internal virtual bool NextPath_()
{
if (!m_b_paths)
{
if (!m_seg_iter.NextPath())
{
m_b_done = true;
return(false);
}
m_function = com.epl.geometry.PairwiseIntersectorImpl.State.nextSegment;
return(true);
}
if (--m_path_index == -1)
{
m_b_done = true;
return(false);
}
if (m_b_swap_elements)
{
m_multi_path_impl_b.QueryPathEnvelope2D(m_path_index, m_paths_query);
}
else
{
m_multi_path_impl_a.QueryPathEnvelope2D(m_path_index, m_paths_query);
}
m_qt_iter.ResetIterator(m_paths_query, m_tolerance);
m_function = com.epl.geometry.PairwiseIntersectorImpl.State.iterate;
return(true);
}
internal virtual com.epl.geometry.Geometry TryFastIntersectPolylinePolygon_(com.epl.geometry.Polyline polyline, com.epl.geometry.Polygon polygon)
{
com.epl.geometry.MultiPathImpl polylineImpl = (com.epl.geometry.MultiPathImpl)polyline._getImpl();
com.epl.geometry.MultiPathImpl polygonImpl = (com.epl.geometry.MultiPathImpl)polygon._getImpl();
double tolerance = com.epl.geometry.InternalUtils.CalculateToleranceFromGeometry(m_spatial_reference, polygon, false);
com.epl.geometry.Envelope2D clipEnvelope = new com.epl.geometry.Envelope2D();
{
polygonImpl.QueryEnvelope2D(clipEnvelope);
com.epl.geometry.Envelope2D env1 = new com.epl.geometry.Envelope2D();
polylineImpl.QueryEnvelope2D(env1);
env1.Inflate(2.0 * tolerance, 2.0 * tolerance);
clipEnvelope.Intersect(env1);
System.Diagnostics.Debug.Assert((!clipEnvelope.IsEmpty()));
}
clipEnvelope.Inflate(10 * tolerance, 10 * tolerance);
if (true)
{
double tol = 0;
com.epl.geometry.Geometry clippedPolyline = com.epl.geometry.Clipper.Clip(polyline, clipEnvelope, tol, 0.0);
polyline = (com.epl.geometry.Polyline)clippedPolyline;
polylineImpl = (com.epl.geometry.MultiPathImpl)polyline._getImpl();
}
com.epl.geometry.AttributeStreamOfInt32 clipResult = new com.epl.geometry.AttributeStreamOfInt32(0);
int unresolvedSegments = -1;
com.epl.geometry.GeometryAccelerators accel = polygonImpl._getAccelerators();
if (accel != null)
{
com.epl.geometry.RasterizedGeometry2D rgeom = accel.GetRasterizedGeometry();
if (rgeom != null)
{
unresolvedSegments = 0;
clipResult.Reserve(polylineImpl.GetPointCount() + polylineImpl.GetPathCount());
com.epl.geometry.Envelope2D seg_env = new com.epl.geometry.Envelope2D();
com.epl.geometry.SegmentIteratorImpl iter = polylineImpl.QuerySegmentIterator();
while (iter.NextPath())
{
while (iter.HasNextSegment())
{
com.epl.geometry.Segment seg = iter.NextSegment();
seg.QueryEnvelope2D(seg_env);
com.epl.geometry.RasterizedGeometry2D.HitType hit = rgeom.QueryEnvelopeInGeometry(seg_env);
if (hit == com.epl.geometry.RasterizedGeometry2D.HitType.Inside)
{
clipResult.Add(1);
}
else
{
if (hit == com.epl.geometry.RasterizedGeometry2D.HitType.Outside)
{
clipResult.Add(0);
}
else
{
clipResult.Add(-1);
unresolvedSegments++;
}
}
}
}
}
}
if (polygon.GetPointCount() > 5)
{
double tol = 0;
com.epl.geometry.Geometry clippedPolygon = com.epl.geometry.Clipper.Clip(polygon, clipEnvelope, tol, 0.0);
polygon = (com.epl.geometry.Polygon)clippedPolygon;
polygonImpl = (com.epl.geometry.MultiPathImpl)polygon._getImpl();
accel = polygonImpl._getAccelerators();
}
//update accelerators
if (unresolvedSegments < 0)
{
unresolvedSegments = polylineImpl.GetSegmentCount();
}
// Some heuristics to decide if it makes sense to go with fast intersect
// vs going with the regular planesweep.
