qwt_plot_shapeitem.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_shapeitem.h"
#include "qwt_scale_map.h"
#include "qwt_painter.h"
#include "qwt_weeding_curve_fitter.h"
#include "qwt_clipper.h"

static QPainterPath qwtTransformPath( const QwtScaleMap &xMap,
        const QwtScaleMap &yMap, const QPainterPath &path, bool doAlign )
{
    QPainterPath shape;
    shape.setFillRule( path.fillRule() );

    for ( int i = 0; i < path.elementCount(); i++ )
    {
        const QPainterPath::Element &element = path.elementAt( i );

        double x = xMap.transform( element.x );
        double y = yMap.transform( element.y );

        switch( element.type )
        {
            case QPainterPath::MoveToElement:
            {
                if ( doAlign )
                {
                    x = qRound( x );
                    y = qRound( y );
                }

                shape.moveTo( x, y );
                break;
            }
            case QPainterPath::LineToElement:
            {
                if ( doAlign )
                {
                    x = qRound( x );
                    y = qRound( y );
                }

                shape.lineTo( x, y );
                break;
            }
            case QPainterPath::CurveToElement:
            {
                const QPainterPath::Element& element1 = path.elementAt( ++i );
                const double x1 = xMap.transform( element1.x );
                const double y1 = yMap.transform( element1.y );

                const QPainterPath::Element& element2 = path.elementAt( ++i );
                const double x2 = xMap.transform( element2.x );
                const double y2 = yMap.transform( element2.y );

                shape.cubicTo( x, y, x1, y1, x2, y2 );
                break;
            }
            case QPainterPath::CurveToDataElement:
            {
                break;
            }
        }
    }

    return shape;
}


class QwtPlotShapeItem::PrivateData
{
public:
    PrivateData():
        legendMode( QwtPlotShapeItem::LegendColor ),
        renderTolerance( 0.0 )
    {
    }

    QwtPlotShapeItem::PaintAttributes paintAttributes;
    QwtPlotShapeItem::LegendMode legendMode;

    double renderTolerance;
    QRectF boundingRect;

    QPen pen;
    QBrush brush;
    QPainterPath shape;
};

QwtPlotShapeItem::QwtPlotShapeItem( const QString& title ):
    QwtPlotItem( QwtText( title ) )
{
    init();
}

QwtPlotShapeItem::QwtPlotShapeItem( const QwtText& title ):
    QwtPlotItem( title )
{
    init();
}

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

void QwtPlotShapeItem::init()
{
    d_data = new PrivateData();
    d_data->boundingRect = QwtPlotItem::boundingRect();

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

    setZ( 8.0 );
}

int QwtPlotShapeItem::rtti() const
{
    return QwtPlotItem::Rtti_PlotShape;
}

void QwtPlotShapeItem::setPaintAttribute( PaintAttribute attribute, bool on )
{
    if ( on )
        d_data->paintAttributes |= attribute;
    else
        d_data->paintAttributes &= ~attribute;
}

bool QwtPlotShapeItem::testPaintAttribute( PaintAttribute attribute ) const
{
    return ( d_data->paintAttributes & attribute );
}

void QwtPlotShapeItem::setLegendMode( LegendMode mode )
{
    if ( mode != d_data->legendMode )
    {
        d_data->legendMode = mode;
        legendChanged();
    }
}

QwtPlotShapeItem::LegendMode QwtPlotShapeItem::legendMode() const
{
    return d_data->legendMode;
}

