PaintingHelpers_p.cpp

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** Copyright (C) 2001-2020 Klaralvdalens Datakonsult AB.  All rights reserved.
**
** This file is part of the KD Chart library.
**
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** accordance with the KD Chart Commercial License Agreement provided with
** the Software.
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** This file may be distributed and/or modified under the terms of the
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** Free Software Foundation and appearing in the file LICENSE.GPL.txt included.
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#include "PaintingHelpers_p.h"

#include "KDChartGlobal.h"

#include "KDChartAbstractDiagram.h"
#include "KDChartAbstractDiagram_p.h"
#include "KDChartCartesianCoordinatePlane.h"
#include "KDChartLineDiagram.h"
#include "KDChartLineDiagram_p.h"
#include "KDChartValueTrackerAttributes.h"
#include "KDChartPaintContext.h"
#include "KDChartPainterSaver_p.h"
#include "KDChartPlotter.h"
#include "KDChartPrintingParameters.h"
#include "KDChartThreeDLineAttributes.h"
#include "ReverseMapper.h"

namespace KDChart {
namespace PaintingHelpers {

const QPointF project( const QPointF& point, const ThreeDLineAttributes& tdAttributes )
{
    //Pending Michel FIXME - the rotation does not work as expected atm
    qreal xrad = DEGTORAD( tdAttributes.lineXRotation() );
    qreal yrad = DEGTORAD( tdAttributes.lineYRotation() );
    return QPointF( point.x() * cos( yrad ) + tdAttributes.depth() * sin( yrad ),
                    point.y() * cos( xrad ) - tdAttributes.depth() * sin( xrad ) );
}

QPainterPath fitPoints( const QPolygonF &points, qreal tension )
{
    QPainterPath path;
    path.moveTo( points.at( 0 ) );
    const int count = points.size();

    // TODO: convert to lambda when we stop caring about pre-C++11
    // auto dataAt = [&] (int i) {
    //     return i < 0 || i >= count ? QPointF(NAN, NAN) : points.at( i );
    // };
    struct dataAtLambda {
        dataAtLambda(const QPolygonF &points, int count)
            : points(points)
            , count(count)
        {}

        const QPolygonF &points;
        int count;

        QPointF operator() (int i) const
        {
            return i < 0 || i >= count ? QPointF(NAN, NAN) : points.at( i );
        }
    };

    dataAtLambda dataAt(points, count);

    for (int i = 1; i < count; ++i) {
        addSplineChunkTo( path, tension, dataAt( i - 2 ), points.at( i - 1 ), points.at( i ), dataAt( i + 1 ) );
    }

    return path;
}

void paintPolyline( PaintContext* ctx, const QBrush& brush, const QPen& pen, const QPolygonF& points )
{
    ctx->painter()->setBrush( brush );
    ctx->painter()->setPen( PrintingParameters::scalePen(
        QPen( pen.color(), pen.width(), pen.style(), Qt::FlatCap, Qt::MiterJoin ) ) );
#if QT_VERSION > 0x040299
    ctx->painter()->drawPolyline( points );
#else
    // FIXME (Mirko) verify, this sounds reverse-logical
    // For Qt versions older than 4.3 drawPolyline is VERY slow
    // so we use traditional line segments drawing instead then.
    for ( int i = 0; i < points.size()-1; ++i ) {
        ctx->painter()->drawLine( points.at( i ), points.at( i + 1 ) );
    }
#endif
}

void paintSpline( PaintContext* ctx, const QBrush& brush, const QPen& pen, const QPolygonF& points, qreal tension )
{
    if (points.size() < 3) {
        paintPolyline( ctx, brush, pen, points );
        return;
    }

    ctx->painter()->setBrush( brush );
    ctx->painter()->setBrush( QBrush() );
    ctx->painter()->setPen( PrintingParameters::scalePen(
        QPen( pen.color(), pen.width(), pen.style(), Qt::FlatCap, Qt::MiterJoin ) ) );

    ctx->painter()->drawPath( fitPoints(points, tension) );
}

void paintThreeDLines( PaintContext* ctx, AbstractDiagram *diagram, const QModelIndex& index,
                       const QPointF& from, const QPointF& to, const ThreeDLineAttributes& tdAttributes,
                       ReverseMapper* reverseMapper )
{
    const QPointF topLeft = project( from, tdAttributes );
    const QPointF topRight = project ( to, tdAttributes );
    const QPolygonF segment = QPolygonF() << from << topLeft << topRight << to;

