qwt_plot_rescaler.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_plot_rescaler.h"
#include "qwt_plot.h"
#include "qwt_scale_div.h"
#include "qwt_interval.h"
#include "qwt_plot_canvas.h"

#include <qevent.h>

class QwtPlotRescaler::AxisData
{
  public:
    AxisData()
        : aspectRatio( 1.0 )
        , expandingDirection( QwtPlotRescaler::ExpandUp )
    {
    }

    double aspectRatio;
    QwtInterval intervalHint;
    QwtPlotRescaler::ExpandingDirection expandingDirection;
    mutable QwtScaleDiv scaleDiv;
};

class QwtPlotRescaler::PrivateData
{
  public:
    PrivateData()
        : referenceAxis( QwtAxis::XBottom )
        , rescalePolicy( QwtPlotRescaler::Expanding )
        , isEnabled( false )
        , inReplot( 0 )
    {
    }

    QwtPlotRescaler::AxisData* axisData( QwtAxisId axisId )
    {
        if ( !QwtAxis::isValid( axisId ) )
            return NULL;

        return &m_axisData[ axisId];
    }

    QwtAxisId referenceAxis;
    RescalePolicy rescalePolicy;
    bool isEnabled;

    mutable int inReplot;

  private:
    QwtPlotRescaler::AxisData m_axisData[QwtAxis::AxisPositions];
};

QwtPlotRescaler::QwtPlotRescaler( QWidget* canvas,
        QwtAxisId referenceAxis, RescalePolicy policy )
    : QObject( canvas )
{
    m_data = new PrivateData;
    m_data->referenceAxis = referenceAxis;
    m_data->rescalePolicy = policy;

    setEnabled( true );
}

QwtPlotRescaler::~QwtPlotRescaler()
{
    delete m_data;
}

void QwtPlotRescaler::setEnabled( bool on )
{
    if ( m_data->isEnabled != on )
    {
        m_data->isEnabled = on;

        QWidget* w = canvas();
        if ( w )
        {
            if ( m_data->isEnabled )
                w->installEventFilter( this );
            else
                w->removeEventFilter( this );
        }
    }
}

bool QwtPlotRescaler::isEnabled() const
{
    return m_data->isEnabled;
}

void QwtPlotRescaler::setRescalePolicy( RescalePolicy policy )
{
    m_data->rescalePolicy = policy;
}

QwtPlotRescaler::RescalePolicy QwtPlotRescaler::rescalePolicy() const
{
    return m_data->rescalePolicy;
}

void QwtPlotRescaler::setReferenceAxis( QwtAxisId axisId )
{
    m_data->referenceAxis = axisId;
}

QwtAxisId QwtPlotRescaler::referenceAxis() const
{
    return m_data->referenceAxis;
}

void QwtPlotRescaler::setExpandingDirection(
    ExpandingDirection direction )
{
    for ( int axis = 0; axis < QwtAxis::AxisPositions; axis++ )
        setExpandingDirection( axis, direction );
}

void QwtPlotRescaler::setExpandingDirection(
    QwtAxisId axisId, ExpandingDirection direction )
{
    if ( AxisData* axisData = m_data->axisData( axisId ) )
        axisData->expandingDirection = direction;
}

QwtPlotRescaler::ExpandingDirection
QwtPlotRescaler::expandingDirection( QwtAxisId axisId ) const
{
    if ( const AxisData* axisData = m_data->axisData( axisId ) )
        return axisData->expandingDirection;

    return ExpandBoth;
}

void QwtPlotRescaler::setAspectRatio( double ratio )
{
    for ( int axis = 0; axis < QwtAxis::AxisPositions; axis++ )
        setAspectRatio( axis, ratio );
}

void QwtPlotRescaler::setAspectRatio( QwtAxisId axisId, double ratio )
{
    if ( AxisData* axisData = m_data->axisData( axisId ) )
    {
        if ( ratio < 0.0 )
            ratio = 0.0;

        axisData->aspectRatio = ratio;
    }
}

double QwtPlotRescaler::aspectRatio( QwtAxisId axisId ) const
{
    if ( AxisData* axisData = m_data->axisData( axisId ) )
        return axisData->aspectRatio;

    return 0.0;
}

void QwtPlotRescaler::setIntervalHint( QwtAxisId axisId,
    const QwtInterval& interval )
{
    if ( AxisData* axisData = m_data->axisData( axisId ) )
        axisData->intervalHint = interval;
}

