// find if a point is in a line
public bool pointInLine(QPointF p, QLineF line)
{
double AB = Math.Abs(line.p1().point.GetDistance(line.p2().point));
double AP = Math.Abs(p.point.GetDistance(line.p1().point));
double PB = Math.Abs(p.point.GetDistance(line.p2().point));
if (Math.Abs(AB - (AP + PB)) < 1.0)
{
return(true);
}
else
{
return(false);
}
}
void SplitEdges(QPolygonF poly, QLineF line)
{
if (SplitPoly != null)
{
SplitPoly.Clear();
}
if (EdgesOnLine != null)
{
EdgesOnLine.Clear();
}
for (int i = 0; i < poly.Count; i++)
{
QLineF edge = new QLineF(poly.ElementAtOrDefault(i), poly.ElementAtOrDefault((i + 1) % poly.Count));
LineSide edgeStartSide = GetSideOfLine(line, edge.p1());
LineSide edgeEndSide = GetSideOfLine(line, edge.p2());
SplitPoly.Add(new PolyEdge(poly[i], edgeStartSide));
// SplitPoly.push_back(PolyEdge{ poly[i], edgeStartSide});
if (edgeStartSide == LineSide.On)
{
EdgesOnLine.Add(SplitPoly.LastOrDefault());
// EdgesOnLine.push_back(&SplitPoly.back());
}
else if (!edgeStartSide.Equals(edgeEndSide) && edgeEndSide != LineSide.On)
{
QPointF ip;
ip = edge.intersect(line);
// assert(res != QLineF::NoIntersection);
if (ip != null)
{
SplitPoly.Add(new PolyEdge(ip, LineSide.On));
// SplitPoly.push_back(PolyEdge{ ip, LineSide::On});
EdgesOnLine.Add(SplitPoly.LastOrDefault());
// EdgesOnLine.Add(&SplitPoly.back());
}
}
}
// connect doubly linked list, except
// first->prev and last->next
for (int ii = 0; ii < (SplitPoly.Count - 1); ii++) // .begin(); iter!=std::prev(SplitPoly.end()); iter++)
// for (auto iter = SplitPoly.begin(); iter != std::prev(SplitPoly.end()); iter++)
{
SplitPoly.ElementAtOrDefault(ii).Next = SplitPoly.ElementAtOrDefault(ii + 1);
SplitPoly.ElementAtOrDefault(ii + 1).Prev = SplitPoly.ElementAtOrDefault(ii);
// auto nextIter = std::next(iter);
// iter.Next = nextIter;
// nextIter->Prev = &(* iter);
}
// connect first->prev and last->next
SplitPoly.LastOrDefault().Next = SplitPoly.FirstOrDefault();
SplitPoly.FirstOrDefault().Prev = SplitPoly.LastOrDefault();
// SplitPoly.back().Next = &SplitPoly.front();
// SplitPoly.front().Prev = &SplitPoly.back();
}
// only support pairs split points
List <QPolygonF> SplitEdges2(QPolygonF poly, QLineF line)
{
if (SplitPoly != null)
{
SplitPoly.Clear();
}
if (EdgesOnLine != null)
{
EdgesOnLine.Clear();
}
// line = new QLineF(new QPointF(new PointLatLngAlt(31.840743072180324, 121.46284818649292)), new QPointF(new PointLatLngAlt(31.840615471377312 , 121.46491885185242)));
for (int i = 0; i < (poly.Count); i++)
{
QLineF edge = new QLineF(poly.ElementAtOrDefault(i), poly.ElementAtOrDefault((i + 1) % poly.Count));
LineSide edgeStartSide = GetSideOfLine(line, edge.p1());
LineSide edgeEndSide = GetSideOfLine(line, edge.p2());
SplitPoly.Add(new PolyEdge(poly[i], edgeStartSide));
// SplitPoly.push_back(PolyEdge{ poly[i], edgeStartSide});
// if (edgeStartSide == LineSide.On)
// {
// EdgesOnLine.Add(SplitPoly.LastOrDefault());
// // EdgesOnLine.push_back(&SplitPoly.back());
// }
// else if (!edgeStartSide.Equals(edgeEndSide) && edgeEndSide != LineSide.On)
if (!edgeStartSide.Equals(edgeEndSide) && edgeEndSide != LineSide.On)
{
QPointF ip;
ip = edge.intersect(line);
// assert(res != QLineF::NoIntersection);
if (ip != null)
{
SplitPoly.Add(new PolyEdge(ip, LineSide.On));
