qwt_plot_intervalcurve.cpp

/* -*- 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_intervalcurve.h"
#include "qwt_interval_symbol.h"
#include "qwt_scale_map.h"
#include "qwt_clipper.h"
#include "qwt_painter.h"
#include <string.h>

#include <qpainter.h>

static inline bool qwtIsHSampleInside( const QwtIntervalSample &sample,
    double xMin, double xMax, double yMin, double yMax )
{
    const double y = sample.value;
    const double x1 = sample.interval.minValue();
    const double x2 = sample.interval.maxValue();

    const bool isOffScreen = ( y < yMin ) || ( y > yMax )
        || ( x1 < xMin && x2 < xMin ) || ( x1 > xMax && x2 > xMax );

    return !isOffScreen;
}

static inline bool qwtIsVSampleInside( const QwtIntervalSample &sample,
    double xMin, double xMax, double yMin, double yMax )
{
    const double x = sample.value;
    const double y1 = sample.interval.minValue();
    const double y2 = sample.interval.maxValue();

    const bool isOffScreen = ( x < xMin ) || ( x > xMax )
        || ( y1 < yMin && y2 < yMin ) || ( y1 > yMax && y2 > yMax );

    return !isOffScreen;
}

class QwtPlotIntervalCurve::PrivateData
{
public:
    PrivateData():
        style( QwtPlotIntervalCurve::Tube ),
        symbol( NULL ),
        pen( Qt::black ),
        brush( Qt::white )
    {
        paintAttributes = QwtPlotIntervalCurve::ClipPolygons;
        paintAttributes |= QwtPlotIntervalCurve::ClipSymbol;

        pen.setCapStyle( Qt::FlatCap );
    }

    ~PrivateData()
    {
        delete symbol;
    }

    QwtPlotIntervalCurve::CurveStyle style;
    const QwtIntervalSymbol *symbol;

    QPen pen;
    QBrush brush;

    QwtPlotIntervalCurve::PaintAttributes paintAttributes;
};

/*!
  Constructor
  \param title Title of the curve
*/
QwtPlotIntervalCurve::QwtPlotIntervalCurve( const QwtText &title ):
    QwtPlotSeriesItem( title )
{
    init();
}

/*!
  Constructor
  \param title Title of the curve
*/
QwtPlotIntervalCurve::QwtPlotIntervalCurve( const QString &title ):
    QwtPlotSeriesItem( QwtText( title ) )
{
    init();
}

//! Destructor
QwtPlotIntervalCurve::~QwtPlotIntervalCurve()
{
    delete d_data;
}

//! Initialize internal members
void QwtPlotIntervalCurve::init()
{
    setItemAttribute( QwtPlotItem::Legend, true );
    setItemAttribute( QwtPlotItem::AutoScale, true );

    d_data = new PrivateData;
    setData( new QwtIntervalSeriesData() );

    setZ( 19.0 );
}

//! \return QwtPlotItem::Rtti_PlotIntervalCurve
int QwtPlotIntervalCurve::rtti() const
{
    return QwtPlotIntervalCurve::Rtti_PlotIntervalCurve;
}

/*!
  Specify an attribute how to draw the curve

  \param attribute Paint attribute
  \param on On/Off
  \sa testPaintAttribute()
*/
void QwtPlotIntervalCurve::setPaintAttribute(
    PaintAttribute attribute, bool on )
{
    if ( on )
        d_data->paintAttributes |= attribute;
    else
        d_data->paintAttributes &= ~attribute;
}

/*!
    \return True, when attribute is enabled
    \sa PaintAttribute, setPaintAttribute()
*/
bool QwtPlotIntervalCurve::testPaintAttribute(
    PaintAttribute attribute ) const
{
    return ( d_data->paintAttributes & attribute );
}

/*!
  Initialize data with an array of samples.
  \param samples Vector of samples
*/
void QwtPlotIntervalCurve::setSamples(
    const QVector<QwtIntervalSample> &samples )
{
    setData( new QwtIntervalSeriesData( samples ) );
}

/*!
  Assign a series of samples
    
  setSamples() is just a wrapper for setData() without any additional
  value - beside that it is easier to find for the developer.
    
