qwt_counter.cpp

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/* -*- mode: C++ ; c-file-style: "stroustrup" -*- *****************************
 * Qwt Widget Library
 * Copyright (C) 1997   Josef Wilgen
 * Copyright (C) 2002   Uwe Rathmann
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the Qwt License, Version 1.0
 *****************************************************************************/

#include "qwt_arrow_button.h"
#include "qwt_math.h"
#include "qwt_counter.h"
#include <qlayout.h>
#include <qlineedit.h>
#include <qvalidator.h>
#include <qevent.h>
#include <qstyle.h>

class QwtCounter::PrivateData
{
public:
    PrivateData():
        minimum( 0.0 ),
        maximum( 0.0 ),
        singleStep( 1.0 ),
        isValid( false ),
        value( 0.0 ),
        wrapping( false )
    {
        increment[Button1] = 1;
        increment[Button2] = 10;
        increment[Button3] = 100;
    }

    QwtArrowButton *buttonDown[ButtonCnt];
    QwtArrowButton *buttonUp[ButtonCnt];
    QLineEdit *valueEdit;

    int increment[ButtonCnt];
    int numButtons;

    double minimum;
    double maximum;
    double singleStep;

    bool isValid;
    double value;

    bool wrapping;
};

QwtCounter::QwtCounter( QWidget *parent ):
    QWidget( parent )
{
    initCounter();
}

void QwtCounter::initCounter()
{
    d_data = new PrivateData;

    QHBoxLayout *layout = new QHBoxLayout( this );
    layout->setSpacing( 0 );
    layout->setMargin( 0 );

    for ( int i = ButtonCnt - 1; i >= 0; i-- )
    {
        QwtArrowButton *btn =
            new QwtArrowButton( i + 1, Qt::DownArrow, this );
        btn->setFocusPolicy( Qt::NoFocus );
        layout->addWidget( btn );

        connect( btn, SIGNAL( released() ), SLOT( btnReleased() ) );
        connect( btn, SIGNAL( clicked() ), SLOT( btnClicked() ) );

        d_data->buttonDown[i] = btn;
    }

    d_data->valueEdit = new QLineEdit( this );
    d_data->valueEdit->setReadOnly( false );
    d_data->valueEdit->setValidator( new QDoubleValidator( d_data->valueEdit ) );
    layout->addWidget( d_data->valueEdit );

    connect( d_data->valueEdit, SIGNAL( editingFinished() ),
         SLOT( textChanged() ) );

    layout->setStretchFactor( d_data->valueEdit, 10 );

    for ( int i = 0; i < ButtonCnt; i++ )
    {
        QwtArrowButton *btn =
            new QwtArrowButton( i + 1, Qt::UpArrow, this );
        btn->setFocusPolicy( Qt::NoFocus );
        layout->addWidget( btn );

        connect( btn, SIGNAL( released() ), SLOT( btnReleased() ) );
        connect( btn, SIGNAL( clicked() ), SLOT( btnClicked() ) );

        d_data->buttonUp[i] = btn;
    }

    setNumButtons( 2 );
    setRange( 0.0, 1.0 );
    setSingleStep( 0.001 );
    setValue( 0.0 );

    setSizePolicy(
        QSizePolicy( QSizePolicy::Preferred, QSizePolicy::Fixed ) );

    setFocusProxy( d_data->valueEdit );
    setFocusPolicy( Qt::StrongFocus );
}

QwtCounter::~QwtCounter()
{
    delete d_data;
}

void QwtCounter::setValid( bool on )
{
    if ( on != d_data->isValid )
    {
        d_data->isValid = on;

        updateButtons();

        if ( d_data->isValid )
        {
            showNumber( value() );
            Q_EMIT valueChanged( value() );
        }
        else
        {
            d_data->valueEdit->setText( QString::null );
        }
    }   
}   

bool QwtCounter::isValid() const
{
    return d_data->isValid;
}   

void QwtCounter::setReadOnly( bool on )
{
    d_data->valueEdit->setReadOnly( on );
}

bool QwtCounter::isReadOnly() const
{
    return d_data->valueEdit->isReadOnly();
}

void QwtCounter::setValue( double value )
{
    const double vmin = qMin( d_data->minimum, d_data->maximum );
    const double vmax = qMax( d_data->minimum, d_data->maximum );

    value = qBound( vmin, value, vmax );

    if ( !d_data->isValid || value != d_data->value )
    {
        d_data->isValid = true;
        d_data->value = value;

        showNumber( value );
        updateButtons();

