qwt_wheel.cpp

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/******************************************************************************
 * 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_wheel.h"
#include "qwt_math.h"
#include "qwt_painter.h"
#include "qwt.h"
 
#include <qevent.h>
#include <qdrawutil.h>
#include <qpainter.h>
#include <qstyle.h>
#include <qstyleoption.h>
#include <qelapsedtimer.h>
#include <qmath.h>
 
class QwtWheel::PrivateData
{
  public:
    PrivateData()
        : orientation( Qt::Horizontal )
        , viewAngle( 175.0 )
        , totalAngle( 360.0 )
        , tickCount( 10 )
        , wheelBorderWidth( 2 )
        , borderWidth( 2 )
        , wheelWidth( 20 )
        , mouseOffset( 0.0 )
        , updateInterval( 50 )
        , mass( 0.0 )
        , timerId( 0 )
        , speed( 0.0 )
        , mouseValue( 0.0 )
        , flyingValue( 0.0 )
        , minimum( 0.0 )
        , maximum( 100.0 )
        , singleStep( 1.0 )
        , pageStepCount( 1 )
        , value( 0.0 )
        , isScrolling( false )
        , tracking( true )
        , stepAlignment( true )
        , pendingValueChanged( false )
        , inverted( false )
        , wrapping( false )
    {
    }
 
    Qt::Orientation orientation;
    double viewAngle;
    double totalAngle;
    int tickCount;
    int wheelBorderWidth;
    int borderWidth;
    int wheelWidth;
 
    double mouseOffset;
 
    int updateInterval;
    double mass;
 
    // for the flying wheel effect
    int timerId;
    QElapsedTimer timer;
    double speed;
    double mouseValue;
    double flyingValue;
 
    double minimum;
    double maximum;
 
    double singleStep;
    int pageStepCount;
 
    double value;
 
    bool isScrolling;
    bool tracking;
    bool stepAlignment;
    bool pendingValueChanged; // when not tracking
    bool inverted;
    bool wrapping;
};
 
QwtWheel::QwtWheel( QWidget* parent ):
    QWidget( parent )
{
    m_data = new PrivateData;
 
    setFocusPolicy( Qt::StrongFocus );
    setSizePolicy( QSizePolicy::Preferred, QSizePolicy::Fixed );
    setAttribute( Qt::WA_WState_OwnSizePolicy, false );
}
 
QwtWheel::~QwtWheel()
{
    delete m_data;
}
 
void QwtWheel::setTracking( bool enable )
{
    m_data->tracking = enable;
}
 
bool QwtWheel::isTracking() const
{
    return m_data->tracking;
}
 
void QwtWheel::setUpdateInterval( int interval )
{
    m_data->updateInterval = qMax( interval, 50 );
}
 
int QwtWheel::updateInterval() const
{
    return m_data->updateInterval;
}
 
void QwtWheel::mousePressEvent( QMouseEvent* event )
{
    stopFlying();
 
    m_data->isScrolling = wheelRect().contains( event->pos() );
 
    if ( m_data->isScrolling )
    {
        m_data->timer.start();
        m_data->speed = 0.0;
        m_data->mouseValue = valueAt( event->pos() );
        m_data->mouseOffset = m_data->mouseValue - m_data->value;
        m_data->pendingValueChanged = false;
 
        Q_EMIT wheelPressed();
    }
}
 
void QwtWheel::mouseMoveEvent( QMouseEvent* event )
{
    if ( !m_data->isScrolling )
        return;
 
    double mouseValue = valueAt( event->pos() );
 
    if ( m_data->mass > 0.0 )
    {
        double ms = m_data->timer.restart();
 
        // the interval when mouse move events are posted are somehow
        // random. To avoid unrealistic speed values we limit ms
 
        ms = qMax( ms, 5.0 );
 
        m_data->speed = ( mouseValue - m_data->mouseValue ) / ms;
    }
 
    m_data->mouseValue = mouseValue;
 
    double value = boundedValue( mouseValue - m_data->mouseOffset );
    if ( m_data->stepAlignment )
        value = alignedValue( value );
 
    if ( value != m_data->value )
    {
        m_data->value = value;
 
        update();
 
