inline void QwtPolygonClipperF::addPoint(QwtPolygonF &pa, uint pos, const QwtDoublePoint &point) const
{
    if ( uint(pa.size()) <= pos ) 
        pa.resize(pos + 5);

    pa[(int)pos] = point;
}
void QwtPolygonClipperF::clipEdge(Edge edge, 
    const QwtPolygonF &pa, QwtPolygonF &cpa) const
{
    if ( pa.count() == 0 )
    {
        cpa.resize(0);
        return;
    }

    unsigned int count = 0;

    QwtDoublePoint p1 = pa[0];
    if ( insideEdge(p1, edge) )
        addPoint(cpa, count++, p1);

    const uint nPoints = pa.size();
    for ( uint i = 1; i < nPoints; i++ )
    {
        const QwtDoublePoint p2 = pa[(int)i];
        if ( insideEdge(p2, edge) )
        {
            if ( insideEdge(p1, edge) )
                addPoint(cpa, count++, p2);
            else
            {
                addPoint(cpa, count++, intersectEdge(p1, p2, edge));
                addPoint(cpa, count++, p2);
            }
        }
        else
        {
            if ( insideEdge(p1, edge) )
                addPoint(cpa, count++, intersectEdge(p1, p2, edge));
        }
        p1 = p2;
    }
    cpa.resize(count);
}
/*!
  \brief Complete a polygon to be a closed polygon
         including the area between the original polygon
         and the baseline.
  \param xMap X map
  \param yMap Y map
  \param pa Polygon to be completed
*/
void QwtPlotCurve::closePolyline(
    const QwtScaleMap &xMap, const QwtScaleMap &yMap,
    QwtPolygonF &pa) const
{
    const int sz = pa.size();
    if ( sz < 2 )
        return;

    pa.resize(sz + 2);

    if ( d_data->curveType == QwtPlotCurve::Xfy )
    {
        pa[sz] = QPointF(xMap.transform(d_data->reference), pa[sz - 1].y());
        pa[sz + 1] = QPointF(xMap.transform(d_data->reference), pa[0].y());
    }
    else
    {
        pa[sz] = QPointF(pa[sz - 1].x(), yMap.transform(d_data->reference));
        pa[pa.size() - 1] = QPointF(pa[0].x(), yMap.transform(d_data->reference));
    }
}
/*!
  Draw dots

  \param painter Painter
  \param xMap x map
  \param yMap y map
  \param from index of the first point to be painted
  \param to index of the last point to be painted

  \sa draw(), drawCurve(), drawSticks(), drawLines(), drawSteps()
*/
void QwtPlotCurve::drawDots(QPainter *painter,
    const QwtScaleMap &xMap, const QwtScaleMap &yMap,
    int from, int to) const
{
    const QRect window = painter->window();
    if ( window.isEmpty() )
        return;

    const bool doFill = d_data->brush.style() != Qt::NoBrush;

    QwtPolygonF polyline;
    if ( doFill )
        polyline.resize(to - from + 1);

    if ( to > from && d_data->paintAttributes & PaintFiltered )
    {
        if ( doFill )
        {
            QPointF pp( xMap.xTransform(x(from)), yMap.xTransform(y(from)) );

            QwtPainter::drawPoint(painter, pp.x(), pp.y());
            polyline[0] = pp;

            int count = 1;
            for (int i = from + 1; i <= to; i++)
            {
                const QPointF pi(xMap.xTransform(x(i)), yMap.xTransform(y(i)));
                if ( pi != pp )
                {
                    QwtPainter::drawPoint(painter, pi.x(), pi.y());

                    polyline[count] = pi;
                    count++;

                    pp = pi;
                }
            }
            if ( int(polyline.size()) != count )
                polyline.resize(count);
        }
        else
        {
            // if we don't need to fill, we can sort out
            // duplicates independent from the order

            PrivateData::PixelMatrix pixelMatrix(window);

            for (int i = from; i <= to; i++)
            {
                const QPointF p( xMap.xTransform(x(i)), yMap.xTransform(y(i)) );

                if ( pixelMatrix.testPixel(p.toPoint()) )
                    QwtPainter::drawPoint(painter, p.x(), p.y());
            }
        }
    }
    else
    {
        for (int i = from; i <= to; i++)
        {
            const double xi = xMap.xTransform(x(i));
            const double yi = yMap.xTransform(y(i));
            QwtPainter::drawPoint(painter, xi, yi);

            if ( doFill )
                polyline[i - from] = QPointF(xi, yi);
        }
    }

    if ( doFill )
    {
        if ( d_data->paintAttributes & ClipPolygons )
            polyline = QwtClipper::clipPolygonF(painter->window(), polyline);

        fillCurve(painter, xMap, yMap, polyline);
    }
}
// modified by Ion Vasilief in order to use floating point coordinates
void QwtPlotCurve::drawLines(QPainter *painter,
    const QwtScaleMap &xMap, const QwtScaleMap &yMap,
    int from, int to) const
{
    int size = to - from + 1;
    if ( size <= 0 )
        return;

    QwtPolygonF polyline;
    if ( ( d_data->attributes & Fitted ) && d_data->curveFitter )
    {
        // Transform x and y values to window coordinates
        // to avoid a distinction between linear and
        // logarithmic scales.

        QPolygonF points(size);
        for (int i = from; i <= to; i++)
        {
            QwtDoublePoint &p = points[i];
            p.setX( xMap.xTransform(x(i)) );
            p.setY( yMap.xTransform(y(i)) );
        }

        points = d_data->curveFitter->fitCurve(points);
        size = points.size();

        if ( size == 0 )
            return;

        // Round QwtDoublePoints to QPoints
        // When Qwt support for Qt3 has been dropped (Qwt 6.x)
        // we will use a doubles for painting and the following
        // step will be obsolete.

        polyline.resize(size);

        const QwtDoublePoint *p = points.data();
        QPointF *pl = polyline.data();
        if ( d_data->paintAttributes & PaintFiltered )
        {

            QPointF pp(p[0].x(), p[0].y());
            pl[0] = pp;

            int count = 1;
            for (int i = 1; i < size; i++)
            {
                const QPointF pi(p[i].x(), p[i].y());
                if ( pi != pp )
                {
                    pl[count++] = pi;
                    pp = pi;
                }
            }
            if ( count != size )
                polyline.resize(count);
        }
        else
        {
            for ( int i = 0; i < size; i++ )
            {
                pl[i].setX( p[i].x() );
                pl[i].setY( p[i].y() );
            }
        }
    }
    else
    {
        polyline.resize(size);

        if ( d_data->paintAttributes & PaintFiltered )
        {
            QPointF pp( xMap.xTransform(x(from)), yMap.xTransform(y(from)) );
            polyline[0] = pp;

            int count = 1;
            for (int i = from + 1; i <= to; i++)
            {
                const QPointF pi(xMap.xTransform(x(i)), yMap.xTransform(y(i)));
                if ( pi != pp )
                {
                    polyline[count] = pi;
                    count++;

                    pp = pi;
                }
            }
            if ( count != size )
                polyline.resize(count);
        }
        else
        {
            for (int i = from; i <= to; i++)
            {
                const QPointF pi(xMap.xTransform(x(i)), yMap.xTransform(y(i)));
                polyline[i - from] = pi;
            }
        }
    }

    if ( d_data->paintAttributes & ClipPolygons )
        polyline = QwtClipper::clipPolygonF(painter->window(), polyline);

    QwtPainter::drawPolyline(painter, polyline);

    if ( d_data->brush.style() != Qt::NoBrush )
        fillCurve(painter, xMap, yMap, polyline);
}