qwt_plot.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_plot.h"
#include "qwt_plot_dict.h"
#include "qwt_plot_layout.h"
#include "qwt_scale_widget.h"
#include "qwt_scale_engine.h"
#include "qwt_text_label.h"
#include "qwt_legend.h"
#include "qwt_legend_data.h"
#include "qwt_plot_canvas.h"
#include <qmath.h>
#include <qpainter.h>
#include <qpointer.h>
#include <qpaintengine.h>
#include <qapplication.h>
#include <qevent.h>

static inline void qwtEnableLegendItems( QwtPlot *plot, bool on )
{
    if ( on )
    {
        QObject::connect( 
            plot, SIGNAL( legendDataChanged(
                const QVariant &, const QList<QwtLegendData> & ) ),
            plot, SLOT( updateLegendItems( 
                const QVariant &, const QList<QwtLegendData> & ) ) );
    }
    else
    {
        QObject::disconnect( 
            plot, SIGNAL( legendDataChanged(
                const QVariant &, const QList<QwtLegendData> & ) ),
            plot, SLOT( updateLegendItems( 
                const QVariant &, const QList<QwtLegendData> & ) ) );
    }
}

static void qwtSetTabOrder( 
    QWidget *first, QWidget *second, bool withChildren )
{
    QList<QWidget *> tabChain;
    tabChain += first;
    tabChain += second;

    if ( withChildren )
    {
        QList<QWidget *> children = second->findChildren<QWidget *>();

        QWidget *w = second->nextInFocusChain();
        while ( children.contains( w ) )
        {
            children.removeAll( w );

            tabChain += w;
            w = w->nextInFocusChain();
        }
    }

    for ( int i = 0; i < tabChain.size() - 1; i++ )
    {
        QWidget *from = tabChain[i];
        QWidget *to = tabChain[i+1];

        const Qt::FocusPolicy policy1 = from->focusPolicy();
        const Qt::FocusPolicy policy2 = to->focusPolicy();

        QWidget *proxy1 = from->focusProxy();
        QWidget *proxy2 = to->focusProxy();

        from->setFocusPolicy( Qt::TabFocus );
        from->setFocusProxy( NULL);

        to->setFocusPolicy( Qt::TabFocus );
        to->setFocusProxy( NULL);

        QWidget::setTabOrder( from, to );

        from->setFocusPolicy( policy1 );
        from->setFocusProxy( proxy1);

        to->setFocusPolicy( policy2 );
        to->setFocusProxy( proxy2 );
    }
}

class QwtPlot::PrivateData
{
public:
    QPointer<QwtTextLabel> titleLabel;
    QPointer<QwtTextLabel> footerLabel;
    QPointer<QWidget> canvas;
    QPointer<QwtAbstractLegend> legend;
    QwtPlotLayout *layout;

    bool autoReplot;
};

QwtPlot::QwtPlot( QWidget *parent ):
    QFrame( parent )
{
    initPlot( QwtText() );
}

QwtPlot::QwtPlot( const QwtText &title, QWidget *parent ):
    QFrame( parent )
{
    initPlot( title );
}

QwtPlot::~QwtPlot()
{
    setAutoReplot( false );
    detachItems( QwtPlotItem::Rtti_PlotItem, autoDelete() );

    delete d_data->layout;
    deleteAxesData();
    delete d_data;
}

void QwtPlot::initPlot( const QwtText &title )
{
    d_data = new PrivateData;

    d_data->layout = new QwtPlotLayout;
    d_data->autoReplot = false;

    // title
    d_data->titleLabel = new QwtTextLabel( this );
    d_data->titleLabel->setObjectName( "QwtPlotTitle" );
    d_data->titleLabel->setFont( QFont( fontInfo().family(), 14, QFont::Bold ) );

    QwtText text( title );
    text.setRenderFlags( Qt::AlignCenter | Qt::TextWordWrap );
    d_data->titleLabel->setText( text );