        Q_EMIT wheelMoved( m_data->value );
 
        if ( m_data->tracking )
            Q_EMIT valueChanged( m_data->value );
        else
            m_data->pendingValueChanged = true;
    }
}
 
void QwtWheel::mouseReleaseEvent( QMouseEvent* event )
{
    Q_UNUSED( event );
 
    if ( !m_data->isScrolling )
        return;
 
    m_data->isScrolling = false;
 
    bool startFlying = false;
 
    if ( m_data->mass > 0.0 )
    {
        const qint64 ms = m_data->timer.elapsed();
        if ( ( std::fabs( m_data->speed ) > 0.0 ) && ( ms < 50 ) )
            startFlying = true;
    }
 
    if ( startFlying )
    {
        m_data->flyingValue =
            boundedValue( m_data->mouseValue - m_data->mouseOffset );
 
        m_data->timerId = startTimer( m_data->updateInterval );
    }
    else
    {
        if ( m_data->pendingValueChanged )
            Q_EMIT valueChanged( m_data->value );
    }
 
    m_data->pendingValueChanged = false;
    m_data->mouseOffset = 0.0;
 
    Q_EMIT wheelReleased();
}
 
void QwtWheel::timerEvent( QTimerEvent* event )
{
    if ( event->timerId() != m_data->timerId )
    {
        QWidget::timerEvent( event );
        return;
    }
 
    m_data->speed *= std::exp( -m_data->updateInterval * 0.001 / m_data->mass );
 
    m_data->flyingValue += m_data->speed * m_data->updateInterval;
    m_data->flyingValue = boundedValue( m_data->flyingValue );
 
    double value = m_data->flyingValue;
    if ( m_data->stepAlignment )
        value = alignedValue( value );
 
    if ( std::fabs( m_data->speed ) < 0.001 * m_data->singleStep )
    {
        // stop if m_data->speed < one step per second
        stopFlying();
    }
 
    if ( value != m_data->value )
    {
        m_data->value = value;
        update();
 
        if ( m_data->tracking || m_data->timerId == 0 )
            Q_EMIT valueChanged( m_data->value );
    }
}
 
 
void QwtWheel::wheelEvent( QWheelEvent* event )
{
#if QT_VERSION < 0x050e00
    const QPoint wheelPos = event->pos();
    const int wheelDelta = event->delta();
#else
    const QPoint wheelPos = event->position().toPoint();
 
    const QPoint delta = event->angleDelta();
    const int wheelDelta = ( qAbs( delta.x() ) > qAbs( delta.y() ) )
        ? delta.x() : delta.y();
#endif
 
    if ( !wheelRect().contains( wheelPos ) )
    {
        event->ignore();
        return;
    }
 
    if ( m_data->isScrolling )
        return;
 
    stopFlying();
 
    double increment = 0.0;
 
    if ( ( event->modifiers() & Qt::ControlModifier ) ||
        ( event->modifiers() & Qt::ShiftModifier ) )
    {
        // one page regardless of delta
        increment = m_data->singleStep * m_data->pageStepCount;
        if ( wheelDelta < 0 )
            increment = -increment;
    }
    else
    {
        const int numSteps = wheelDelta / 120;
        increment = m_data->singleStep * numSteps;
    }
 
    if ( m_data->orientation == Qt::Vertical && m_data->inverted )
        increment = -increment;
 
    double value = boundedValue( m_data->value + increment );
 
    if ( m_data->stepAlignment )
        value = alignedValue( value );
 
    if ( value != m_data->value )
    {
        m_data->value = value;
        update();
 