QwtInterval QwtPlotRescaler::intervalHint( QwtAxisId axisId ) const
{
    if ( AxisData* axisData = m_data->axisData( axisId ) )
        return axisData->intervalHint;

    return QwtInterval();
}

QWidget* QwtPlotRescaler::canvas()
{
    return qobject_cast< QWidget* >( parent() );
}

const QWidget* QwtPlotRescaler::canvas() const
{
    return qobject_cast< const QWidget* >( parent() );
}

QwtPlot* QwtPlotRescaler::plot()
{
    QWidget* w = canvas();
    if ( w )
        w = w->parentWidget();

    return qobject_cast< QwtPlot* >( w );
}

const QwtPlot* QwtPlotRescaler::plot() const
{
    const QWidget* w = canvas();
    if ( w )
        w = w->parentWidget();

    return qobject_cast< const QwtPlot* >( w );
}

bool QwtPlotRescaler::eventFilter( QObject* object, QEvent* event )
{
    if ( object && object == canvas() )
    {
        switch ( event->type() )
        {
            case QEvent::Resize:
            {
                canvasResizeEvent( static_cast< QResizeEvent* >( event ) );
                break;
            }
            case QEvent::PolishRequest:
            {
                rescale();
                break;
            }
            default:;
        }
    }

    return false;
}

void QwtPlotRescaler::canvasResizeEvent( QResizeEvent* event )
{
    const QMargins m = canvas()->contentsMargins();
    const QSize marginSize( m.left() + m.right(), m.top() + m.bottom() );

    const QSize newSize = event->size() - marginSize;
    const QSize oldSize = event->oldSize() - marginSize;

    rescale( oldSize, newSize );
}

void QwtPlotRescaler::rescale() const
{
    const QSize size = canvas()->contentsRect().size();
    rescale( size, size );
}

void QwtPlotRescaler::rescale(
    const QSize& oldSize, const QSize& newSize ) const
{
    if ( newSize.isEmpty() )
        return;

    QwtInterval intervals[QwtAxis::AxisPositions];
    for ( int axisPos = 0; axisPos < QwtAxis::AxisPositions; axisPos++ )
    {
        const QwtAxisId axisId( axisPos );
        intervals[axisPos] = interval( axisId );
    }

    const QwtAxisId refAxis = referenceAxis();
    intervals[refAxis] = expandScale( refAxis, oldSize, newSize );

    for ( int axisPos = 0; axisPos < QwtAxis::AxisPositions; axisPos++ )
    {
        const QwtAxisId axisId( axisPos );
        if ( aspectRatio( axisId ) > 0.0 && axisId != refAxis )
        {
            intervals[axisPos] = syncScale(
                axisId, intervals[refAxis], newSize );
        }
    }

    updateScales( intervals );
}

QwtInterval QwtPlotRescaler::expandScale( QwtAxisId axisId,
    const QSize& oldSize, const QSize& newSize ) const
{
    const QwtInterval oldInterval = interval( axisId );

    QwtInterval expanded = oldInterval;
    switch ( rescalePolicy() )
    {
        case Fixed:
        {
            break; // do nothing
        }
        case Expanding:
        {
            if ( !oldSize.isEmpty() )
            {
                double width = oldInterval.width();
                if ( orientation( axisId ) == Qt::Horizontal )
                    width *= double( newSize.width() ) / oldSize.width();
                else
                    width *= double( newSize.height() ) / oldSize.height();

                expanded = expandInterval( oldInterval,
                    width, expandingDirection( axisId ) );
            }
            break;
        }
        case Fitting:
        {
            double dist = 0.0;
            for ( int axisPos = 0; axisPos < QwtAxis::AxisPositions; axisPos++ )
            {
                const QwtAxisId axisId( axisPos );
                const double d = pixelDist( axisId, newSize );
                if ( d > dist )
                    dist = d;
            }
            if ( dist > 0.0 )
            {
                double width;
                if ( orientation( axisId ) == Qt::Horizontal )
                    width = newSize.width() * dist;
                else
                    width = newSize.height() * dist;

                expanded = expandInterval( intervalHint( axisId ),
                    width, expandingDirection( axisId ) );
            }
            break;
        }
    }

    return expanded;
}

QwtInterval QwtPlotRescaler::syncScale( QwtAxisId axisId,
    const QwtInterval& reference, const QSize& size ) const
{
    double dist;
    if ( orientation( referenceAxis() ) == Qt::Horizontal )
        dist = reference.width() / size.width();
    else
        dist = reference.width() / size.height();

    if ( orientation( axisId ) == Qt::Horizontal )
        dist *= size.width();
    else
        dist *= size.height();

    dist /= aspectRatio( axisId );