    // footer
    d_data->footerLabel = new QwtTextLabel( this );
    d_data->footerLabel->setObjectName( "QwtPlotFooter" );

    QwtText footer;
    footer.setRenderFlags( Qt::AlignCenter | Qt::TextWordWrap );
    d_data->footerLabel->setText( footer );

    // legend
    d_data->legend = NULL;

    // axis
    initAxesData();

    // canvas
    d_data->canvas = new QwtPlotCanvas( this );
    d_data->canvas->setObjectName( "QwtPlotCanvas" );
    d_data->canvas->installEventFilter( this );

    setSizePolicy( QSizePolicy::MinimumExpanding,
        QSizePolicy::MinimumExpanding );

    resize( 200, 200 );

    QList<QWidget *> focusChain;
    focusChain << this << d_data->titleLabel << axisWidget( xTop )
        << axisWidget( yLeft ) << d_data->canvas << axisWidget( yRight )
        << axisWidget( xBottom ) << d_data->footerLabel;

    for ( int i = 0; i < focusChain.size() - 1; i++ )
        qwtSetTabOrder( focusChain[i], focusChain[i+1], false );

    qwtEnableLegendItems( this, true );
}

void QwtPlot::setCanvas( QWidget *canvas )
{
    if ( canvas == d_data->canvas )
        return;

    delete d_data->canvas;
    d_data->canvas = canvas;

    if ( canvas )
    {
        canvas->setParent( this );
        canvas->installEventFilter( this );

        if ( isVisible() )
            canvas->show();
    }
}

bool QwtPlot::event( QEvent *event )
{
    bool ok = QFrame::event( event );
    switch ( event->type() )
    {
        case QEvent::LayoutRequest:
            updateLayout();
            break;
        case QEvent::PolishRequest:
            replot();
            break;
        default:;
    }
    return ok;
}

bool QwtPlot::eventFilter( QObject *object, QEvent *event )
{
    if ( object == d_data->canvas )
    {
        if ( event->type() == QEvent::Resize )
        {
            updateCanvasMargins();
        }
        else if ( event->type() == QEvent::ContentsRectChange )
        {
            updateLayout();
        }
    }

    return QFrame::eventFilter( object, event );
}

void QwtPlot::autoRefresh()
{
    if ( d_data->autoReplot )
        replot();
}

void QwtPlot::setAutoReplot( bool tf )
{
    d_data->autoReplot = tf;
}

bool QwtPlot::autoReplot() const
{
    return d_data->autoReplot;
}

void QwtPlot::setTitle( const QString &title )
{
    if ( title != d_data->titleLabel->text().text() )
    {
        d_data->titleLabel->setText( title );
        updateLayout();
    }
}

void QwtPlot::setTitle( const QwtText &title )
{
    if ( title != d_data->titleLabel->text() )
    {
        d_data->titleLabel->setText( title );
        updateLayout();
    }
}

QwtText QwtPlot::title() const
{
    return d_data->titleLabel->text();
}

QwtTextLabel *QwtPlot::titleLabel()
{
    return d_data->titleLabel;
}

const QwtTextLabel *QwtPlot::titleLabel() const
{
    return d_data->titleLabel;
}

void QwtPlot::setFooter( const QString &text )
{
    if ( text != d_data->footerLabel->text().text() )
    {
        d_data->footerLabel->setText( text );
        updateLayout();
    }
}

void QwtPlot::setFooter( const QwtText &text )
{
    if ( text != d_data->footerLabel->text() )
    {
        d_data->footerLabel->setText( text );
        updateLayout();
    }
}