        Q_EMIT valueChanged( m_data->value );
        Q_EMIT wheelMoved( m_data->value );
    }
}
 
void QwtWheel::keyPressEvent( QKeyEvent* event )
{
    if ( m_data->isScrolling )
    {
        // don't interfere mouse scrolling
        return;
    }
 
    double value = m_data->value;
    double increment = 0.0;
 
    switch ( event->key() )
    {
        case Qt::Key_Down:
        {
            if ( m_data->orientation == Qt::Vertical && m_data->inverted )
                increment = m_data->singleStep;
            else
                increment = -m_data->singleStep;
 
            break;
        }
        case Qt::Key_Up:
        {
            if ( m_data->orientation == Qt::Vertical && m_data->inverted )
                increment = -m_data->singleStep;
            else
                increment = m_data->singleStep;
 
            break;
        }
        case Qt::Key_Left:
        {
            if ( m_data->orientation == Qt::Horizontal )
            {
                if ( m_data->inverted )
                    increment = m_data->singleStep;
                else
                    increment = -m_data->singleStep;
            }
            break;
        }
        case Qt::Key_Right:
        {
            if ( m_data->orientation == Qt::Horizontal )
            {
                if ( m_data->inverted )
                    increment = -m_data->singleStep;
                else
                    increment = m_data->singleStep;
            }
            break;
        }
        case Qt::Key_PageUp:
        {
            increment = m_data->pageStepCount * m_data->singleStep;
            break;
        }
        case Qt::Key_PageDown:
        {
            increment = -m_data->pageStepCount * m_data->singleStep;
            break;
        }
        case Qt::Key_Home:
        {
            value = m_data->minimum;
            break;
        }
        case Qt::Key_End:
        {
            value = m_data->maximum;
            break;
        }
        default:;
            {
                event->ignore();
            }
    }
 
    if ( event->isAccepted() )
        stopFlying();
 
    if ( increment != 0.0 )
    {
        value = boundedValue( m_data->value + increment );
 
        if ( m_data->stepAlignment )
            value = alignedValue( value );
    }
 
    if ( value != m_data->value )
    {
        m_data->value = value;
        update();
 
        Q_EMIT valueChanged( m_data->value );
        Q_EMIT wheelMoved( m_data->value );
    }
}
 
void QwtWheel::setTickCount( int count )
{
    count = qBound( 6, count, 50 );
 
    if ( count != m_data->tickCount )
    {
        m_data->tickCount = qBound( 6, count, 50 );
        update();
    }
}
 
int QwtWheel::tickCount() const
{
    return m_data->tickCount;
}
 
void QwtWheel::setWheelBorderWidth( int borderWidth )
{
    const int d = qMin( width(), height() ) / 3;
    borderWidth = qMin( borderWidth, d );
    m_data->wheelBorderWidth = qMax( borderWidth, 1 );
    update();
}
 
int QwtWheel::wheelBorderWidth() const
{
    return m_data->wheelBorderWidth;
}
 
void QwtWheel::setBorderWidth( int width )
{
    m_data->borderWidth = qMax( width, 0 );
    update();
}
 
int QwtWheel::borderWidth() const
{
    return m_data->borderWidth;
}
 
QRect QwtWheel::wheelRect() const
{
    const int bw = m_data->borderWidth;
    return contentsRect().adjusted( bw, bw, -bw, -bw );
}
 
void QwtWheel::setTotalAngle( double angle )
{
    if ( angle < 0.0 )
        angle = 0.0;
 
    m_data->totalAngle = angle;
    update();
}
 
double QwtWheel::totalAngle() const
{
    return m_data->totalAngle;
}
 
void QwtWheel::setOrientation( Qt::Orientation orientation )
{
    if ( m_data->orientation == orientation )
        return;
 
    if ( !testAttribute( Qt::WA_WState_OwnSizePolicy ) )
    {
        QSizePolicy sp = sizePolicy();
        sp.transpose();
        setSizePolicy( sp );
 
        setAttribute( Qt::WA_WState_OwnSizePolicy, false );
    }
 
    m_data->orientation = orientation;
    update();
}
 
Qt::Orientation QwtWheel::orientation() const
{
    return m_data->orientation;
}
 
void QwtWheel::setViewAngle( double angle )
{
    m_data->viewAngle = qBound( 10.0, angle, 175.0 );
    update();
}
 
