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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/examples/hello/hello.doc:5 --><html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>Hello, World</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>Hello, World</h1> <p> This example brings up the words "Hello, World" moving up and down,and in different colors.<p> <hr><p> Header file:<p> <pre>/****************************************************************************** $Id: qt/hello.h 3.0.5 edited Oct 12 2001 $**** 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.*******************************************************************************/#ifndef HELLO_H#define HELLO_H#include <<a href="qwidget-h.html">qwidget.h</a>>class Hello : public <a href="qwidget.html">QWidget</a>{ <a href="metaobjects.html#Q_OBJECT">Q_OBJECT</a>public: Hello( const char *text, QWidget *parent=0, const char *name=0 );signals: void clicked();protected: void mouseReleaseEvent( <a href="qmouseevent.html">QMouseEvent</a> * ); void paintEvent( <a href="qpaintevent.html">QPaintEvent</a> * );private slots: void animate();private: <a href="qstring.html">QString</a> t; int b;};#endif</pre><p> <hr><p> Implementation:<p> <pre>/****************************************************************************** $Id: qt/hello.cpp 3.0.5 edited May 7 17:30 $**** 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 "hello.h"#include <<a href="qpushbutton-h.html">qpushbutton.h</a>>#include <<a href="qtimer-h.html">qtimer.h</a>>#include <<a href="qpainter-h.html">qpainter.h</a>>#include <<a href="qpixmap-h.html">qpixmap.h</a>>/* Constructs a Hello widget. Starts a 40 ms animation timer.*/<a name="f466"></a>Hello::Hello( const char *text, QWidget *parent, const char *name ) : <a href="qwidget.html">QWidget</a>(parent,name), t(text), b(0){ <a href="qtimer.html">QTimer</a> *timer = new <a href="qtimer.html">QTimer</a>(this);<a name="x1606"></a> <a href="qobject.html#connect">connect</a>( timer, SIGNAL(<a href="qtimer.html#timeout">timeout</a>()), SLOT(animate()) );<a name="x1605"></a> timer-><a href="qtimer.html#start">start</a>( 40 ); <a href="qwidget.html#resize">resize</a>( 260, 130 );}/* This private slot is called each time the timer fires.*/void <a name="f467"></a>Hello::animate(){ b = (b + 1) & 15; <a href="qwidget.html#repaint">repaint</a>( FALSE );}/* Handles mouse button release events for the Hello widget. We emit the clicked() signal when the mouse is released inside the widget.*/<a name="x1607"></a>void Hello::<a href="qwidget.html#mouseReleaseEvent">mouseReleaseEvent</a>( <a href="qmouseevent.html">QMouseEvent</a> *e ){ if ( <a href="qwidget.html#rect">rect</a>().contains( e-><a href="qmouseevent.html#pos">pos</a>() ) ) emit clicked();}/* Handles paint events for the Hello widget. Flicker-free update. The text is first drawn in the pixmap and the pixmap is then blt'ed to the screen.*/void Hello::<a href="qwidget.html#paintEvent">paintEvent</a>( <a href="qpaintevent.html">QPaintEvent</a> * ){ static int sin_tbl[16] = { 0, 38, 71, 92, 100, 92, 71, 38, 0, -38, -71, -92, -100, -92, -71, -38}; if ( t.isEmpty() ) return; // 1: Compute some sizes, positions etc. <a href="qfontmetrics.html">QFontMetrics</a> fm = <a href="qwidget.html#fontMetrics">fontMetrics</a>();<a name="x1597"></a> int w = fm.<a href="qfontmetrics.html#width">width</a>(t) + 20;<a name="x1596"></a> int h = fm.<a href="qfontmetrics.html#height">height</a>() * 2; int pmx = <a href="qwidget.html#width">width</a>()/2 - w/2; int pmy = <a href="qwidget.html#height">height</a>()/2 - h/2; // 2: Create the pixmap and fill it with the widget's background <a href="qpixmap.html">QPixmap</a> pm( w, h );<a name="x1604"></a> pm.<a href="qpixmap.html#fill">fill</a>( this, pmx, pmy ); // 3: Paint the pixmap. Cool wave effect <a href="qpainter.html">QPainter</a> p; int x = 10;<a name="x1595"></a> int y = h/2 + fm.<a href="qfontmetrics.html#descent">descent</a>(); int i = 0;<a name="x1599"></a> p.<a href="qpainter.html#begin">begin</a>( &pm );<a name="x1602"></a> p.<a href="qpainter.html#setFont">setFont</a>( <a href="qwidget.html#font">font</a>() ); while ( !t[i].isNull() ) { int i16 = (b+i) & 15; p.<a href="qpainter.html#setPen">setPen</a>( QColor((15-i16)*16,255,255,QColor::Hsv) ); p.<a href="qpainter.html#drawText">drawText</a>( x, y-sin_tbl[i16]*h/800, t.mid(i,1), 1 ); x += fm.<a href="qfontmetrics.html#width">width</a>( t[i] ); i++; }<a name="x1601"></a> p.<a href="qpainter.html#end">end</a>(); // 4: Copy the pixmap to the Hello widget <a href="qpaintdevice.html#bitBlt-2">bitBlt</a>( this, pmx, pmy, &pm );}</pre><p> <hr><p> Main:<p> <pre>/****************************************************************************** $Id: qt/main.cpp 3.0.5 edited Oct 12 2001 $**** 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 "hello.h"#include <<a href="qapplication-h.html">qapplication.h</a>>/* The program starts here. It parses the command line and builds a message string to be displayed by the Hello widget.*/int main( int argc, char **argv ){ <a href="qapplication.html">QApplication</a> a(argc,argv); <a href="qstring.html">QString</a> s; for ( int i=1; i<argc; i++ ) { s += argv[i]; if ( i<argc-1 ) s += " "; } if ( s.<a href="qstring.html#isEmpty">isEmpty</a>() ) s = "Hello, World"; Hello h( s );#ifndef QT_NO_WIDGET_TOPEXTRA // for Qt/Embedded minimal build h.<a href="qwidget.html#setCaption">setCaption</a>( "Qt says hello" );#endif QObject::<a href="qobject.html#connect">connect</a>( &h, SIGNAL(clicked()), &a, SLOT(<a href="qapplication.html#quit">quit</a>()) );<a name="x1616"></a> h.<a href="qwidget.html#setFont">setFont</a>( QFont("times",32,QFont::Bold) ); // default font<a name="x1614"></a> h.<a href="qwidget.html#setBackgroundColor">setBackgroundColor</a>( Qt::white ); // default bg color a.<a href="qapplication.html#setMainWidget">setMainWidget</a>( &h ); h.<a href="qwidget.html#show">show</a>(); return a.<a href="qapplication.html#exec">exec</a>();}</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 © 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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