QwtText QwtPlot::footer() const
{
    return d_data->footerLabel->text();
}

QwtTextLabel *QwtPlot::footerLabel()
{
    return d_data->footerLabel;
}

const QwtTextLabel *QwtPlot::footerLabel() const
{
    return d_data->footerLabel;
}

void QwtPlot::setPlotLayout( QwtPlotLayout *layout )
{
    if ( layout != d_data->layout )
    {
        delete d_data->layout;
        d_data->layout = layout;

        updateLayout();
    }
}

QwtPlotLayout *QwtPlot::plotLayout()
{
    return d_data->layout;
}

const QwtPlotLayout *QwtPlot::plotLayout() const
{
    return d_data->layout;
}

QwtAbstractLegend *QwtPlot::legend()
{
    return d_data->legend;
}

const QwtAbstractLegend *QwtPlot::legend() const
{
    return d_data->legend;
}


QWidget *QwtPlot::canvas()
{
    return d_data->canvas;
}

const QWidget *QwtPlot::canvas() const
{
    return d_data->canvas;
}

QSize QwtPlot::sizeHint() const
{
    int dw = 0;
    int dh = 0;
    for ( int axisId = 0; axisId < axisCnt; axisId++ )
    {
        if ( axisEnabled( axisId ) )
        {
            const int niceDist = 40;
            const QwtScaleWidget *scaleWidget = axisWidget( axisId );
            const QwtScaleDiv &scaleDiv = scaleWidget->scaleDraw()->scaleDiv();
            const int majCnt = scaleDiv.ticks( QwtScaleDiv::MajorTick ).count();

            if ( axisId == yLeft || axisId == yRight )
            {
                int hDiff = ( majCnt - 1 ) * niceDist
                    - scaleWidget->minimumSizeHint().height();
                if ( hDiff > dh )
                    dh = hDiff;
            }
            else
            {
                int wDiff = ( majCnt - 1 ) * niceDist
                    - scaleWidget->minimumSizeHint().width();
                if ( wDiff > dw )
                    dw = wDiff;
            }
        }
    }
    return minimumSizeHint() + QSize( dw, dh );
}

QSize QwtPlot::minimumSizeHint() const
{
    QSize hint = d_data->layout->minimumSizeHint( this );
    hint += QSize( 2 * frameWidth(), 2 * frameWidth() );

    return hint;
}

void QwtPlot::resizeEvent( QResizeEvent *e )
{
    QFrame::resizeEvent( e );
    updateLayout();
}

void QwtPlot::replot()
{
    bool doAutoReplot = autoReplot();
    setAutoReplot( false );

    updateAxes();

    /*
      Maybe the layout needs to be updated, because of changed
      axes labels. We need to process them here before painting
      to avoid that scales and canvas get out of sync.
     */
    QApplication::sendPostedEvents( this, QEvent::LayoutRequest );

    if ( d_data->canvas )
    {
        const bool ok = QMetaObject::invokeMethod( 
            d_data->canvas, "replot", Qt::DirectConnection );
        if ( !ok )
        {
            // fallback, when canvas has no a replot method
            d_data->canvas->update( d_data->canvas->contentsRect() );
        }
    }

    setAutoReplot( doAutoReplot );
}

void QwtPlot::updateLayout()
{
    d_data->layout->activate( this, contentsRect() );

    QRect titleRect = d_data->layout->titleRect().toRect();
    QRect footerRect = d_data->layout->footerRect().toRect();
    QRect scaleRect[QwtPlot::axisCnt];
    for ( int axisId = 0; axisId < axisCnt; axisId++ )
        scaleRect[axisId] = d_data->layout->scaleRect( axisId ).toRect();
    QRect legendRect = d_data->layout->legendRect().toRect();
    QRect canvasRect = d_data->layout->canvasRect().toRect();