double QwtWheel::viewAngle() const
{
    return m_data->viewAngle;
}
 
double QwtWheel::valueAt( const QPoint& pos ) const
{
    const QRectF rect = wheelRect();
 
    double w, dx;
    if ( m_data->orientation == Qt::Vertical )
    {
        w = rect.height();
        dx = rect.top() - pos.y();
    }
    else
    {
        w = rect.width();
        dx = pos.x() - rect.left();
    }
 
    if ( w == 0.0 )
        return 0.0;
 
    if ( m_data->inverted )
    {
        dx = w - dx;
    }
 
    // w pixels is an arc of viewAngle degrees,
    // so we convert change in pixels to change in angle
    const double ang = dx * m_data->viewAngle / w;
 
    // value range maps to totalAngle degrees,
    // so convert the change in angle to a change in value
    const double val = ang * ( maximum() - minimum() ) / m_data->totalAngle;
 
    return val;
}
 
void QwtWheel::paintEvent( QPaintEvent* event )
{
    QPainter painter( this );
    painter.setClipRegion( event->region() );
 
    QStyleOption opt;
    opt.initFrom(this);
    style()->drawPrimitive(QStyle::PE_Widget, &opt, &painter, this);
 
    qDrawShadePanel( &painter,
        contentsRect(), palette(), true, m_data->borderWidth );
 
    drawWheelBackground( &painter, wheelRect() );
    drawTicks( &painter, wheelRect() );
 
    if ( hasFocus() )
        QwtPainter::drawFocusRect( &painter, this );
}
 
void QwtWheel::drawWheelBackground(
    QPainter* painter, const QRectF& rect )
{
    painter->save();
 
    QPalette pal = palette();
 
    //  draw shaded background
    QLinearGradient gradient( rect.topLeft(),
        ( m_data->orientation == Qt::Horizontal ) ? rect.topRight() : rect.bottomLeft() );
    gradient.setColorAt( 0.0, pal.color( QPalette::Button ) );
    gradient.setColorAt( 0.2, pal.color( QPalette::Midlight ) );
    gradient.setColorAt( 0.7, pal.color( QPalette::Mid ) );
    gradient.setColorAt( 1.0, pal.color( QPalette::Dark ) );
 
    painter->fillRect( rect, gradient );
 
    // draw internal border
 
    const QPen lightPen( palette().color( QPalette::Light ),
        m_data->wheelBorderWidth, Qt::SolidLine, Qt::FlatCap );
    const QPen darkPen( pal.color( QPalette::Dark ),
        m_data->wheelBorderWidth, Qt::SolidLine, Qt::FlatCap );
 
    const double bw2 = 0.5 * m_data->wheelBorderWidth;
 
    if ( m_data->orientation == Qt::Horizontal )
    {
        painter->setPen( lightPen );
        painter->drawLine( QPointF( rect.left(), rect.top() + bw2 ),
            QPointF( rect.right(), rect.top() + bw2 ) );
 
        painter->setPen( darkPen );
        painter->drawLine( QPointF( rect.left(), rect.bottom() - bw2 ),
            QPointF( rect.right(), rect.bottom() - bw2 ) );
    }
    else // Qt::Vertical
    {
        painter->setPen( lightPen );
        painter->drawLine( QPointF( rect.left() + bw2, rect.top() ),
            QPointF( rect.left() + bw2, rect.bottom() ) );
 
        painter->setPen( darkPen );
        painter->drawLine( QPointF( rect.right() - bw2, rect.top() ),
            QPointF( rect.right() - bw2, rect.bottom() ) );
    }
 
    painter->restore();
}
 
void QwtWheel::drawTicks( QPainter* painter, const QRectF& rect )
{
    const double range = m_data->maximum - m_data->minimum;
 
    if ( range == 0.0 || m_data->totalAngle == 0.0 )
    {
        return;
    }
 
    const QPen lightPen( palette().color( QPalette::Light ),
        0, Qt::SolidLine, Qt::FlatCap );
    const QPen darkPen( palette().color( QPalette::Dark ),
        0, Qt::SolidLine, Qt::FlatCap );
 
