The example program on this page may be used, distributed and modified without limitation. C0664 510077 qtdoc-1.2-a4-2.ps

Advanced use of tool tips

This example widget demonstrates how to use tool tips for static and dynamic regions within a widget. It displays two blue and one red rectangle. The blue ones move every time you click on them, the red one is static. There are dynamic tool tips on the blue rectangles and a static tool tip on the red one.
//
// $Id: tooltip.cpp,v 1.3 1997/03/26 18:25:57 hanord Exp $
//
// A widget to demonstrate tool tips
//

#include "tooltip.h"
#include <qapp.h>
#include <qpainter.h>
#include <stdlib.h>

DynamicTip::DynamicTip( QWidget * parent )
    : QToolTip( parent )
{
    // no explicit initialization needed
}

void DynamicTip::maybeTip( const QPoint &pos )
{
    if ( !parentWidget()->inherits( "TellMe" ) )
        return;

    QRect r( ((TellMe*)parentWidget())->tip(pos) );
    if ( !r.isValid() )
        return;

    QString s;
    s.sprintf( "position: %d,%d", r.center().x(), r.center().y() );
    tip( r, s );
}

TellMe::TellMe( QWidget * parent , const char * name  )
    : QWidget( parent, name )
{
    setMinimumSize( 30, 30 );
    r1 = randomRect();
    r2 = randomRect();
    r3 = randomRect();

    t = new DynamicTip( this );

    QToolTip::add( this, r3, "this color is called red" ); // <- helpful
}

TellMe::~TellMe()
{
    delete t;
    t = 0;
}

void TellMe::paintEvent( QPaintEvent * e )
{
    QPainter p( this );

    // I try to be efficient here, and repaint only what's needed

    if ( e->rect().intersects( r1 ) ) {
        p.setBrush( blue );
        p.drawRect( r1 );
    }

    if ( e->rect().intersects( r2 ) ) {
        p.setBrush( blue );
        p.drawRect( r2 );
    }

    if ( e->rect().intersects( r3 ) ) {
        p.setBrush( red );
        p.drawRect( r3 );
    }
}

void TellMe::mousePressEvent( QMouseEvent * e )
{
    if ( r1.contains( e->pos() ) )
        r1 = randomRect();
    if ( r2.contains( e->pos() ) )
        r2 = randomRect();
    repaint();
}

void TellMe::resizeEvent( QResizeEvent * )
{
    if ( !rect().contains( r1 ) )
         r1 = randomRect();
    if ( !rect().contains( r2 ) )
         r2 = randomRect();
}

QRect TellMe::randomRect()
{
    return QRect( ::rand() % (width() - 20), ::rand() % (height() - 20),
                  20, 20 );
}

QRect TellMe::tip( const QPoint & p )
{
    if ( r1.contains( p ) )
        return r1;
    else if ( r2.contains( p ) )
        return r2;
    else
        return QRect( 0,0, -1,-1 );
}

Generated at 17:29, 1997/04/07 for Qt version 1.2 by the webmaster at Troll Tech