double totalPoints = (double)(polylineImpl.GetPointCount() + polygonImpl.GetPointCount());
double thisAlgorithmComplexity = ((double)unresolvedSegments * polygonImpl.GetPointCount());
// assume the worst case.
double planesweepComplexity = System.Math.Log(totalPoints) * totalPoints;
double empiricConstantFactorPlaneSweep = 4;
if (thisAlgorithmComplexity > planesweepComplexity * empiricConstantFactorPlaneSweep)
{
// Based on the number of input points, we deduced that the
// plansweep performance should be better than the brute force
// performance.
return null;
}
// resort to planesweep if quadtree does not help
com.epl.geometry.QuadTreeImpl polygonQuadTree = null;
com.epl.geometry.SegmentIteratorImpl polygonIter = polygonImpl.QuerySegmentIterator();
// Some logic to decide if it makes sense to build a quadtree on the
// polygon segments
if (accel != null && accel.GetQuadTree() != null)
{
polygonQuadTree = accel.GetQuadTree();
}
if (polygonQuadTree == null && polygonImpl.GetPointCount() > 20)
{
polygonQuadTree = com.epl.geometry.InternalUtils.BuildQuadTree(polygonImpl);
}
com.epl.geometry.Polyline result_polyline = (com.epl.geometry.Polyline)polyline.CreateInstance();
com.epl.geometry.MultiPathImpl resultPolylineImpl = (com.epl.geometry.MultiPathImpl)result_polyline._getImpl();
com.epl.geometry.QuadTreeImpl.QuadTreeIteratorImpl qIter = null;
com.epl.geometry.SegmentIteratorImpl polylineIter = polylineImpl.QuerySegmentIterator();
double[] @params = new double[9];
com.epl.geometry.AttributeStreamOfDbl intersections = new com.epl.geometry.AttributeStreamOfDbl(0);
com.epl.geometry.SegmentBuffer segmentBuffer = new com.epl.geometry.SegmentBuffer();
int start_index = -1;
int inCount = 0;
int segIndex = 0;
bool bOptimized = clipResult.Size() > 0;
// The algorithm is like that:
// Loop through all the segments of the polyline.
// For each polyline segment, intersect it with each of the polygon
// segments.
// If no intersections found then,
// If the polyline segment is completely inside, it is added to the
// result polyline.
// If it is outside, it is thrown out.
// If it intersects, then cut the polyline segment to pieces and test
// each part of the intersected result.
// The cut pieces will either have one point inside, or one point
// outside, or the middle point inside/outside.
//
int polylinePathIndex = -1;
while (polylineIter.NextPath())
{
polylinePathIndex = polylineIter.GetPathIndex();
int stateNewPath = 0;
int stateAddSegment = 1;
int stateManySegments = 2;
int stateManySegmentsContinuePath = 2;
int stateManySegmentsNewPath = 3;
int state = stateNewPath;
start_index = -1;
inCount = 0;
while (polylineIter.HasNextSegment())
{
int clipStatus = bOptimized ? (int)clipResult.Get(segIndex) : -1;
segIndex++;
com.epl.geometry.Segment polylineSeg = polylineIter.NextSegment();
if (clipStatus < 0)
{
System.Diagnostics.Debug.Assert((clipStatus == -1));
// Analyse polyline segment for intersection with the
// polygon.
if (polygonQuadTree != null)
{
if (qIter == null)
{
qIter = polygonQuadTree.GetIterator(polylineSeg, tolerance);
}
else
{
qIter.ResetIterator(polylineSeg, tolerance);
}
int path_index = -1;
for (int ind = qIter.Next(); ind != -1; ind = qIter.Next())
{
polygonIter.ResetToVertex(polygonQuadTree.GetElement(ind));
// path_index
path_index = polygonIter.GetPathIndex();
com.epl.geometry.Segment polygonSeg = polygonIter.NextSegment();
// intersect polylineSeg and polygonSeg.
int count = polylineSeg.Intersect(polygonSeg, null, @params, null, tolerance);
for (int i = 0; i < count; i++)
{
intersections.Add(@params[i]);
}
}
}
else
{
// no quadtree built
polygonIter.ResetToFirstPath();
while (polygonIter.NextPath())
{
while (polygonIter.HasNextSegment())
{
com.epl.geometry.Segment polygonSeg = polygonIter.NextSegment();
// intersect polylineSeg and polygonSeg.
