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 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
            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() ) {
                    PaintingHelpers::paintPolyline( 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
        PaintingHelpers::paintPolyline( 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 );
}