  \param data Data
  \warning The item takes ownership of the data object, deleting
           it when its not used anymore.
*/
void QwtPlotIntervalCurve::setSamples( 
    QwtSeriesData<QwtIntervalSample> *data )
{
    setData( data );
}

/*!
  Set the curve's drawing style

  \param style Curve style
  \sa CurveStyle, style()
*/
void QwtPlotIntervalCurve::setStyle( CurveStyle style )
{
    if ( style != d_data->style )
    {
        d_data->style = style;

        legendChanged();
        itemChanged();
    }
}

/*!
    \return Style of the curve
    \sa setStyle()
*/
QwtPlotIntervalCurve::CurveStyle QwtPlotIntervalCurve::style() const
{
    return d_data->style;
}

/*!
  Assign a symbol.

  \param symbol Symbol
  \sa symbol()
*/
void QwtPlotIntervalCurve::setSymbol( const QwtIntervalSymbol *symbol )
{
    if ( symbol != d_data->symbol )
    {
        delete d_data->symbol;
        d_data->symbol = symbol;

        legendChanged();
        itemChanged();
    }
}

/*!
  \return Current symbol or NULL, when no symbol has been assigned
  \sa setSymbol()
*/
const QwtIntervalSymbol *QwtPlotIntervalCurve::symbol() const
{
    return d_data->symbol;
}

/*!
  Build and assign a pen
    
  In Qt5 the default pen width is 1.0 ( 0.0 in Qt4 ) what makes it
  non cosmetic ( see QPen::isCosmetic() ). This method has been introduced
  to hide this incompatibility.
    
  \param color Pen color
  \param width Pen width
  \param style Pen style
    
  \sa pen(), brush()
 */
void QwtPlotIntervalCurve::setPen( const QColor &color, qreal width, Qt::PenStyle style )
{   
    setPen( QPen( color, width, style ) );
}   

/*!
  \brief Assign a pen
  \param pen New pen
  \sa pen(), brush()
*/
void QwtPlotIntervalCurve::setPen( const QPen &pen )
{
    if ( pen != d_data->pen )
    {
        d_data->pen = pen;

        legendChanged();
        itemChanged();
    }
}

/*!
    \return Pen used to draw the lines
    \sa setPen(), brush()
*/
const QPen& QwtPlotIntervalCurve::pen() const
{
    return d_data->pen;
}

/*!
  Assign a brush.

  The brush is used to fill the area in Tube style().

  \param brush Brush
  \sa brush(), pen(), setStyle(), CurveStyle
*/
void QwtPlotIntervalCurve::setBrush( const QBrush &brush )
{
    if ( brush != d_data->brush )
    {
        d_data->brush = brush;

        legendChanged();
        itemChanged();
    }
}

/*!
  \return Brush used to fill the area in Tube style()
  \sa setBrush(), setStyle(), CurveStyle
*/
const QBrush& QwtPlotIntervalCurve::brush() const
{
    return d_data->brush;
}

/*!
  \return Bounding rectangle of all samples.
  For an empty series the rectangle is invalid.
*/
QRectF QwtPlotIntervalCurve::boundingRect() const
{
    QRectF rect = QwtPlotSeriesItem::boundingRect();
    if ( rect.isValid() && orientation() == Qt::Vertical )
        rect.setRect( rect.y(), rect.x(), rect.height(), rect.width() );

    return rect;
}

/*!
  Draw a subset of the samples

  \param painter Painter
  \param xMap Maps x-values into pixel coordinates.
  \param yMap Maps y-values into pixel coordinates.
  \param canvasRect Contents rectangle of the canvas
  \param from Index of the first sample to be painted
  \param to Index of the last sample to be painted. If to < 0 the
         series will be painted to its last sample.