    QwtInterval intv;
    if ( rescalePolicy() == Fitting )
        intv = intervalHint( axisId );
    else
        intv = interval( axisId );

    intv = expandInterval( intv, dist, expandingDirection( axisId ) );

    return intv;
}

Qt::Orientation QwtPlotRescaler::orientation( QwtAxisId axisId ) const
{
    return QwtAxis::isYAxis( axisId ) ? Qt::Vertical : Qt::Horizontal;
}

QwtInterval QwtPlotRescaler::interval( QwtAxisId axisId ) const
{
    if ( !plot()->isAxisValid( axisId ) )
        return QwtInterval();

    return plot()->axisScaleDiv( axisId ).interval().normalized();
}

QwtInterval QwtPlotRescaler::expandInterval(
    const QwtInterval& interval, double width,
    ExpandingDirection direction ) const
{
    QwtInterval expanded = interval;

    switch ( direction )
    {
        case ExpandUp:
            expanded.setMinValue( interval.minValue() );
            expanded.setMaxValue( interval.minValue() + width );
            break;

        case ExpandDown:
            expanded.setMaxValue( interval.maxValue() );
            expanded.setMinValue( interval.maxValue() - width );
            break;

        case ExpandBoth:
        default:
            expanded.setMinValue( interval.minValue() +
                interval.width() / 2.0 - width / 2.0 );
            expanded.setMaxValue( expanded.minValue() + width );
    }
    return expanded;
}

double QwtPlotRescaler::pixelDist( QwtAxisId axisId, const QSize& size ) const
{
    const QwtInterval intv = intervalHint( axisId );

    double dist = 0.0;
    if ( !intv.isNull() )
    {
        if ( axisId == referenceAxis() )
        {
            dist = intv.width();
        }
        else
        {
            const double r = aspectRatio( axisId );
            if ( r > 0.0 )
                dist = intv.width() * r;
        }
    }

    if ( dist > 0.0 )
    {
        if ( orientation( axisId ) == Qt::Horizontal )
            dist /= size.width();
        else
            dist /= size.height();
    }

    return dist;
}

void QwtPlotRescaler::updateScales(
    QwtInterval intervals[QwtAxis::AxisPositions] ) const
{
    if ( m_data->inReplot >= 5 )
    {
        return;
    }

    QwtPlot* plt = const_cast< QwtPlot* >( plot() );

    const bool doReplot = plt->autoReplot();
    plt->setAutoReplot( false );

    for ( int axisPos = 0; axisPos < QwtAxis::AxisPositions; axisPos++ )
    {
        {
            const QwtAxisId axisId( axisPos );

            if ( axisId == referenceAxis() || aspectRatio( axisId ) > 0.0 )
            {
                double v1 = intervals[axisPos].minValue();
                double v2 = intervals[axisPos].maxValue();

                if ( !plt->axisScaleDiv( axisId ).isIncreasing() )
                    qSwap( v1, v2 );

                if ( m_data->inReplot >= 1 )
                    m_data->axisData( axisId )->scaleDiv = plt->axisScaleDiv( axisId );

                if ( m_data->inReplot >= 2 )
                {
                    QList< double > ticks[QwtScaleDiv::NTickTypes];
                    for ( int t = 0; t < QwtScaleDiv::NTickTypes; t++ )
                        ticks[t] = m_data->axisData( axisId )->scaleDiv.ticks( t );

                    plt->setAxisScaleDiv( axisId, QwtScaleDiv( v1, v2, ticks ) );
                }
                else
                {
                    plt->setAxisScale( axisId, v1, v2 );
                }
            }
        }
    }

    QwtPlotCanvas* canvas = qobject_cast< QwtPlotCanvas* >( plt->canvas() );

    bool immediatePaint = false;
    if ( canvas )
    {
        immediatePaint = canvas->testPaintAttribute( QwtPlotCanvas::ImmediatePaint );
        canvas->setPaintAttribute( QwtPlotCanvas::ImmediatePaint, false );
    }

    plt->setAutoReplot( doReplot );

    m_data->inReplot++;
    plt->replot();
    m_data->inReplot--;

    if ( canvas && immediatePaint )
    {
        canvas->setPaintAttribute( QwtPlotCanvas::ImmediatePaint, true );
    }
}

#if QWT_MOC_INCLUDE
#include "moc_qwt_plot_rescaler.cpp"
#endif