/****************************************************************************** $Id: qt/hello.cpp 3.3.3 edited May 27 2003 $**** 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 );}