    QBrush indexBrush( diagram->brush( index ) );
    indexBrush = tdAttributes.threeDBrush( indexBrush, QRectF(topLeft, topRight) );

    const PainterSaver painterSaver( ctx->painter() );

    ctx->painter()->setRenderHint( QPainter::Antialiasing, diagram->antiAliasing() );
    ctx->painter()->setBrush( indexBrush );
    ctx->painter()->setPen( PrintingParameters::scalePen( diagram->pen( index ) ) );

    reverseMapper->addPolygon( index.row(), index.column(), segment );
    ctx->painter()->drawPolygon( segment );
}

void paintValueTracker( PaintContext* ctx, const ValueTrackerAttributes& vt, const QPointF& at )
{
    CartesianCoordinatePlane* plane = qobject_cast<CartesianCoordinatePlane*>( ctx->coordinatePlane() );
    if ( !plane )
        return;

    DataDimensionsList gridDimensions = ctx->coordinatePlane()->gridDimensionsList();
    const QPointF bottomLeft( ctx->coordinatePlane()->translate(
                              QPointF( plane->isHorizontalRangeReversed() ?
                                           gridDimensions.at( 0 ).end :
                                           gridDimensions.at( 0 ).start,
                                       plane->isVerticalRangeReversed() ?
                                           gridDimensions.at( 1 ).end :
                                           gridDimensions.at( 1 ).start ) ) );
    const QPointF topRight( ctx->coordinatePlane()->translate(
                            QPointF( plane->isHorizontalRangeReversed() ?
                                         gridDimensions.at( 0 ).start :
                                         gridDimensions.at( 0 ).end,
                                     plane->isVerticalRangeReversed() ?
                                         gridDimensions.at( 1 ).start :
                                         gridDimensions.at( 1 ).end ) ) );
    const QPointF markerPoint = at;

    QPointF startPoint;
    if ( vt.orientations() & Qt::Horizontal ) {
        startPoint = QPointF( bottomLeft.x(), at.y() );
    } else {
        startPoint = QPointF( at.x(), topRight.y() );
    }

    QPointF endPoint;
    if ( vt.orientations() & Qt::Vertical ) {
        endPoint = QPointF( at.x(), bottomLeft.y() );
    } else {
        endPoint = QPointF( topRight.x(), at.y() );
    }

    const QSizeF markerSize = vt.markerSize();
    const QRectF ellipseMarker = QRectF( at.x() - markerSize.width() / 2,
                                         at.y() - markerSize.height() / 2,
                                         markerSize.width(), markerSize.height() );

    QPointF startMarker[3];
    if ( vt.orientations() & Qt::Horizontal ) {
        startMarker[0] = startPoint + QPointF( 0,  markerSize.height() / 2 );
        startMarker[1] = startPoint + QPointF( markerSize.width() / 2, 0 );
        startMarker[2] = startPoint - QPointF( 0, markerSize.height() / 2 );
    } else {
        startMarker[0] = startPoint + QPointF( 0, markerSize.height() / 2 );
        startMarker[1] = startPoint + QPointF( markerSize.width() / 2, 0 );
        startMarker[2] = startPoint - QPointF( markerSize.width() / 2, 0 );
    }

    QPointF endMarker[3];

    if ( vt.orientations() & Qt::Vertical ) {
        endMarker[0] = endPoint + QPointF( markerSize.width() / 2, 0 );
        endMarker[1] = endPoint - QPointF( 0, markerSize.height() / 2 );
        endMarker[2] = endPoint - QPointF( markerSize.width() / 2, 0 );
    } else {
        endMarker[0] = endPoint + QPointF( 0,  markerSize.width() / 2 );
        endMarker[1] = endPoint - QPointF( 0, markerSize.height() / 2 );
        endMarker[2] = endPoint - QPointF( markerSize.width() / 2, 0 );
    }

