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);
}
/*!
Fill the area between the curve and the baseline with
the curve brush
\param painter Painter
\param xMap x map
\param yMap y map
\param pa Polygon
\sa setBrush(), setBaseline(), setCurveType()
*/
void QwtPlotCurve::fillCurve(QPainter *painter,
const QwtScaleMap &xMap, const QwtScaleMap &yMap,
QwtPolygonF &pa) const
{
if ( d_data->brush.style() == Qt::NoBrush )
return;
closePolyline(xMap, yMap, pa);
if ( pa.count() <= 2 ) // a line can't be filled
return;
QBrush b = d_data->brush;
if ( !b.color().isValid() )
b.setColor(d_data->pen.color());
painter->save();
painter->setPen(QPen(Qt::NoPen));
painter->setBrush(b);
QwtPainter::drawPolygon(painter, pa);
painter->restore();
}