    const double cnvFactor = qAbs( m_data->totalAngle / range );
    const double halfIntv = 0.5 * m_data->viewAngle / cnvFactor;
    const double loValue = value() - halfIntv;
    const double hiValue = value() + halfIntv;
    const double tickWidth = 360.0 / double( m_data->tickCount ) / cnvFactor;
    const double sinArc = qFastSin( m_data->viewAngle * M_PI / 360.0 );
 
    if ( m_data->orientation == Qt::Horizontal )
    {
        const double radius = rect.width() * 0.5;
 
        double l1 = rect.top() + m_data->wheelBorderWidth;
        double l2 = rect.bottom() - m_data->wheelBorderWidth - 1;
 
        // draw one point over the border if border > 1
        if ( m_data->wheelBorderWidth > 1 )
        {
            l1--;
            l2++;
        }
 
        const double maxpos = rect.right() - 2;
        const double minpos = rect.left() + 2;
 
        // draw tick marks
        for ( double tickValue = std::ceil( loValue / tickWidth ) * tickWidth;
            tickValue < hiValue; tickValue += tickWidth )
        {
            const double angle = qwtRadians( tickValue - value() );
            const double s = qFastSin( angle * cnvFactor );
 
            const double off = radius * ( sinArc + s ) / sinArc;
 
            double tickPos;
            if ( m_data->inverted )
                tickPos = rect.left() + off;
            else
                tickPos = rect.right() - off;
 
            if ( ( tickPos <= maxpos ) && ( tickPos > minpos ) )
            {
                painter->setPen( darkPen );
                painter->drawLine( QPointF( tickPos - 1, l1 ),
                    QPointF( tickPos - 1,  l2 ) );
                painter->setPen( lightPen );
                painter->drawLine( QPointF( tickPos, l1 ),
                    QPointF( tickPos, l2 ) );
            }
        }
    }
    else // Qt::Vertical
    {
        const double radius = rect.height() * 0.5;
 
        double l1 = rect.left() + m_data->wheelBorderWidth;
        double l2 = rect.right() - m_data->wheelBorderWidth - 1;
 
        if ( m_data->wheelBorderWidth > 1 )
        {
            l1--;
            l2++;
        }
 
        const double maxpos = rect.bottom() - 2;
        const double minpos = rect.top() + 2;
 
        for ( double tickValue = std::ceil( loValue / tickWidth ) * tickWidth;
            tickValue < hiValue; tickValue += tickWidth )
        {
            const double angle = qwtRadians( tickValue - value() );
            const double s = qFastSin( angle * cnvFactor );
 
            const double off = radius * ( sinArc + s ) / sinArc;
 
            double tickPos;
 
            if ( m_data->inverted )
                tickPos = rect.bottom() - off;
            else
                tickPos = rect.top() + off;
 
            if ( ( tickPos <= maxpos ) && ( tickPos > minpos ) )
            {
                painter->setPen( darkPen );
                painter->drawLine( QPointF( l1, tickPos - 1 ),
                    QPointF( l2, tickPos - 1 ) );
                painter->setPen( lightPen );
                painter->drawLine( QPointF( l1, tickPos ),
                    QPointF( l2, tickPos ) );
            }
        }
    }
}
 
void QwtWheel::setWheelWidth( int width )
{
    m_data->wheelWidth = width;
    update();
}
 
int QwtWheel::wheelWidth() const
{
    return m_data->wheelWidth;
}
 
QSize QwtWheel::sizeHint() const
{
    const QSize hint = minimumSizeHint();
    return qwtExpandedToGlobalStrut( hint );
}
 