  \sa drawTube(), drawSymbols()
*/
void QwtPlotIntervalCurve::drawSeries( QPainter *painter,
    const QwtScaleMap &xMap, const QwtScaleMap &yMap,
    const QRectF &canvasRect, int from, int to ) const
{
    if ( to < 0 )
        to = dataSize() - 1;

    if ( from < 0 )
        from = 0;

    if ( from > to )
        return;

    switch ( d_data->style )
    {
        case Tube:
            drawTube( painter, xMap, yMap, canvasRect, from, to );
            break;

        case NoCurve:
        default:
            break;
    }

    if ( d_data->symbol &&
        ( d_data->symbol->style() != QwtIntervalSymbol::NoSymbol ) )
    {
        drawSymbols( painter, *d_data->symbol,
            xMap, yMap, canvasRect, from, to );
    }
}

/*!
  Draw a tube

  Builds 2 curves from the upper and lower limits of the intervals
  and draws them with the pen(). The area between the curves is
  filled with the brush().

  \param painter Painter
  \param xMap Maps x-values into pixel coordinates.
  \param yMap Maps y-values into pixel coordinates.
  \param canvasRect Contents rectangle of the canvas
  \param from Index of the first sample to be painted
  \param to Index of the last sample to be painted. If to < 0 the
         series will be painted to its last sample.

  \sa drawSeries(), drawSymbols()
*/
void QwtPlotIntervalCurve::drawTube( QPainter *painter,
    const QwtScaleMap &xMap, const QwtScaleMap &yMap,
    const QRectF &canvasRect, int from, int to ) const
{
    const bool doAlign = QwtPainter::roundingAlignment( painter );

    painter->save();

    const size_t size = to - from + 1;
    QPolygonF polygon( 2 * size );
    QPointF *points = polygon.data();

    for ( uint i = 0; i < size; i++ )
    {
        QPointF &minValue = points[i];
        QPointF &maxValue = points[2 * size - 1 - i];

        const QwtIntervalSample intervalSample = sample( from + i );
        if ( orientation() == Qt::Vertical )
        {
            double x = xMap.transform( intervalSample.value );
            double y1 = yMap.transform( intervalSample.interval.minValue() );
            double y2 = yMap.transform( intervalSample.interval.maxValue() );
            if ( doAlign )
            {
                x = qRound( x );
                y1 = qRound( y1 );
                y2 = qRound( y2 );
            }

            minValue.rx() = x;
            minValue.ry() = y1;
            maxValue.rx() = x;
            maxValue.ry() = y2;
        }
        else
        {
            double y = yMap.transform( intervalSample.value );
            double x1 = xMap.transform( intervalSample.interval.minValue() );
            double x2 = xMap.transform( intervalSample.interval.maxValue() );
            if ( doAlign )
            {
                y = qRound( y );
                x1 = qRound( x1 );
                x2 = qRound( x2 );
            }

            minValue.rx() = x1;
            minValue.ry() = y;
            maxValue.rx() = x2;
            maxValue.ry() = y;
        }
    }

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

        if ( d_data->paintAttributes & ClipPolygons )
        {
            const qreal m = 1.0;
            const QPolygonF p = QwtClipper::clipPolygonF(
               canvasRect.adjusted( -m, -m, m, m ), polygon, true );

            QwtPainter::drawPolygon( painter, p );
        }
        else
        {
            QwtPainter::drawPolygon( painter, polygon );
        }
    }

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

        if ( d_data->paintAttributes & ClipPolygons )
        {
            qreal pw = qMax( qreal( 1.0 ), painter->pen().widthF() );
            const QRectF clipRect = canvasRect.adjusted( -pw, -pw, pw, pw );

            QPolygonF p;

            p.resize( size );
            ::memcpy( p.data(), points, size * sizeof( QPointF ) );
            p = QwtClipper::clipPolygonF( clipRect, p );
            QwtPainter::drawPolyline( painter, p );

            p.resize( size );
            ::memcpy( p.data(), points + size, size * sizeof( QPointF ) );
            p = QwtClipper::clipPolygonF( clipRect, p );
            QwtPainter::drawPolyline( painter, p );
        }
        else
        {
            QwtPainter::drawPolyline( painter, points, size );
            QwtPainter::drawPolyline( painter, points + size, size );
        }
    }

    painter->restore();
}

/*!
  Draw symbols for a subset of the samples

  \param painter Painter
  \param symbol Interval symbol
  \param xMap x map
  \param yMap y map
  \param canvasRect Contents rectangle of the canvas
  \param from Index of the first sample to be painted
  \param to Index of the last sample to be painted