QRectF QwtPlotShapeItem::boundingRect() const
{
    return d_data->boundingRect;
}

void QwtPlotShapeItem::setRect( const QRectF &rect ) 
{
    QPainterPath path;
    path.addRect( rect );

    setShape( path );
}

void QwtPlotShapeItem::setPolygon( const QPolygonF &polygon )
{
    QPainterPath shape;
    shape.addPolygon( polygon );

    setShape( shape );
}

void QwtPlotShapeItem::setShape( const QPainterPath &shape )
{
    if ( shape != d_data->shape )
    {
        d_data->shape = shape;
        if ( shape.isEmpty() )
        {
            d_data->boundingRect = QwtPlotItem::boundingRect();
        }
        else
        {
            d_data->boundingRect = shape.boundingRect();
        }

        itemChanged();
    }
}

QPainterPath QwtPlotShapeItem::shape() const
{
    return d_data->shape;
}

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

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

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

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

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

void QwtPlotShapeItem::setRenderTolerance( double tolerance )
{
    tolerance = qMax( tolerance, 0.0 );

    if ( tolerance != d_data->renderTolerance )
    {
        d_data->renderTolerance = tolerance;
        itemChanged();
    }
}

double QwtPlotShapeItem::renderTolerance() const
{
    return d_data->renderTolerance;
}

void QwtPlotShapeItem::draw( QPainter *painter,
    const QwtScaleMap &xMap, const QwtScaleMap &yMap,
    const QRectF &canvasRect ) const
{
    if ( d_data->shape.isEmpty() )
        return;

    if ( d_data->pen.style() == Qt::NoPen 
        && d_data->brush.style() == Qt::NoBrush )
    {
        return;
    }

    const QRectF cr = QwtScaleMap::invTransform(
        xMap, yMap, canvasRect.toRect() );

    const QRectF &br = d_data->boundingRect;

    if ( ( br.left() > cr.right() ) || ( br.right() < cr.left() )
        || ( br.top() > cr.bottom() ) || ( br.bottom() < cr.top() ) )
    {
        // outside the visisble area
        return;
    }

    const bool doAlign = QwtPainter::roundingAlignment( painter );

    QPainterPath path = qwtTransformPath( xMap, yMap, 
        d_data->shape, doAlign );

    if ( testPaintAttribute( QwtPlotShapeItem::ClipPolygons ) )
    {
        const qreal pw = qMax( qreal( 1.0 ), painter->pen().widthF());
        const QRectF clipRect = canvasRect.adjusted( -pw, -pw, pw, pw );

        QPainterPath clippedPath;
        clippedPath.setFillRule( path.fillRule() );

        QList<QPolygonF> polygons = path.toSubpathPolygons();
        for ( int i = 0; i < polygons.size(); i++ )
        {
            QwtClipper::clipPolygonF( clipRect, polygons[i], true );
            clippedPath.addPolygon( polygons[i] );

        }

        path = clippedPath;
    }

    if ( d_data->renderTolerance > 0.0 )
    {
        QwtWeedingCurveFitter fitter( d_data->renderTolerance );

        QPainterPath fittedPath;
        fittedPath.setFillRule( path.fillRule() );

        const QList<QPolygonF> polygons = path.toSubpathPolygons();
        for ( int i = 0; i < polygons.size(); i++ )
            fittedPath.addPolygon( fitter.fitCurve( polygons[ i ] ) );

        path = fittedPath;
    }

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

    painter->drawPath( path );
}

QwtGraphic QwtPlotShapeItem::legendIcon( int index,
    const QSizeF &size ) const
{
    Q_UNUSED( index );

    QwtGraphic icon;
    icon.setDefaultSize( size );

    if ( size.isEmpty() )
        return icon;

    if ( d_data->legendMode == QwtPlotShapeItem::LegendShape )
    {
        const QRectF &br = d_data->boundingRect;

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

        painter.translate( -br.topLeft() );

        painter.setPen( d_data->pen );
        painter.setBrush( d_data->brush );
        painter.drawPath( d_data->shape );
    }
    else
    {
        QColor iconColor;
        if ( d_data->brush.style() != Qt::NoBrush )
            iconColor = d_data->brush.color();
        else
            iconColor = d_data->pen.color();

        icon = defaultIcon( iconColor, size );
    }

    return icon;
}