    // resize and show the visible widgets

    if ( !d_data->titleLabel->text().isEmpty() )
    {
        d_data->titleLabel->setGeometry( titleRect );
        if ( !d_data->titleLabel->isVisibleTo( this ) )
            d_data->titleLabel->show();
    }
    else
        d_data->titleLabel->hide();

    if ( !d_data->footerLabel->text().isEmpty() )
    {
        d_data->footerLabel->setGeometry( footerRect );
        if ( !d_data->footerLabel->isVisibleTo( this ) )
            d_data->footerLabel->show();
    }
    else
    {
        d_data->footerLabel->hide();
    }

    for ( int axisId = 0; axisId < axisCnt; axisId++ )
    {
        QwtScaleWidget* scaleWidget = axisWidget( axisId );

        if ( axisEnabled( axisId ) )
        {
            if ( scaleRect[axisId] != scaleWidget->geometry() )
            {
                scaleWidget->setGeometry( scaleRect[axisId] );

                int startDist, endDist;
                scaleWidget->getBorderDistHint( startDist, endDist );
                scaleWidget->setBorderDist( startDist, endDist );
            }

            if ( !scaleWidget->isVisibleTo( this ) )
                scaleWidget->show();
        }
        else
        {
            scaleWidget->hide();
        }
    }

    if ( d_data->legend )
    {
        if ( d_data->legend->isEmpty() )
        {
            d_data->legend->hide();
        }
        else
        {
            d_data->legend->setGeometry( legendRect );
            d_data->legend->show();
        }
    }

    d_data->canvas->setGeometry( canvasRect );
}

void QwtPlot::getCanvasMarginsHint(
    const QwtScaleMap maps[], const QRectF &canvasRect,
    double &left, double &top, double &right, double &bottom) const
{
    left = top = right = bottom = -1.0;

    const QwtPlotItemList& itmList = itemList();
    for ( QwtPlotItemIterator it = itmList.begin();
        it != itmList.end(); ++it )
    {
        const QwtPlotItem *item = *it;
        if ( item->testItemAttribute( QwtPlotItem::Margins ) )
        {
            double m[ QwtPlot::axisCnt ];
            item->getCanvasMarginHint(
                maps[ item->xAxis() ], maps[ item->yAxis() ],
                canvasRect, m[yLeft], m[xTop], m[yRight], m[xBottom] );

            left = qMax( left, m[yLeft] );
            top = qMax( top, m[xTop] );
            right = qMax( right, m[yRight] );
            bottom = qMax( bottom, m[xBottom] );
        }
    }
}

void QwtPlot::updateCanvasMargins()
{
    QwtScaleMap maps[axisCnt];
    for ( int axisId = 0; axisId < axisCnt; axisId++ )
        maps[axisId] = canvasMap( axisId );

    double margins[axisCnt];
    getCanvasMarginsHint( maps, canvas()->contentsRect(),
        margins[yLeft], margins[xTop], margins[yRight], margins[xBottom] );
    
    bool doUpdate = false;
    for ( int axisId = 0; axisId < axisCnt; axisId++ )
    {
        if ( margins[axisId] >= 0.0 )
        {
            const int m = qCeil( margins[axisId] );
            plotLayout()->setCanvasMargin( m, axisId);
            doUpdate = true;
        }
    }

    if ( doUpdate )
        updateLayout();
}

void QwtPlot::drawCanvas( QPainter *painter )
{
    QwtScaleMap maps[axisCnt];
    for ( int axisId = 0; axisId < axisCnt; axisId++ )
        maps[axisId] = canvasMap( axisId );

    drawItems( painter, d_data->canvas->contentsRect(), maps );
}

void QwtPlot::drawItems( QPainter *painter, const QRectF &canvasRect,
        const QwtScaleMap maps[axisCnt] ) const
{
    const QwtPlotItemList& itmList = itemList();
    for ( QwtPlotItemIterator it = itmList.begin();
        it != itmList.end(); ++it )
    {
        QwtPlotItem *item = *it;
        if ( item && item->isVisible() )
        {
            painter->save();

            painter->setRenderHint( QPainter::Antialiasing,
                item->testRenderHint( QwtPlotItem::RenderAntialiased ) );
            painter->setRenderHint( QPainter::HighQualityAntialiasing,
                item->testRenderHint( QwtPlotItem::RenderAntialiased ) );

