qwt_plot_histogram.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_histogram.h"
#include "qwt_painter.h"
#include "qwt_column_symbol.h"
#include "qwt_scale_map.h"
#include "qwt_graphic.h"

#include <qstring.h>
#include <qpainter.h>

static inline bool qwtIsCombinable( const QwtInterval &d1,
    const QwtInterval &d2 )
{
    if ( d1.isValid() && d2.isValid() )
    {
        if ( d1.maxValue() == d2.minValue() )
        {
            if ( !( d1.borderFlags() & QwtInterval::ExcludeMaximum
                && d2.borderFlags() & QwtInterval::ExcludeMinimum ) )
            {
                return true;
            }
        }
    }

    return false;
}

class QwtPlotHistogram::PrivateData
{
public:
    PrivateData():
        baseline( 0.0 ),
        style( Columns ),
        symbol( NULL )
    {
    }

    ~PrivateData()
    {
        delete symbol;
    }

    double baseline;

    QPen pen;
    QBrush brush;
    QwtPlotHistogram::HistogramStyle style;
    const QwtColumnSymbol *symbol;
};

QwtPlotHistogram::QwtPlotHistogram( const QwtText &title ):
    QwtPlotSeriesItem( title )
{
    init();
}

QwtPlotHistogram::QwtPlotHistogram( const QString &title ):
    QwtPlotSeriesItem( title )
{
    init();
}

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

void QwtPlotHistogram::init()
{
    d_data = new PrivateData();
    setData( new QwtIntervalSeriesData() );

    setItemAttribute( QwtPlotItem::AutoScale, true );
    setItemAttribute( QwtPlotItem::Legend, true );

    setZ( 20.0 );
}

void QwtPlotHistogram::setStyle( HistogramStyle style )
{
    if ( style != d_data->style )
    {
        d_data->style = style;

        legendChanged();
        itemChanged();
    }
}

QwtPlotHistogram::HistogramStyle QwtPlotHistogram::style() const
{
    return d_data->style;
}

void QwtPlotHistogram::setPen( const QColor &color, qreal width, Qt::PenStyle style )
{
    setPen( QPen( color, width, style ) );
}

void QwtPlotHistogram::setPen( const QPen &pen )
{
    if ( pen != d_data->pen )
    {
        d_data->pen = pen;

        legendChanged();
        itemChanged();
    }
}

const QPen &QwtPlotHistogram::pen() const
{
    return d_data->pen;
}

void QwtPlotHistogram::setBrush( const QBrush &brush )
{
    if ( brush != d_data->brush )
    {
        d_data->brush = brush;

        legendChanged();
        itemChanged();
    }
}

const QBrush &QwtPlotHistogram::brush() const
{
    return d_data->brush;
}

void QwtPlotHistogram::setSymbol( const QwtColumnSymbol *symbol )
{
    if ( symbol != d_data->symbol )
    {
        delete d_data->symbol;
        d_data->symbol = symbol;

        legendChanged();
        itemChanged();
    }
}

const QwtColumnSymbol *QwtPlotHistogram::symbol() const
{
    return d_data->symbol;
}

void QwtPlotHistogram::setBaseline( double value )
{
    if ( d_data->baseline != value )
    {
        d_data->baseline = value;
        itemChanged();
    }
}

double QwtPlotHistogram::baseline() const
{
    return d_data->baseline;
}

QRectF QwtPlotHistogram::boundingRect() const
{
    QRectF rect = data()->boundingRect();
    if ( !rect.isValid() )
        return rect;

    if ( orientation() == Qt::Horizontal )
    {
        rect = QRectF( rect.y(), rect.x(),
            rect.height(), rect.width() );

        if ( rect.left() > d_data->baseline )
            rect.setLeft( d_data->baseline );
        else if ( rect.right() < d_data->baseline )
            rect.setRight( d_data->baseline );
    }
    else
    {
        if ( rect.bottom() < d_data->baseline )
            rect.setBottom( d_data->baseline );
        else if ( rect.top() > d_data->baseline )
            rect.setTop( d_data->baseline );
    }

    return rect;
}

int QwtPlotHistogram::rtti() const
{
    return QwtPlotItem::Rtti_PlotHistogram;
}

void QwtPlotHistogram::setSamples(
    const QVector<QwtIntervalSample> &samples )
{
    setData( new QwtIntervalSeriesData( samples ) );
}

