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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"><!-- /home/reggie/tmp/qt-3.0-reggie-5401/qt-x11-commercial-3.0.5/src/kernel/qdesktopwidget_win.cpp:174 --><html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>QDesktopWidget Class</title><style type="text/css"><!--h3.fn,span.fn { margin-left: 1cm; text-indent: -1cm; }a:link { color: #004faf; text-decoration: none }a:visited { color: #672967; text-decoration: none }body { background: #ffffff; color: black; }--></style></head><body><table border="0" cellpadding="0" cellspacing="0" width="100%"><tr bgcolor="#E5E5E5"><td 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="annotated.html"><font color="#004faf">Annotated</font></a> | <a href="groups.html"><font color="#004faf">Grouped Classes</font></a> | <a href="functions.html"><font color="#004faf">Functions</font></a></td><td align="right" valign="center"><img src="logo32.png" align="right" width="64" height="32" border="0"></td></tr></table><h1 align=center>QDesktopWidget Class Reference</h1><p>The QDesktopWidget class provides access to screen information on multi-head systems.<a href="#details">More...</a><p><tt>#include <<a href="qdesktopwidget-h.html">qdesktopwidget.h</a>></tt><p>Inherits <a href="qwidget.html">QWidget</a>.<p><a href="qdesktopwidget-members.html">List of all member functions.</a><h2>Public Members</h2><ul><li><div class=fn><a href="#QDesktopWidget"><b>QDesktopWidget</b></a> ()</div></li><li><div class=fn><a href="#~QDesktopWidget"><b>~QDesktopWidget</b></a> ()</div></li><li><div class=fn>bool <a href="#isVirtualDesktop"><b>isVirtualDesktop</b></a> () const</div></li><li><div class=fn>int <a href="#numScreens"><b>numScreens</b></a> () const</div></li><li><div class=fn>int <a href="#primaryScreen"><b>primaryScreen</b></a> () const</div></li><li><div class=fn>int <a href="#screenNumber"><b>screenNumber</b></a> ( QWidget * widget = 0 ) const</div></li><li><div class=fn>int <a href="#screenNumber-2"><b>screenNumber</b></a> ( const QPoint & point ) const</div></li><li><div class=fn>QWidget * <a href="#screen"><b>screen</b></a> ( int screen = -1 )</div></li><li><div class=fn>const QRect & <a href="#screenGeometry"><b>screenGeometry</b></a> ( int screen = -1 ) const</div></li></ul><hr><a name="details"></a><h2>Detailed Description</h2>The QDesktopWidget class provides access to screen information on multi-head systems.<p> <p> Systems with more than one graphics card and monitor can manage thephysical screen space available either as multiple desktops, or as alarge virtual desktop, which usually has the size of the boundingrectangle of all the screens (see <a href="#isVirtualDesktop">isVirtualDesktop</a>()). For anapplication, one of the available screens is the primary screen, i.e.the screen where the main widget resides (see <a href="#primaryScreen">primaryScreen</a>()). Allwindows opened in the context of the application must beconstrained to the boundaries of the primary screen; for example,it would be inconvenient if a dialog box popped up on a differentscreen, or split over two screens.<p> The QDesktopWidget provides information about the geometry of theavailable screens with <a href="#screenGeometry">screenGeometry</a>(). The number of screensavailable is returned by <a href="#numScreens">numScreens</a>(). The screen number that aparticular point or widget is located in is returned by<a href="#screenNumber">screenNumber</a>().<p> Widgets provided by Qt use this class, for example, to placetooltips, menus and dialog boxes according to the parent orapplication widget.<p> Applications can use this class to save window positions, or to placechild widgets on one screen.