            item->draw( painter,
                maps[item->xAxis()], maps[item->yAxis()],
                canvasRect );

            painter->restore();
        }
    }
}

QwtScaleMap QwtPlot::canvasMap( int axisId ) const
{
    QwtScaleMap map;
    if ( !d_data->canvas )
        return map;

    map.setTransformation( axisScaleEngine( axisId )->transformation() );

    const QwtScaleDiv &sd = axisScaleDiv( axisId );
    map.setScaleInterval( sd.lowerBound(), sd.upperBound() );

    if ( axisEnabled( axisId ) )
    {
        const QwtScaleWidget *s = axisWidget( axisId );
        if ( axisId == yLeft || axisId == yRight )
        {
            double y = s->y() + s->startBorderDist() - d_data->canvas->y();
            double h = s->height() - s->startBorderDist() - s->endBorderDist();
            map.setPaintInterval( y + h, y );
        }
        else
        {
            double x = s->x() + s->startBorderDist() - d_data->canvas->x();
            double w = s->width() - s->startBorderDist() - s->endBorderDist();
            map.setPaintInterval( x, x + w );
        }
    }
    else
    {
        const QRect &canvasRect = d_data->canvas->contentsRect();
        if ( axisId == yLeft || axisId == yRight )
        {
            int top = 0;
            if ( !plotLayout()->alignCanvasToScale( xTop ) )
                top = plotLayout()->canvasMargin( xTop );

            int bottom = 0;
            if ( !plotLayout()->alignCanvasToScale( xBottom ) )
                bottom = plotLayout()->canvasMargin( xBottom );

            map.setPaintInterval( canvasRect.bottom() - bottom,
                canvasRect.top() + top );
        }
        else
        {
            int left = 0;
            if ( !plotLayout()->alignCanvasToScale( yLeft ) )
                left = plotLayout()->canvasMargin( yLeft );

            int right = 0;
            if ( !plotLayout()->alignCanvasToScale( yRight ) )
                right = plotLayout()->canvasMargin( yRight );

            map.setPaintInterval( canvasRect.left() + left,
                canvasRect.right() - right );
        }
    }

    return map;
}

void QwtPlot::setCanvasBackground( const QBrush &brush )
{
    QPalette pal = d_data->canvas->palette();
    pal.setBrush( QPalette::Window, brush );

    canvas()->setPalette( pal );
}

QBrush QwtPlot::canvasBackground() const
{
    return canvas()->palette().brush(
        QPalette::Normal, QPalette::Window );
}

bool QwtPlot::axisValid( int axisId )
{
    return ( ( axisId >= QwtPlot::yLeft ) && ( axisId < QwtPlot::axisCnt ) );
}

void QwtPlot::insertLegend( QwtAbstractLegend *legend,
    QwtPlot::LegendPosition pos, double ratio )
{
    d_data->layout->setLegendPosition( pos, ratio );

    if ( legend != d_data->legend )
    {
        if ( d_data->legend && d_data->legend->parent() == this )
            delete d_data->legend;

        d_data->legend = legend;

        if ( d_data->legend )
        {
            connect( this, 
                SIGNAL( legendDataChanged( 
                    const QVariant &, const QList<QwtLegendData> & ) ),
                d_data->legend, 
                SLOT( updateLegend( 
                    const QVariant &, const QList<QwtLegendData> & ) ) 
            );

            if ( d_data->legend->parent() != this )
                d_data->legend->setParent( this );

            qwtEnableLegendItems( this, false );
            updateLegend();
            qwtEnableLegendItems( this, true );