void QwtPlotHistogram::setSamples(
    QwtSeriesData<QwtIntervalSample> *data )
{
    setData( data );
}

void QwtPlotHistogram::drawSeries( QPainter *painter,
    const QwtScaleMap &xMap, const QwtScaleMap &yMap,
    const QRectF &canvasRect, int from, int to ) const
{
    Q_UNUSED( canvasRect )

    if ( !painter || dataSize() <= 0 )
        return;

    if ( to < 0 )
        to = dataSize() - 1;

    switch ( d_data->style )
    {
        case Outline:
            drawOutline( painter, xMap, yMap, from, to );
            break;
        case Lines:
            drawLines( painter, xMap, yMap, from, to );
            break;
        case Columns:
            drawColumns( painter, xMap, yMap, from, to );
            break;
        default:
            break;
    }
}

void QwtPlotHistogram::drawOutline( QPainter *painter,
    const QwtScaleMap &xMap, const QwtScaleMap &yMap,
    int from, int to ) const
{
    const bool doAlign = QwtPainter::roundingAlignment( painter );

    double v0 = ( orientation() == Qt::Horizontal ) ?
        xMap.transform( baseline() ) : yMap.transform( baseline() );
    if ( doAlign )
        v0 = qRound( v0 );

    QwtIntervalSample previous;

    QPolygonF polygon;
    for ( int i = from; i <= to; i++ )
    {
        const QwtIntervalSample sample = this->sample( i );

        if ( !sample.interval.isValid() )
        {
            flushPolygon( painter, v0, polygon );
            previous = sample;
            continue;
        }

        if ( previous.interval.isValid() )
        {
            if ( !qwtIsCombinable( previous.interval, sample.interval ) )
                flushPolygon( painter, v0, polygon );
        }

        if ( orientation() == Qt::Vertical )
        {
            double x1 = xMap.transform( sample.interval.minValue() );
            double x2 = xMap.transform( sample.interval.maxValue() );
            double y = yMap.transform( sample.value );
            if ( doAlign )
            {
                x1 = qRound( x1 );
                x2 = qRound( x2 );
                y = qRound( y );
            }

            if ( polygon.size() == 0 )
                polygon += QPointF( x1, v0 );

            polygon += QPointF( x1, y );
            polygon += QPointF( x2, y );
        }
        else
        {
            double y1 = yMap.transform( sample.interval.minValue() );
            double y2 = yMap.transform( sample.interval.maxValue() );
            double x = xMap.transform( sample.value );
            if ( doAlign )
            {
                y1 = qRound( y1 );
                y2 = qRound( y2 );
                x = qRound( x );
            }

            if ( polygon.size() == 0 )
                polygon += QPointF( v0, y1 );

            polygon += QPointF( x, y1 );
            polygon += QPointF( x, y2 );
        }
        previous = sample;
    }

    flushPolygon( painter, v0, polygon );
}

void QwtPlotHistogram::drawColumns( QPainter *painter,
    const QwtScaleMap &xMap, const QwtScaleMap &yMap,
    int from, int to ) const
{
    painter->setPen( d_data->pen );
    painter->setBrush( d_data->brush );

    const QwtSeriesData<QwtIntervalSample> *series = data();

    for ( int i = from; i <= to; i++ )
    {
        const QwtIntervalSample sample = series->sample( i );
        if ( !sample.interval.isNull() )
        {
            const QwtColumnRect rect = columnRect( sample, xMap, yMap );
            drawColumn( painter, rect, sample );
        }
    }
}

void QwtPlotHistogram::drawLines( QPainter *painter,
    const QwtScaleMap &xMap, const QwtScaleMap &yMap,
    int from, int to ) const
{
    const bool doAlign = QwtPainter::roundingAlignment( painter );

    painter->setPen( d_data->pen );
    painter->setBrush( Qt::NoBrush );

    const QwtSeriesData<QwtIntervalSample> *series = data();

    for ( int i = from; i <= to; i++ )
    {
        const QwtIntervalSample sample = series->sample( i );
        if ( !sample.interval.isNull() )
        {
            const QwtColumnRect rect = columnRect( sample, xMap, yMap );

