Qt Toolkit - hello/main.cpp example file 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: white; color: black; } --> alt="Home" border="0"> height="100" src="face.png" alt="Home" border="0"> Classes - Annotated - Tree - Functions - Home - Structure Qte Hello, World This example brings up the words "Hello, World" moving up and down, and in different colors. Header file: /**************************************************************************** ** $Id: qt/examples/hello/hello.h 2.3.8 edited 2004-05-12 $ ** ** 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 <qwidget.h> class Hello : public QWidget { Q_OBJECT public: Hello( const char *text, QWidget *parent=0, const char *name=0 ); signals: void clicked(); protected: void mouseReleaseEvent( QMouseEvent * ); void paintEvent( QPaintEvent * ); private slots: void animate(); private: QString t; int b; }; #endif Implementation: /**************************************************************************** ** $Id: qt/examples/hello/hello.cpp 2.3.8 edited 2004-05-12 $ ** ** 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 <qpushbutton.h> #include <qtimer.h> #include <qpainter.h> #include <qpixmap.h> /* Constructs a Hello widget. Starts a 40 ms animation timer. */ Hello::Hello( const char *text, QWidget *parent, const char *name ) : QWidget(parent,name), t(text), b(0) { QTimer *timer = new QTimer(this); connect( timer, SIGNAL(timeout()), SLOT(animate()) ); timer->start( 40 ); resize( 260, 130 ); } /* This private slot is called each time the timer fires. */ void Hello::animate() { b = (b + 1) & 15; repaint( FALSE ); } /* Handles mouse button release events for the Hello widget. We emit the clicked() signal when the mouse is released inside the widget. */ void Hello::mouseReleaseEvent( QMouseEvent *e ) { if ( rect().contains( e->pos() ) ) 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::paintEvent( QPaintEvent * ) { 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. QFontMetrics fm = fontMetrics(); int w = fm.width(t) + 20; int h = fm.height() * 2; int pmx = width()/2 - w/2; int pmy = height()/2 - h/2; // 2: Create the pixmap and fill it with the widget's background QPixmap pm( w, h ); pm.fill( this, pmx, pmy ); // 3: Paint the pixmap. Cool wave effect QPainter p; int x = 10; int y = h/2 + fm.descent(); int i = 0; p.begin( &pm ); p.setFont( font() ); while ( !t[i].isNull() ) { int i16 = (b+i) & 15; p.setPen( QColor((15-i16)*16,255,255,QColor::Hsv) ); p.drawText( x, y-sin_tbl[i16]*h/800, t.mid(i,1), 1 ); x += fm.width( t[i] ); i++; } p.end(); // 4: Copy the pixmap to the Hello widget bitBlt( this, pmx, pmy, &pm ); } Main: /**************************************************************************** ** $Id: qt/examples/hello/main.cpp 2.3.8 edited 2004-05-12 $ ** ** 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 <qapplication.h> /* 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 ) { QApplication a(argc,argv); QString s; for ( int i=1; i<argc; i++ ) { s += argv[i]; if ( i<argc-1 ) s += " "; } if ( s.isEmpty() ) s = "Hello, World"; Hello h( s ); h.setCaption( "Qt says hello" ); QObject::connect( &h, SIGNAL(clicked()), &a, SLOT(quit()) ); h.setFont( QFont("times",32,QFont::Bold) ); // default font h.setBackgroundColor( Qt::white ); // default bg color a.setMainWidget( &h ); h.show(); return a.exec(); } Copyright