  \sa setSymbol(), drawSeries(), drawTube()
*/
void QwtPlotIntervalCurve::drawSymbols(
    QPainter *painter, const QwtIntervalSymbol &symbol,
    const QwtScaleMap &xMap, const QwtScaleMap &yMap,
    const QRectF &canvasRect, int from, int to ) const
{
    painter->save();

    QPen pen = symbol.pen();
    pen.setCapStyle( Qt::FlatCap );

    painter->setPen( pen );
    painter->setBrush( symbol.brush() );

    const QRectF tr = QwtScaleMap::invTransform( xMap, yMap, canvasRect );

    const double xMin = tr.left();
    const double xMax = tr.right();
    const double yMin = tr.top();
    const double yMax = tr.bottom();

    const bool doClip = d_data->paintAttributes & ClipSymbol;

    for ( int i = from; i <= to; i++ )
    {
        const QwtIntervalSample s = sample( i );

        if ( orientation() == Qt::Vertical )
        {
            if ( !doClip || qwtIsVSampleInside( s, xMin, xMax, yMin, yMax ) )
            {
                const double x = xMap.transform( s.value );
                const double y1 = yMap.transform( s.interval.minValue() );
                const double y2 = yMap.transform( s.interval.maxValue() );

                symbol.draw( painter, orientation(),
                    QPointF( x, y1 ), QPointF( x, y2 ) );
            }
        }
        else
        {
            if ( !doClip || qwtIsHSampleInside( s, xMin, xMax, yMin, yMax ) )
            {
                const double y = yMap.transform( s.value );
                const double x1 = xMap.transform( s.interval.minValue() );
                const double x2 = xMap.transform( s.interval.maxValue() );

                symbol.draw( painter, orientation(),
                    QPointF( x1, y ), QPointF( x2, y ) );
            }
        }
    }

    painter->restore();
}

/*!
  \return Icon for the legend

  In case of Tube style() the icon is a plain rectangle filled with the brush().
  If a symbol is assigned it is scaled to size.

  \param index Index of the legend entry 
               ( ignored as there is only one )
  \param size Icon size
    
  \sa QwtPlotItem::setLegendIconSize(), QwtPlotItem::legendData()
*/
QwtGraphic QwtPlotIntervalCurve::legendIcon( 
    int index, const QSizeF &size ) const
{
    Q_UNUSED( index );

    if ( size.isEmpty() )
        return QwtGraphic();

    QwtGraphic icon;
    icon.setDefaultSize( size );
    icon.setRenderHint( QwtGraphic::RenderPensUnscaled, true );

    QPainter painter( &icon );
    painter.setRenderHint( QPainter::Antialiasing,
        testRenderHint( QwtPlotItem::RenderAntialiased ) );

    if ( d_data->style == Tube )
    {
        QRectF r( 0, 0, size.width(), size.height() );
        painter.fillRect( r, d_data->brush );
    }

    if ( d_data->symbol &&
        ( d_data->symbol->style() != QwtIntervalSymbol::NoSymbol ) )
    {
        QPen pen = d_data->symbol->pen();
        pen.setWidthF( pen.widthF() );
        pen.setCapStyle( Qt::FlatCap );

        painter.setPen( pen );
        painter.setBrush( d_data->symbol->brush() );

        if ( orientation() == Qt::Vertical )
        {
            const double x = 0.5 * size.width();

            d_data->symbol->draw( &painter, orientation(),
                QPointF( x, 0 ), QPointF( x, size.height() - 1.0 ) );
        }
        else
        {
            const double y = 0.5 * size.height();

            d_data->symbol->draw( &painter, orientation(),
                QPointF( 0.0, y ), QPointF( size.width() - 1.0, y ) );
        }
    }

    return icon;
}