    QPointF topLeft = startPoint;
    QPointF bottomRightOffset = endPoint - topLeft;
    QSizeF size( bottomRightOffset.x(), bottomRightOffset.y() );
    QRectF area( topLeft, size );

    PainterSaver painterSaver( ctx->painter() );
    ctx->painter()->setPen( PrintingParameters::scalePen( vt.linePen() ) );
    ctx->painter()->setBrush( QBrush() );
    ctx->painter()->drawLine( markerPoint, startPoint );
    ctx->painter()->drawLine( markerPoint, endPoint );

    ctx->painter()->fillRect( area, vt.areaBrush() );

    ctx->painter()->setPen( PrintingParameters::scalePen( vt.markerPen() ) );
    ctx->painter()->setBrush( vt.markerBrush() );
    ctx->painter()->drawEllipse( ellipseMarker );

    ctx->painter()->setPen( PrintingParameters::scalePen( vt.arrowBrush().color() ) );
    ctx->painter()->setBrush( vt.arrowBrush() );
    ctx->painter()->drawPolygon( startMarker, 3 );
    ctx->painter()->drawPolygon( endMarker, 3 );
}

// ### for BC reasons we cannot insert a common interface for LineDiagram and Plotter into the class
//     hierarchy, so we have to use hacks to use their common methods
static ThreeDLineAttributes threeDLineAttributes( AbstractDiagram* diagram, const QModelIndex& index )
{
    if ( Plotter *plotter = qobject_cast< Plotter* >( diagram ) ) {
        return plotter->threeDLineAttributes( index );
    } else if ( LineDiagram *lineDiagram = qobject_cast< LineDiagram* >( diagram ) ) {
        return lineDiagram->threeDLineAttributes( index );
    }
    Q_ASSERT( false );
    return ThreeDLineAttributes();
}

static ValueTrackerAttributes valueTrackerAttributes( AbstractDiagram* diagram, const QModelIndex& index )
{
    if ( Plotter *plotter = qobject_cast< Plotter* >( diagram ) ) {
        return plotter->valueTrackerAttributes( index );
    } else if ( LineDiagram *lineDiagram = qobject_cast< LineDiagram* >( diagram ) ) {
        return lineDiagram->valueTrackerAttributes( index );
    }
    Q_ASSERT( false );
    return ValueTrackerAttributes();
}

void paintObject ( AbstractDiagram::Private *diagramPrivate, PaintContext* ctx, const QBrush& brush, const QPen& pen, const QPolygonF& points )
{
    qreal tension = 0;

    if ( LineDiagram::Private* lineDiagram = dynamic_cast<LineDiagram::Private*>( diagramPrivate ) ) {
        tension = lineDiagram->tension;
    }

    if ( qFuzzyIsNull(tension) ) {
        paintPolyline( ctx, brush, pen, points );
    } else {
        paintSpline( ctx, brush, pen, points, tension );
    }
}

void paintElements( AbstractDiagram::Private *diagramPrivate, PaintContext* ctx,
                    const LabelPaintCache& lpc, const LineAttributesInfoList& lineList )
{
    AbstractDiagram* diagram = diagramPrivate->diagram;
    // paint all lines and their attributes
    const PainterSaver painterSaver( ctx->painter() );
    ctx->painter()->setRenderHint( QPainter::Antialiasing, diagram->antiAliasing() );

    QBrush curBrush;
    QPen curPen;
    QPolygonF points;
    KDAB_FOREACH ( const LineAttributesInfo& lineInfo, lineList ) {
        const QModelIndex& index = lineInfo.index;
        const ThreeDLineAttributes td = threeDLineAttributes( diagram, index );

        if ( td.isEnabled() ) {
            PaintingHelpers::paintThreeDLines( ctx, diagram, index, lineInfo.value,
                                               lineInfo.nextValue, td, &diagramPrivate->reverseMapper );
        } else {
            const QBrush brush( diagram->brush( index ) );
            const QPen pen( diagram->pen( index ) );