            QRectF r = rect.toRect();
            if ( doAlign )
            {
                r.setLeft( qRound( r.left() ) );
                r.setRight( qRound( r.right() ) );
                r.setTop( qRound( r.top() ) );
                r.setBottom( qRound( r.bottom() ) );
            }

            switch ( rect.direction )
            {
                case QwtColumnRect::LeftToRight:
                {
                    QwtPainter::drawLine( painter,
                        r.topRight(), r.bottomRight() );
                    break;
                }
                case QwtColumnRect::RightToLeft:
                {
                    QwtPainter::drawLine( painter,
                        r.topLeft(), r.bottomLeft() );
                    break;
                }
                case QwtColumnRect::TopToBottom:
                {
                    QwtPainter::drawLine( painter,
                        r.bottomRight(), r.bottomLeft() );
                    break;
                }
                case QwtColumnRect::BottomToTop:
                {
                    QwtPainter::drawLine( painter,
                        r.topRight(), r.topLeft() );
                    break;
                }
            }
        }
    }
}

void QwtPlotHistogram::flushPolygon( QPainter *painter,
    double baseLine, QPolygonF &polygon ) const
{
    if ( polygon.size() == 0 )
        return;

    if ( orientation() == Qt::Horizontal )
        polygon += QPointF( baseLine, polygon.last().y() );
    else
        polygon += QPointF( polygon.last().x(), baseLine );

    if ( d_data->brush.style() != Qt::NoBrush )
    {
        painter->setPen( Qt::NoPen );
        painter->setBrush( d_data->brush );

        if ( orientation() == Qt::Horizontal )
        {
            polygon += QPointF( polygon.last().x(), baseLine );
            polygon += QPointF( polygon.first().x(), baseLine );
        }
        else
        {
            polygon += QPointF( baseLine, polygon.last().y() );
            polygon += QPointF( baseLine, polygon.first().y() );
        }

        QwtPainter::drawPolygon( painter, polygon );

        polygon.pop_back();
        polygon.pop_back();
    }
    if ( d_data->pen.style() != Qt::NoPen )
    {
        painter->setBrush( Qt::NoBrush );
        painter->setPen( d_data->pen );
        QwtPainter::drawPolyline( painter, polygon );
    }
    polygon.clear();
}

QwtColumnRect QwtPlotHistogram::columnRect( const QwtIntervalSample &sample,
    const QwtScaleMap &xMap, const QwtScaleMap &yMap ) const
{
    QwtColumnRect rect;

    const QwtInterval &iv = sample.interval;
    if ( !iv.isValid() )
        return rect;

    if ( orientation() == Qt::Horizontal )
    {
        const double x0 = xMap.transform( baseline() );
        const double x  = xMap.transform( sample.value );
        const double y1 = yMap.transform( iv.minValue() );
        const double y2 = yMap.transform( iv.maxValue() );

        rect.hInterval.setInterval( x0, x );
        rect.vInterval.setInterval( y1, y2, iv.borderFlags() );
        rect.direction = ( x < x0 ) ? QwtColumnRect::RightToLeft :
                         QwtColumnRect::LeftToRight;
    }
    else
    {
        const double x1 = xMap.transform( iv.minValue() );
        const double x2 = xMap.transform( iv.maxValue() );
        const double y0 = yMap.transform( baseline() );
        const double y = yMap.transform( sample.value );

        rect.hInterval.setInterval( x1, x2, iv.borderFlags() );
        rect.vInterval.setInterval( y0, y );
        rect.direction = ( y < y0 ) ? QwtColumnRect::BottomToTop :
            QwtColumnRect::TopToBottom;
    }

    return rect;
}

void QwtPlotHistogram::drawColumn( QPainter *painter,
    const QwtColumnRect &rect, const QwtIntervalSample &sample ) const
{
    Q_UNUSED( sample );

    if ( d_data->symbol &&
        ( d_data->symbol->style() != QwtColumnSymbol::NoStyle ) )
    {
        d_data->symbol->draw( painter, rect );
    }
    else
    {
        QRectF r = rect.toRect();
        if ( QwtPainter::roundingAlignment( painter ) )
        {
            r.setLeft( qRound( r.left() ) );
            r.setRight( qRound( r.right() ) );
            r.setTop( qRound( r.top() ) );
            r.setBottom( qRound( r.bottom() ) );
        }

        QwtPainter::drawRect( painter, r );
    }
}

QwtGraphic QwtPlotHistogram::legendIcon( int index, const QSizeF &size ) const
{
    Q_UNUSED( index );
    return defaultIcon( d_data->brush, size );
}