QSize QwtWheel::minimumSizeHint() const
{
    QSize sz( 3 * m_data->wheelWidth + 2 * m_data->borderWidth,
        m_data->wheelWidth + 2 * m_data->borderWidth );
    if ( m_data->orientation != Qt::Horizontal )
        sz.transpose();
 
    return sz;
}
 
void QwtWheel::setSingleStep( double stepSize )
{
    m_data->singleStep = qwtMaxF( stepSize, 0.0 );
}
 
double QwtWheel::singleStep() const
{
    return m_data->singleStep;
}
 
void QwtWheel::setStepAlignment( bool on )
{
    if ( on != m_data->stepAlignment )
    {
        m_data->stepAlignment = on;
    }
}
 
bool QwtWheel::stepAlignment() const
{
    return m_data->stepAlignment;
}
 
void QwtWheel::setPageStepCount( int count )
{
    m_data->pageStepCount = qMax( 0, count );
}
 
int QwtWheel::pageStepCount() const
{
    return m_data->pageStepCount;
}
 
void QwtWheel::setRange( double min, double max )
{
    max = qwtMaxF( min, max );
 
    if ( m_data->minimum == min && m_data->maximum == max )
        return;
 
    m_data->minimum = min;
    m_data->maximum = max;
 
    if ( m_data->value < min || m_data->value > max )
    {
        m_data->value = qBound( min, m_data->value, max );
 
        update();
        Q_EMIT valueChanged( m_data->value );
    }
}
void QwtWheel::setMinimum( double value )
{
    setRange( value, maximum() );
}
 
double QwtWheel::minimum() const
{
    return m_data->minimum;
}
 
void QwtWheel::setMaximum( double value )
{
    setRange( minimum(), value );
}
 
double QwtWheel::maximum() const
{
    return m_data->maximum;
}
 
void QwtWheel::setValue( double value )
{
    stopFlying();
    m_data->isScrolling = false;
 
    value = qBound( m_data->minimum, value, m_data->maximum );
 
    if ( m_data->value != value )
    {
        m_data->value = value;
 
        update();
        Q_EMIT valueChanged( m_data->value );
    }
}
 
double QwtWheel::value() const
{
    return m_data->value;
}
 
void QwtWheel::setInverted( bool on )
{
    if ( m_data->inverted != on )
    {
        m_data->inverted = on;
        update();
    }
}
 
bool QwtWheel::isInverted() const
{
    return m_data->inverted;
}
 
void QwtWheel::setWrapping( bool on )
{
    m_data->wrapping = on;
}
 
bool QwtWheel::wrapping() const
{
    return m_data->wrapping;
}
 
void QwtWheel::setMass( double mass )
{
    if ( mass < 0.001 )
    {
        m_data->mass = 0.0;
    }
    else
    {
        m_data->mass = qwtMinF( 100.0, mass );
    }
 
    if ( m_data->mass <= 0.0 )
        stopFlying();
}
 
double QwtWheel::mass() const
{
    return m_data->mass;
}
 
void QwtWheel::stopFlying()
{
    if ( m_data->timerId != 0 )
    {
        killTimer( m_data->timerId );
        m_data->timerId = 0;
        m_data->speed = 0.0;
    }
}
 
double QwtWheel::boundedValue( double value ) const
{
    const double range = m_data->maximum - m_data->minimum;
 
    if ( m_data->wrapping && range >= 0.0 )
    {
        if ( value < m_data->minimum )
        {
            value += std::ceil( ( m_data->minimum - value ) / range ) * range;
        }
        else if ( value > m_data->maximum )
        {
            value -= std::ceil( ( value - m_data->maximum ) / range ) * range;
        }
    }
    else
    {
        value = qBound( m_data->minimum, value, m_data->maximum );
    }
 
    return value;
}
 
double QwtWheel::alignedValue( double value ) const
{
    const double stepSize = m_data->singleStep;
 
    if ( stepSize > 0.0 )
    {
        value = m_data->minimum +
            qRound( ( value - m_data->minimum ) / 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, m_data->maximum ) )
            {
                // correct rounding error at the border
                value = m_data->maximum;
            }
        }
    }
 
    return value;
}
 
#if QWT_MOC_INCLUDE
#include "moc_qwt_wheel.cpp"
#endif