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 QwtPainter::drawPolyline(QPainter *painter, const QwtPolygonF &pa)
{
QRect clipRect;
const bool deviceClipping = isClippingNeeded(painter, clipRect);
QwtPolygonF cpa = d_metricsMap.layoutToDevice(pa);
if ( deviceClipping )
cpa = QwtClipper::clipPolygonF(clipRect, cpa);
#if QT_VERSION >= 0x040000
bool doSplit = false;
const QPaintEngine *pe = painter->paintEngine();
if ( pe && pe->type() == QPaintEngine::Raster &&
painter->pen().width() >= 2 )
{
/*
The raster paint engine seems to use some algo with O(n*n).
( Qt 4.3 is better than Qt 4.2, but remains unacceptable)
To work around this problem, we have to split the polygon into
smaller pieces.
*/
doSplit = true;
}
if ( doSplit )
{
const int numPoints = cpa.size();
const QPointF *points = cpa.data();
const int splitSize = 20;
for ( int i = 0; i < numPoints; i += splitSize )
{
const int n = qwtMin(splitSize + 1, cpa.size() - i);
painter->drawPolyline(points + i, n);
}
}
else
#endif
painter->drawPolyline(cpa);
}
/*!
\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));
}
}
//! Sutherland-Hodgman polygon clipping
QwtPolygonF QwtPolygonClipperF::clipPolygon(const QwtPolygonF &pa) const
{
if ( contains( ::boundingRect(pa) ) )
return pa;
QwtPolygonF cpa(pa.size());
clipEdge((Edge)0, pa, cpa);
for ( uint edge = 1; edge < NEdges; edge++ )
{
const QwtPolygonF rpa = cpa;
#if QT_VERSION < 0x040000
cpa.detach();
#endif
clipEdge((Edge)edge, rpa, cpa);
}
return cpa;
}
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);
}
/*!
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);
}
}
static inline QwtDoubleRect boundingRect(const QwtPolygonF &polygon)
{
#if QT_VERSION < 0x040000
if (polygon.isEmpty())
return QwtDoubleRect(0, 0, 0, 0);
register const QwtDoublePoint *pd = polygon.data();
double minx, maxx, miny, maxy;
minx = maxx = pd->x();
miny = maxy = pd->y();
pd++;
for (uint i = 1; i < polygon.size(); i++, pd++)
{
if (pd->x() < minx)
minx = pd->x();
else if (pd->x() > maxx)
maxx = pd->x();
if (pd->y() < miny)
miny = pd->y();
else if (pd->y() > maxy)
maxy = pd->y();
}
return QwtDoubleRect(minx, miny, maxx - minx, maxy - miny);
#else
return polygon.boundingRect();
#endif
}