        Q_EMIT valueChanged( value );
    }
}

double QwtCounter::value() const
{
    return d_data->value;
}

void QwtCounter::setRange( double min, double max )
{
    max = qMax( min, max );

    if ( d_data->maximum == max && d_data->minimum == min )
        return;

    d_data->minimum = min;
    d_data->maximum = max;

    setSingleStep( singleStep() );

    const double value = qBound( min, d_data->value, max );

    if ( value != d_data->value )
    {
        d_data->value = value;

        if ( d_data->isValid )
        {
            showNumber( value );
            Q_EMIT valueChanged( value );
        }
    }

    updateButtons();
}

void QwtCounter::setMinimum( double value )
{
    setRange( value, maximum() );
}

double QwtCounter::minimum() const
{
    return d_data->minimum;
}

void QwtCounter::setMaximum( double value )
{
    setRange( minimum(), value );
}

double QwtCounter::maximum() const
{
    return d_data->maximum;
}

void QwtCounter::setSingleStep( double stepSize )
{
    d_data->singleStep = qMax( stepSize, 0.0 );
}

double QwtCounter::singleStep() const
{
    return d_data->singleStep;
}

void QwtCounter::setWrapping( bool on )
{
    d_data->wrapping = on;
}

bool QwtCounter::wrapping() const
{
    return d_data->wrapping;
}

void QwtCounter::setNumButtons( int numButtons )
{
    if ( numButtons < 0 || numButtons > QwtCounter::ButtonCnt )
        return;

    for ( int i = 0; i < QwtCounter::ButtonCnt; i++ )
    {
        if ( i < numButtons )
        {
            d_data->buttonDown[i]->show();
            d_data->buttonUp[i]->show();
        }
        else
        {
            d_data->buttonDown[i]->hide();
            d_data->buttonUp[i]->hide();
        }
    }

    d_data->numButtons = numButtons;
}

int QwtCounter::numButtons() const
{
    return d_data->numButtons;
}

void QwtCounter::setIncSteps( QwtCounter::Button button, int numSteps )
{
    if ( button >= 0 && button < QwtCounter::ButtonCnt )
        d_data->increment[ button ] = numSteps;
}

int QwtCounter::incSteps( QwtCounter::Button button ) const
{
    if ( button >= 0 && button < QwtCounter::ButtonCnt )
        return d_data->increment[ button ];

    return 0;
}


void QwtCounter::setStepButton1( int nSteps )
{
    setIncSteps( QwtCounter::Button1, nSteps );
}

int QwtCounter::stepButton1() const
{
    return incSteps( QwtCounter::Button1 );
}

void QwtCounter::setStepButton2( int nSteps )
{
    setIncSteps( QwtCounter::Button2, nSteps );
}

int QwtCounter::stepButton2() const
{
    return incSteps( QwtCounter::Button2 );
}

void QwtCounter::setStepButton3( int nSteps )
{
    setIncSteps( QwtCounter::Button3, nSteps );
}

int QwtCounter::stepButton3() const
{
    return incSteps( QwtCounter::Button3 );
}

void QwtCounter::textChanged()
{
    bool converted = false;

    const double value = d_data->valueEdit->text().toDouble( &converted );
    if ( converted )
        setValue( value );
}

bool QwtCounter::event( QEvent *event )
{
    if ( event->type() == QEvent::PolishRequest )
    {
        const int w = d_data->valueEdit->fontMetrics().width( "W" ) + 8;
        for ( int i = 0; i < ButtonCnt; i++ )
        {
            d_data->buttonDown[i]->setMinimumWidth( w );
            d_data->buttonUp[i]->setMinimumWidth( w );
        }
    }

    return QWidget::event( event );
}

void QwtCounter::keyPressEvent ( QKeyEvent *event )
{
    bool accepted = true;

    switch ( event->key() )
    {
        case Qt::Key_Home:
        {
            if ( event->modifiers() & Qt::ControlModifier )
                setValue( minimum() );
            else
                accepted = false;
            break;
        }
        case Qt::Key_End:
        {
            if ( event->modifiers() & Qt::ControlModifier )
                setValue( maximum() );
            else
                accepted = false;
            break;
        }
        case Qt::Key_Up:
        {
            incrementValue( d_data->increment[0] );
            break;
        }
        case Qt::Key_Down:
        {
            incrementValue( -d_data->increment[0] );
            break;
        }
        case Qt::Key_PageUp:
        case Qt::Key_PageDown:
        {
            int increment = d_data->increment[0];
            if ( d_data->numButtons >= 2 )
                increment = d_data->increment[1];
            if ( d_data->numButtons >= 3 )
            {
                if ( event->modifiers() & Qt::ShiftModifier )
                    increment = d_data->increment[2];
            }
            if ( event->key() == Qt::Key_PageDown )
                increment = -increment;
            incrementValue( increment );
            break;
        }
        default:
        {
            accepted = false;
        }
    }

    if ( accepted )
    {
        event->accept();
        return;
    }

    QWidget::keyPressEvent ( event );
}

void QwtCounter::wheelEvent( QWheelEvent *event )
{
    event->accept();