            QwtLegend *lgd = qobject_cast<QwtLegend *>( legend );
            if ( lgd )
            {
                switch ( d_data->layout->legendPosition() )
                {
                    case LeftLegend:
                    case RightLegend:
                    {
                        if ( lgd->maxColumns() == 0     )
                            lgd->setMaxColumns( 1 ); // 1 column: align vertical
                        break;
                    }
                    case TopLegend:
                    case BottomLegend:
                    {
                        lgd->setMaxColumns( 0 ); // unlimited
                        break;
                    }
                    default:
                        break;
                }
            }

            QWidget *previousInChain = NULL;
            switch ( d_data->layout->legendPosition() )
            {
                case LeftLegend:
                {
                    previousInChain = axisWidget( QwtPlot::xTop );
                    break;
                }
                case TopLegend:
                {
                    previousInChain = this;
                    break;
                }
                case RightLegend:
                {
                    previousInChain = axisWidget( QwtPlot::yRight );
                    break;
                }
                case BottomLegend:
                {
                    previousInChain = footerLabel();
                    break;
                }
            }

            if ( previousInChain )
                qwtSetTabOrder( previousInChain, legend, true );
        }
    }

    updateLayout();
}

void QwtPlot::updateLegend()
{
    const QwtPlotItemList& itmList = itemList();
    for ( QwtPlotItemIterator it = itmList.begin();
        it != itmList.end(); ++it )
    {
        updateLegend( *it );
    }
}

void QwtPlot::updateLegend( const QwtPlotItem *plotItem )
{
    if ( plotItem == NULL )
        return;

    QList<QwtLegendData> legendData;

    if ( plotItem->testItemAttribute( QwtPlotItem::Legend ) )
        legendData = plotItem->legendData();

    const QVariant itemInfo = itemToInfo( const_cast< QwtPlotItem *>( plotItem) );
    Q_EMIT legendDataChanged( itemInfo, legendData );
}

void QwtPlot::updateLegendItems( const QVariant &itemInfo,
    const QList<QwtLegendData> &legendData )
{
    QwtPlotItem *plotItem = infoToItem( itemInfo );
    if ( plotItem )
    {
        const QwtPlotItemList& itmList = itemList();
        for ( QwtPlotItemIterator it = itmList.begin();
            it != itmList.end(); ++it )
        {
            QwtPlotItem *item = *it;
            if ( item->testItemInterest( QwtPlotItem::LegendInterest ) )
                item->updateLegend( plotItem, legendData );
        }
    }
}

void QwtPlot::attachItem( QwtPlotItem *plotItem, bool on )
{
    if ( plotItem->testItemInterest( QwtPlotItem::LegendInterest ) )
    {
        // plotItem is some sort of legend

        const QwtPlotItemList& itmList = itemList();
        for ( QwtPlotItemIterator it = itmList.begin();
            it != itmList.end(); ++it )
        {
            QwtPlotItem *item = *it;

            QList<QwtLegendData> legendData;
            if ( on && item->testItemAttribute( QwtPlotItem::Legend ) )
            {
                legendData = item->legendData();
                plotItem->updateLegend( item, legendData );
            }
        }
    }

    if ( on )
        insertItem( plotItem );
    else 
        removeItem( plotItem );

    Q_EMIT itemAttached( plotItem, on );

    if ( plotItem->testItemAttribute( QwtPlotItem::Legend ) )
    {
        // the item wants to be represented on the legend

        if ( on )
        {
            updateLegend( plotItem );
        }
        else
        {
            const QVariant itemInfo = itemToInfo( plotItem );
            Q_EMIT legendDataChanged( itemInfo, QList<QwtLegendData>() );
        }
    }

    autoRefresh();
}

QVariant QwtPlot::itemToInfo( QwtPlotItem *plotItem ) const
{
    QVariant itemInfo;
    qVariantSetValue( itemInfo, plotItem );

    return itemInfo;
}

QwtPlotItem *QwtPlot::infoToItem( const QVariant &itemInfo ) const
{
    if ( itemInfo.canConvert<QwtPlotItem *>() )
        return qvariant_cast<QwtPlotItem *>( itemInfo );

    return NULL;
}