<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <!-- /home/espenr/tmp/qt-3.3.8-espenr-2499/qt-x11-free-3.3.8/examples/forever/forever.doc:5 --> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> <title>A Rectangle Draw "Benchmark"</title> <style type="text/css"><!-- 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>A Rectangle Draw "Benchmark"</h1> <p> This example continuously draws rectangles in a window and has another widget that counts the number of rectangles that are drawn per second. <p> <hr> <p> Header file: <p> <pre>/**************************************************************************** ** $Id: qt/forever.h 3.3.8 edited Jan 11 14:46 $ ** ** Definition of something or other ** ** Created : 979899 ** ** Copyright (C) 1997-2007 Trolltech ASA. All rights reserved. ** ** This file is part of an example program for Qt. This example ** program may be used, distributed and modified without limitation. ** *****************************************************************************/ #ifndef FOREVER_H #define FOREVER_H #include <<a href="qwidget-h.html">qwidget.h</a>> const int numColors = 120; class Forever : public <a href="qwidget.html">QWidget</a> { <a href="metaobjects.html#Q_OBJECT">Q_OBJECT</a> public: Forever( <a href="qwidget.html">QWidget</a> *parent=0, const char *name=0 ); protected: void paintEvent( <a href="qpaintevent.html">QPaintEvent</a> * ); void timerEvent( <a href="qtimerevent.html">QTimerEvent</a> * ); private slots: void updateCaption(); private: int rectangles; QColor colors[numColors]; }; #endif </pre> <p> <hr> <p> Implementation: <p> <pre>/**************************************************************************** ** $Id: qt/forever.cpp 3.3.8 edited Jan 11 14:37 $ ** ** Copyright (C) 1992-2007 Trolltech ASA. All rights reserved. ** ** This file is part of an example program for Qt. This example ** program may be used, distributed and modified without limitation. ** *****************************************************************************/ #include <<a href="qtimer-h.html">qtimer.h</a>> #include <<a href="qpainter-h.html">qpainter.h</a>> #include <<a href="qapplication-h.html">qapplication.h</a>> #include <stdlib.h> // defines rand() function #include "forever.h" // // Forever - a widget that draws rectangles forever. // // // Constructs a Forever widget. // <a name="f365"></a>Forever::Forever( <a href="qwidget.html">QWidget</a> *parent, const char *name ) : <a href="qwidget.html">QWidget</a>( parent, name ) { for (int a=0; a<numColors; a++) { colors[a] = QColor( rand()&255, rand()&255, rand()&255 ); } rectangles = 0; <a href="qobject.html#startTimer">startTimer</a>( 0 ); // run continuous timer <a href="qtimer.html">QTimer</a> * counter = new <a href="qtimer.html">QTimer</a>( this ); <a name="x1054"></a> <a href="qobject.html#connect">connect</a>( counter, SIGNAL(<a href="qtimer.html#timeout">timeout</a>()), this, SLOT(updateCaption()) ); <a name="x1053"></a> counter-><a href="qtimer.html#start">start</a>( 1000 ); } void <a name="f366"></a>Forever::updateCaption() { <a href="qstring.html">QString</a> s; <a name="x1052"></a> s.<a href="qstring.html#sprintf">sprintf</a>( "Qt Example - Forever - %d rectangles/second", rectangles ); rectangles = 0; <a href="qwidget.html#setCaption">setCaption</a>( s ); } // // Handles paint events for the Forever widget. // <a name="x1055"></a>void Forever::<a href="qwidget.html#paintEvent">paintEvent</a>( <a href="qpaintevent.html">QPaintEvent</a> * ) { <a href="qpainter.html">QPainter</a> paint( this ); // painter object int w = <a href="qwidget.html#width">width</a>(); int h = <a href="qwidget.html#height">height</a>(); if(w <= 0 || h <= 0) return; paint.<a href="qpainter.html#setPen">setPen</a>( NoPen ); // do not draw outline paint.<a href="qpainter.html#setBrush">setBrush</a>( colors[rand() % numColors]);// set random brush color <a href="qpoint.html">QPoint</a> p1( rand()%w, rand()%h ); // p1 = top left <a href="qpoint.html">QPoint</a> p2( rand()%w, rand()%h ); // p2 = bottom right <a href="qrect.html">QRect</a> r( p1, p2 ); paint.<a href="qpainter.html#drawRect">drawRect</a>( r ); // draw filled rectangle } // // Handles timer events for the Forever widget. // <a name="x1048"></a>void Forever::<a href="qobject.html#timerEvent">timerEvent</a>( <a href="qtimerevent.html">QTimerEvent</a> * ) { for ( int i=0; i<100; i++ ) { <a href="qwidget.html#repaint">repaint</a>( FALSE ); // repaint, don't erase rectangles++; } } // // Create and display Forever widget. // int main( int argc, char **argv ) { <a href="qapplication.html">QApplication</a> a( argc, argv ); // create application object Forever always; // create widget always.<a href="qwidget.html#resize">resize</a>( 400, 250 ); // start up with size 400x250 a.<a href="qapplication.html#setMainWidget">setMainWidget</a>( &always ); // set as main widget always.<a href="qwidget.html#setCaption">setCaption</a>("Qt Example - Forever"); always.<a href="qwidget.html#show">show</a>(); // show widget return a.<a href="qapplication.html#exec">exec</a>(); // run event loop } </pre> <p>See also <a href="examples.html">Examples</a>. <!-- eof --> <p><address><hr><div align=center> <table width=100% cellspacing=0 border=0><tr> <td>Copyright © 2007 <a href="troll.html">Trolltech</a><td align=center><a href="trademarks.html">Trademarks</a> <td align=right><div align=right>Qt 3.3.8</div> </table></div></address></body> </html>