QPainter</a> * <i>painter</i>, const <a href="qrect.html">QRect</a> &amp; <i>rect</i>, <a href="qt.html#AlignmentFlag-enum">Qt::Alignment</a> <i>alignment</i> = Qt::AlignCenter, <a href="qicon.html#Mode-enum">Mode</a> <i>mode</i> = Normal, <a href="qicon.html#State-enum">State</a> <i>state</i> = Off ) const</h3>
<p>Uses the <i>painter</i> to paint the icon with specified <i>alignment</i>, required <i>mode</i>, and <i>state</i> into the rectangle <i>rect</i>.</p>
<p>See also <a href="qicon.html#actualSize">actualSize</a>() and <a href="qicon.html#pixmap">pixmap</a>().</p>
<h3 class="fn"><a name="paint-2"></a>void QIcon::paint ( <a href="qpainter.html">QPainter</a> * <i>painter</i>, int <i>x</i>, int <i>y</i>, int <i>w</i>, int <i>h</i>, <a href="qt.html#AlignmentFlag-enum">Qt::Alignment</a> <i>alignment</i> = Qt::AlignCenter, <a href="qicon.html#Mode-enum">Mode</a> <i>mode</i> = Normal, <a href="qicon.html#State-enum">State</a> <i>state</i> = Off ) const</h3>
<p>This is an overloaded member function, provided for convenience. It behaves essentially like the above function.</p>
<p>Paints the icon into the rectangle <a href="qrect.html">QRect</a>(<i>x</i>, <i>y</i>, <i>w</i>, <i>h</i>).</p>
<h3 class="fn"><a name="pixmap"></a><a href="qpixmap.html">QPixmap</a> QIcon::pixmap ( const <a href="qsize.html">QSize</a> &amp; <i>size</i>, <a href="qicon.html#Mode-enum">Mode</a> <i>mode</i> = Normal, <a href="qicon.html#State-enum">State</a> <i>state</i> = Off ) const</h3>
<p>Returns a pixmap with the requested <i>size</i>, <i>mode</i>, and <i>state</i>, generating one if necessary. The pixmap might be smaller than requested, but never larger.</p>
<p>See also <a href="qicon.html#actualSize">actualSize</a>() and <a href="qicon.html#paint">paint</a>().</p>
<h3 class="fn"><a name="pixmap-5"></a><a href="qpixmap.html">QPixmap</a> QIcon::pixmap ( int <i>w</i>, int <i>h</i>, <a href="qicon.html#Mode-enum">Mode</a> <i>mode</i> = Normal, <a href="qicon.html#State-enum">State</a> <i>state</i> = Off ) const</h3>
<p>This is an overloaded member function, provided for convenience. It behaves essentially like the above function.</p>
<p>Returns a pixmap of size <a href="qsize.html">QSize</a>(<i>w</i>, <i>h</i>).</p>
<h3 class="fn"><a name="pixmap-6"></a><a href="qpixmap.html">QPixmap</a> QIcon::pixmap ( int <i>extent</i>, <a href="qicon.html#Mode-enum">Mode</a> <i>mode</i> = Normal, <a href="qicon.html#State-enum">State</a> <i>state</i> = Off ) const</h3>
<p>This is an overloaded member function, provided for convenience. It behaves essentially like the above function.</p>
<p>Returns a pixmap of size <a href="qsize.html">QSize</a>(<i>extent</i>, <i>extent</i>).</p>
<h3 class="fn"><a name="serialNumber"></a>int QIcon::serialNumber () const</h3>
<p>Returns a number that uniquely identifies the contents of this <a href="qicon.html">QIcon</a> object. This means that multiple <a href="qicon.html">QIcon</a> objects can have the same serial number as long as they refer to the same contents.</p>
<p>A null icon always has a serial number of 0.</p>
<p>See also <a href="qpixmap.html#serialNumber">QPixmap::serialNumber</a>().</p>
<h3 class="fn"><a name="operator-QVariant"></a>QIcon::operator QVariant () const</h3>
<p>Returns the icon as a <a href="qvariant.html">QVariant</a>.</p>
<h3 class="fn"><a name="operator-eq"></a>QIcon &amp; QIcon::operator= ( const QIcon &amp; <i>other</i> )</h3>
<p>Assigns the <i>other</i> icon to this icon and returns a reference to this icon.</p>
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