<p> <center><img src="qdesktopwidget.png" alt="Managing Multiple Screens"></center> <p> In the illustration above, Application One's primary screen isscreen 0, and App Two's primary screen is screen 1.<p>See also <a href="advanced.html">Advanced Widgets</a> and <a href="environment.html">Environment Classes</a>.<hr><h2>Member Function Documentation</h2><h3 class=fn><a name="QDesktopWidget"></a>QDesktopWidget::QDesktopWidget ()</h3>Creates the desktop widget.<p> If the system supports a virtual desktop, this widget will havethe size of the virtual desktop; otherwise this widget will havethe size of the primary screen.<p> Instead of using QDesktopWidget directly, useQAppliation::desktop().<h3 class=fn><a name="~QDesktopWidget"></a>QDesktopWidget::~QDesktopWidget ()</h3>Destroy the object and free allocated resources.<h3 class=fn>bool <a name="isVirtualDesktop"></a>QDesktopWidget::isVirtualDesktop () const</h3>Returns TRUE if the system manages the available screens in avirtual desktop; otherwise returns FALSE.<p> For virtual desktops, <a href="#screen">screen</a>() will always return the same widget.The size of the virtual desktop is the size of this desktopwidget.<h3 class=fn>int <a name="numScreens"></a>QDesktopWidget::numScreens () const</h3>Returns the number of available screens.<p> <p>See also <a href="#primaryScreen">primaryScreen</a>().<h3 class=fn>int <a name="primaryScreen"></a>QDesktopWidget::primaryScreen () const</h3>Returns the index of the primary screen.<p> <p>See also <a href="#numScreens">numScreens</a>().<h3 class=fn><a href="qwidget.html">QWidget</a> * <a name="screen"></a>QDesktopWidget::screen ( int screen = -1 )</h3>Returns a widget that represents the screen with index <em>screen</em>.This widget can be used to draw directly on the desktop, using anunclipped painter like this:<p> <pre> <a href="qpainter.html">QPainter</a> paint( QApplication::<a href="qapplication.html#desktop">desktop</a>()->screen( 0 ), TRUE ); paint.draw... ... paint.<a href="qpainter.html#end">end</a>(); </pre> <p> If the system uses a virtual desktop, the returned widget willhave the geometry of the entire virtual desktop i.e. boundingevery <em>screen</em>.<p> <p>See also <a href="#primaryScreen">primaryScreen</a>(), <a href="#numScreens">numScreens</a>() and <a href="#isVirtualDesktop">isVirtualDesktop</a>().<h3 class=fn>const <a href="qrect.html">QRect</a> & <a name="screenGeometry"></a>QDesktopWidget::screenGeometry ( int screen = -1 ) const</h3>Returns the geometry of the screen with index <em>screen</em>.<p> <p>See also <a href="#screenNumber">screenNumber</a>().<h3 class=fn>int <a name="screenNumber"></a>QDesktopWidget::screenNumber ( <a href="qwidget.html">QWidget</a> * widget = 0 ) const</h3>Returns the index of the screen that contains the largestpart of <em>widget</em>, or -1 if the widget is not on a screen.<p> <p>See also <a href="#primaryScreen">primaryScreen</a>().<h3 class=fn>int <a name="screenNumber-2"></a>QDesktopWidget::screenNumber ( const <a href="qpoint.html">QPoint</a> & point ) const</h3>This is an overloaded member function, provided for convenience. It behaves essentially like the above function.<p> Returns the index of the screen that contains <em>point</em>, or -1 ifno screen contains the point.<p> <p>See also <a href="#primaryScreen">primaryScreen</a>().<!-- eof --><hr><p>This file is part of the <a href="index.html">Qt toolkit</a>.Copyright © 1995-2002<a href="http://www.trolltech.com/">Trolltech</a>. All Rights Reserved.<p><address><hr><div align=center><table width=100% cellspacing=0 border=0><tr><td>Copyright © 2002 <a href="http://www.trolltech.com">Trolltech</a><td><a href="http://www.trolltech.com/trademarks.html">Trademarks</a><td align=right><div align=right>Qt version 3.0.5</div></table></div></address></body></html>⌨️ 快捷键说明
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