            // line goes from lineInfo.value to lineInfo.nextValue
            // We don't want it added if we're not drawing it, since the reverse mapper is used
            // for lookup when trying to find e.g. tooltips. Having the line added when invisible gives
            // us tooltips in empty areas.
            if (pen.style() != Qt::NoPen)
                diagramPrivate->reverseMapper.addLine( lineInfo.index.row(), lineInfo.index.column(),
                                                       lineInfo.value, lineInfo.nextValue );

            if ( points.count() && points.last() == lineInfo.value && curBrush == brush && curPen == pen ) {
                // continue the current run of lines
            } else {
                // different painter settings or discontinuous line: start a new run of lines
                if ( points.count() ) {
                    paintObject( diagramPrivate, ctx, curBrush, curPen, points );
                }
                curBrush = brush;
                curPen = pen;
                points.clear();
                points << lineInfo.value;
            }
            points << lineInfo.nextValue;
        }
    }
    if ( points.count() ) {
        // the last run of lines is yet to be painted - do it now
        paintObject( diagramPrivate, ctx, curBrush, curPen, points );
    }

    KDAB_FOREACH ( const LineAttributesInfo& lineInfo, lineList ) {
        const ValueTrackerAttributes vt = valueTrackerAttributes( diagram, lineInfo.index );
        if ( vt.isEnabled() ) {
            PaintingHelpers::paintValueTracker( ctx, vt, lineInfo.nextValue );
        }
    }

    // paint all data value texts and the point markers
    diagramPrivate->paintDataValueTextsAndMarkers( ctx, lpc, true );
}

void paintAreas( AbstractDiagram::Private* diagramPrivate, PaintContext* ctx, const QModelIndex& index,
                 const QList< QPolygonF >& areas, uint opacity )
{
    AbstractDiagram* diagram = diagramPrivate->diagram;
    QPainterPath path;
    for ( int i = 0; i < areas.count(); ++i )
    {
        const QPolygonF& p = areas[ i ];
        path.addPolygon( p );
        diagramPrivate->reverseMapper.addPolygon( index.row(), index.column(), p );
        path.closeSubpath();
    }

    ThreeDLineAttributes threeDAttrs = threeDLineAttributes( diagram, index );
    QBrush trans = diagram->brush( index );
    if ( threeDAttrs.isEnabled() ) {
        trans = threeDAttrs.threeDBrush( trans, path.boundingRect() );
    }
    QColor transColor = trans.color();
    transColor.setAlpha( opacity );
    trans.setColor(transColor);
    QPen indexPen = diagram->pen(index);
    indexPen.setBrush( trans );
    const PainterSaver painterSaver( ctx->painter() );

    ctx->painter()->setRenderHint( QPainter::Antialiasing, diagram->antiAliasing() );
    ctx->painter()->setPen( PrintingParameters::scalePen( indexPen ) );
    ctx->painter()->setBrush( trans );

    ctx->painter()->drawPath( path );
}

void paintAreas( AbstractDiagram::Private* diagramPrivate, PaintContext* ctx, const QModelIndex& index,
                 const QList< QPainterPath >& areas, uint opacity )
{
    AbstractDiagram* diagram = diagramPrivate->diagram;
    QPainterPath path;
    for ( int i = 0; i < areas.count(); ++i )
    {
        path += areas[ i ];
        // diagramPrivate->reverseMapper.addPolygon( index.row(), index.column(), p );
    }

    QBrush trans = diagram->brush( index );
    QColor transColor = trans.color();
    transColor.setAlpha( opacity );
    trans.setColor( transColor );
    QPen indexPen = diagram->pen( index );
    indexPen.setBrush( trans );
    const PainterSaver painterSaver( ctx->painter() );

    ctx->painter()->setRenderHint( QPainter::Antialiasing, diagram->antiAliasing() );
    ctx->painter()->setPen( PrintingParameters::scalePen( indexPen ) );
    ctx->painter()->setBrush( trans );

    ctx->painter()->drawPath( path );
}

} // namespace PaintingHelpers
} // namespace KDChart