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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
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Qt Toolkit - forever/forever.cpp example file
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<h1 align=center>A Rectangle Draw "Benchmark"</h1><br clear="all">
This example continuously draws rectangles in a window and
has another widget that counts the number of rectangles that
are drawn per second.
<hr>
Header file: <pre>/****************************************************************************
** $Id: qt/examples/forever/forever.h 2.3.2 edited 2001-01-26 $
**
** Definition of something or other
**
** Created : 979899
**
** Copyright (C) 1997 by Trolltech AS. 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 QWidget
{
Q_OBJECT
public:
Forever( <a href="qwidget.html">QWidget</a> *parent=0, const char *name=0 );
protected:
void timerEvent( <a href="qtimerevent.html">QTimerEvent</a> * );
private slots:
void updateCaption();
private:
int rectangles;
<a href="qcolor.html">QColor</a> colors[numColors];
};
#endif
</pre>
<hr>
Implementation:
<pre>/****************************************************************************
** $Id: qt/examples/forever/forever.cpp 2.3.2 edited 2001-10-18 $
**
** Copyright (C) 1992-2000 Trolltech AS. 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 name="qtimer.h"></a><a href="qtimer-h.html">qtimer.h</a>>
#include <<a name="qpainter.h"></a><a href="qpainter-h.html">qpainter.h</a>>
#include <<a name="qapplication.h"></a><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.
//
Forever::Forever( <a name="QWidget"></a><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 name="startTimer"></a><a href="qobject.html#4c6b67">startTimer</a>( 0 ); // run continuous timer
<a name="QTimer"></a><a href="qtimer.html">QTimer</a> * counter = new <a href="qtimer.html">QTimer</a>( this );
<a name="connect"></a><a href="qobject.html#7f8e37">connect</a>( counter, SIGNAL(timeout()),
this, SLOT(<a name="updateCaption"></a><a href="#333">updateCaption</a>()) );
counter-><a name="start"></a><a href="qtimer.html#ce33bc">start</a>( 1000 );
}
void <a name="333"></a>Forever::updateCaption()
{
<a name="QString"></a><a href="qstring.html">QString</a> s;
s.<a name="sprintf"></a><a href="qstring.html#926f67">sprintf</a>( "Qt Example - Forever - %d rectangles/second", rectangles );
rectangles = 0;
<a name="setCaption"></a><a href="qwidget.html#d6a291">setCaption</a>( s );
}
//
// Handles timer events for the Forever widget.
//
void <a name="334"></a>Forever::timerEvent( <a name="QTimerEvent"></a><a href="qtimerevent.html">QTimerEvent</a> * )
{
<a name="QPainter"></a><a href="qpainter.html">QPainter</a> paint( this ); // painter object
paint.<a name="setPen"></a><a href="qpainter.html#0183e4">setPen</a>( NoPen ); // do not draw outline
int w = width();
int h = height();
if( w <= 0 || h <= 0 )
return;
for ( int i=0; i<100; i++ ) {
paint.<a name="setBrush"></a><a href="qpainter.html#3e0cc8">setBrush</a>( colors[i % numColors]); // set random brush color
<a name="QPoint"></a><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 name="QRect"></a><a href="qrect.html">QRect</a> r( p1, p2 );
paint.<a name="drawRect"></a><a href="qpainter.html#4c0077">drawRect</a>( r ); // draw filled rectangle
rectangles++;
}
}
//
// Create and display Forever widget.
//
int main( int argc, char **argv )
{
<a name="QApplication"></a><a href="qapplication.html">QApplication</a> a( argc, argv ); // create application object
Forever always; // create widget
a.<a name="setMainWidget"></a><a href="qapplication.html#7ad759">setMainWidget</a>( &always ); // set as main widget
always.<a href="qwidget.html#d6a291">setCaption</a>("Qt Example - Forever");
always.<a name="show"></a><a href="qwidget.html#200ee5">show</a>(); // show widget
return a.<a name="exec"></a><a href="qapplication.html#84c7bf">exec</a>(); // run event loop
}
</pre>
<p><address><hr><div align="center">
<table width="100%" cellspacing="0" border="0"><tr>
<td>Copyright 2001 Trolltech<td><a href="http://www.trolltech.com/trademarks.html">Trademarks</a>
<td align="right"><div align="right">Qt version 2.3.2</div>
</table></div></address></body></html>
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