    if ( d_data->numButtons <= 0 )
        return;

    int increment = d_data->increment[0];
    if ( d_data->numButtons >= 2 )
    {
        if ( event->modifiers() & Qt::ControlModifier )
            increment = d_data->increment[1];
    }
    if ( d_data->numButtons >= 3 )
    {
        if ( event->modifiers() & Qt::ShiftModifier )
            increment = d_data->increment[2];
    }

    for ( int i = 0; i < d_data->numButtons; i++ )
    {
        if ( d_data->buttonDown[i]->geometry().contains( event->pos() ) ||
            d_data->buttonUp[i]->geometry().contains( event->pos() ) )
        {
            increment = d_data->increment[i];
        }
    }

    const int wheel_delta = 120;

#if 1
    int delta = event->delta();
    if ( delta >= 2 * wheel_delta )
        delta /= 2; // Never saw an abs(delta) < 240
#endif

    incrementValue( delta / wheel_delta * increment );
}

void QwtCounter::incrementValue( int numSteps )
{
    const double min = d_data->minimum;
    const double max = d_data->maximum;
    double stepSize = d_data->singleStep;

    if ( !d_data->isValid || min >= max || stepSize <= 0.0 )
        return;


#if 1
    stepSize = qMax( stepSize, 1.0e-10 * ( max - min ) );
#endif

    double value = d_data->value + numSteps * stepSize;

    if ( d_data->wrapping )
    {
        const double range = max - min;

        if ( value < min )
        {
            value += ::ceil( ( min - value ) / range ) * range;
        }
        else if ( value > max )
        {
            value -= ::ceil( ( value - max ) / range ) * range;
        }
    }
    else
    {
        value = qBound( min, value, max );
    }

    value = min + qRound( ( value - min ) / stepSize ) * stepSize;

    if ( stepSize > 1e-12 )
    {
        if ( qFuzzyCompare( value + 1.0, 1.0 ) )
        {
            // correct rounding error if value = 0
            value = 0.0;
        }
        else if ( qFuzzyCompare( value, max ) )
        {
            // correct rounding error at the border
            value = max;
        }
    }

    if ( value != d_data->value )
    {
        d_data->value = value;
        showNumber( d_data->value );
        updateButtons();

        Q_EMIT valueChanged( d_data->value );
    }
}


void QwtCounter::updateButtons()
{
    if ( d_data->isValid )
    {
        // 1. save enabled state of the smallest down- and up-button
        // 2. change enabled state on under- or over-flow

        for ( int i = 0; i < QwtCounter::ButtonCnt; i++ )
        {
            d_data->buttonDown[i]->setEnabled( value() > minimum() );
            d_data->buttonUp[i]->setEnabled( value() < maximum() );
        }
    }
    else
    {
        for ( int i = 0; i < QwtCounter::ButtonCnt; i++ )
        {
            d_data->buttonDown[i]->setEnabled( false );
            d_data->buttonUp[i]->setEnabled( false );
        }
    }
}
void QwtCounter::showNumber( double number )
{
    QString text;
    text.setNum( number );

    const int cursorPos = d_data->valueEdit->cursorPosition();
    d_data->valueEdit->setText( text );
    d_data->valueEdit->setCursorPosition( cursorPos );
}

void QwtCounter::btnClicked()
{
    for ( int i = 0; i < ButtonCnt; i++ )
    {
        if ( d_data->buttonUp[i] == sender() )
            incrementValue( d_data->increment[i] );

        if ( d_data->buttonDown[i] == sender() )
            incrementValue( -d_data->increment[i] );
    }
}

void QwtCounter::btnReleased()
{
    Q_EMIT buttonReleased( value() );
}

QSize QwtCounter::sizeHint() const
{
    QString tmp;

    int w = tmp.setNum( minimum() ).length();
    int w1 = tmp.setNum( maximum() ).length();
    if ( w1 > w )
        w = w1;
    w1 = tmp.setNum( minimum() + singleStep() ).length();
    if ( w1 > w )
        w = w1;
    w1 = tmp.setNum( maximum() - singleStep() ).length();
    if ( w1 > w )
        w = w1;

    tmp.fill( '9', w );

    QFontMetrics fm( d_data->valueEdit->font() );
    w = fm.width( tmp ) + 2;
    if ( d_data->valueEdit->hasFrame() )
        w += 2 * style()->pixelMetric( QStyle::PM_DefaultFrameWidth );

    // Now we replace default sizeHint contribution of d_data->valueEdit by
    // what we really need.

    w += QWidget::sizeHint().width() - d_data->valueEdit->sizeHint().width();

    const int h = qMin( QWidget::sizeHint().height(),
        d_data->valueEdit->minimumSizeHint().height() );
    return QSize( w, h );
}