// SplitPoly.push_back(PolyEdge{ ip, LineSide::On});
EdgesOnLine.Add(SplitPoly.LastOrDefault());
// EdgesOnLine.Add(&SplitPoly.back());
}
}
}
int poly_in_split_pair = 0;
List <QPointF> split_pair = new List <QPointF>();
List <QPolygonF> resPolys = new List <QPolygonF>();
// connect doubly linked list and split it into pieces poly
// first->prev and last->next
QPolygonF split_out = new QPolygonF();
QPointF start_point = new QPointF(new PointLatLng());
QPointF end_point = new QPointF(new PointLatLng());
int ii = 0;
for (ii = 0; ii < (SplitPoly.Count); ii++) // .begin(); iter!=std::prev(SplitPoly.end()); iter++)
// for (auto iter = SplitPoly.begin(); iter != std::prev(SplitPoly.end()); iter++)
{
if (SplitPoly.ElementAtOrDefault(ii).StartSide != LineSide.On) // normal points
{
QPointF qp_added = new QPointF(new PointLatLng(SplitPoly.ElementAtOrDefault(ii).StartPos.x(), SplitPoly.ElementAtOrDefault(ii).StartPos.y()));
split_out.Add(qp_added);
}
else // edge points
{
if (0 == (poly_in_split_pair %= 2)) // new start point, then find out the end point
{
poly_in_split_pair = 0;
QPolygonF split_out2 = new QPolygonF(); // 2nd poly
// add start point
start_point = new QPointF(new PointLatLng(SplitPoly.ElementAtOrDefault(ii).StartPos.x(), SplitPoly.ElementAtOrDefault(ii).StartPos.y()));
split_out.Add(start_point);
split_out2.Add(start_point);
// find next split point to 1st poly
// SplitPoly.ElementAtOrDefault(ii - 1).Next = SplitPoly.ElementAtOrDefault(ii);
bool collect_pnt = false;
for (int jj = ii + 1; jj < (SplitPoly.Count); jj++) // .begin(); iter!=std::prev(SplitPoly.end()); iter++)
{
if (collect_pnt)
{
QPointF qp_added = new QPointF(new PointLatLng(SplitPoly.ElementAtOrDefault(jj).StartPos.x(), SplitPoly.ElementAtOrDefault(jj).StartPos.y()));
split_out.Add(qp_added);
}
else if (SplitPoly.ElementAtOrDefault(jj).StartSide == LineSide.On) // end points
{
end_point = new QPointF(new PointLatLng(SplitPoly.ElementAtOrDefault(jj).StartPos.x(), SplitPoly.ElementAtOrDefault(jj).StartPos.y()));
split_out.Add(end_point);
// split_out2.Add(qp_added);
collect_pnt = true;
}
else // 2nd poly
{
QPointF qp_added = new QPointF(new PointLatLng(SplitPoly.ElementAtOrDefault(jj).StartPos.x(), SplitPoly.ElementAtOrDefault(jj).StartPos.y()));
split_out2.Add(qp_added);
}
}
resPolys.Add(split_out);
split_out2.Add(end_point);
resPolys.Add(split_out2);
start_point = new QPointF(new PointLatLng());
end_point = new QPointF(new PointLatLng());
split_out = new QPolygonF();
split_out2 = new QPolygonF();
}
poly_in_split_pair++;
}
// auto nextIter = std::next(iter);
// iter.Next = nextIter;
// nextIter->Prev = &(* iter);
}
// add last poly
// resPolys.Add(split_out);
return(resPolys);
}
static double CalcSignedDistance(QLineF line, QPointF p)
{
// scalar projection on line. in case of co-linear
// vectors this is equal to the signed distance.
return((p.x() - line.p1().x()) * (line.p2().x() - line.p1().x()) + (p.y() - line.p1().y()) * (line.p2().y() - line.p1().y()));
}
static LineSide GetSideOfLine(QLineF line, QPointF pt)
{
double d = (pt.x() - line.p1().x()) * (line.p2().y() - line.p1().y()) - (pt.y() - line.p1().y()) * (line.p2().x() - line.p1().x());
return((Math.Sign(d) >= 0) ? LineSide.Right : ((Math.Sign(d) < 0) ? LineSide.Left : LineSide.On));
}