int count = polylineSeg.Intersect(polygonSeg, null, @params, null, tolerance);
for (int i = 0; i < count; i++)
{
intersections.Add(@params[i]);
}
}
}
}
if (intersections.Size() > 0)
{
// intersections detected.
intersections.Sort(0, intersections.Size());
// std::sort(intersections.begin(),
// intersections.end());
double t0 = 0;
intersections.Add(1.0);
int status = -1;
for (int i = 0, n = intersections.Size(); i < n; i++)
{
double t = intersections.Get(i);
if (t == t0)
{
continue;
}
bool bWholeSegment = false;
com.epl.geometry.Segment resSeg;
if (t0 != 0 || t != 1.0)
{
polylineSeg.Cut(t0, t, segmentBuffer);
resSeg = segmentBuffer.Get();
}
else
{
resSeg = polylineSeg;
bWholeSegment = true;
}
if (state >= stateManySegments)
{
resultPolylineImpl.AddSegmentsFromPath(polylineImpl, polylinePathIndex, start_index, inCount, state == stateManySegmentsNewPath);
if (AnalyseClipSegment_(polygon, resSeg.GetStartXY(), tolerance) != 1)
{
if (AnalyseClipSegment_(polygon, resSeg, tolerance) != 1)
{
return null;
}
}
//someting went wrong we'll falback to slower but robust planesweep code.
resultPolylineImpl.AddSegment(resSeg, false);
state = stateAddSegment;
inCount = 0;
}
else
{
status = AnalyseClipSegment_(polygon, resSeg, tolerance);
switch (status)
{
case 1:
{
if (!bWholeSegment)
{
resultPolylineImpl.AddSegment(resSeg, state == stateNewPath);
state = stateAddSegment;
}
else
{
if (state < stateManySegments)
{
start_index = polylineIter.GetStartPointIndex() - polylineImpl.GetPathStart(polylinePathIndex);
inCount = 1;
if (state == stateNewPath)
{
state = stateManySegmentsNewPath;
}
else
{
System.Diagnostics.Debug.Assert((state == stateAddSegment));
state = stateManySegmentsContinuePath;
}
}
else
{
inCount++;
}
}
break;
}
case 0:
{
state = stateNewPath;
start_index = -1;
inCount = 0;
break;
}
default:
{
return null;
}
}
}
// may happen if a segment
// coincides with the border.
t0 = t;
}
}
else
{
clipStatus = AnalyseClipSegment_(polygon, polylineSeg.GetStartXY(), tolerance);
// simple
// case
// no
// intersection.
// Both
// points
// must
// be
// inside.
if (clipStatus < 0)
{
System.Diagnostics.Debug.Assert((clipStatus >= 0));
return null;
}
// something goes wrong, resort to
// planesweep
System.Diagnostics.Debug.Assert((AnalyseClipSegment_(polygon, polylineSeg.GetEndXY(), tolerance) == clipStatus));
if (clipStatus == 1)
{
// the whole segment inside
if (state < stateManySegments)
{
System.Diagnostics.Debug.Assert((inCount == 0));
start_index = polylineIter.GetStartPointIndex() - polylineImpl.GetPathStart(polylinePathIndex);
if (state == stateNewPath)
{
state = stateManySegmentsNewPath;
}
else
{
System.Diagnostics.Debug.Assert((state == stateAddSegment));
state = stateManySegmentsContinuePath;
}
}
inCount++;
}
else
{
System.Diagnostics.Debug.Assert((state < stateManySegments));
start_index = -1;
inCount = 0;
}
}
intersections.Clear(false);
}
else
{
// clip status is determined by other means
if (clipStatus == 0)
{
// outside
System.Diagnostics.Debug.Assert((AnalyseClipSegment_(polygon, polylineSeg, tolerance) == 0));
System.Diagnostics.Debug.Assert((start_index < 0));
System.Diagnostics.Debug.Assert((inCount == 0));
continue;
}
if (clipStatus == 1)
{
System.Diagnostics.Debug.Assert((AnalyseClipSegment_(polygon, polylineSeg, tolerance) == 1));
if (state == stateNewPath)
{
state = stateManySegmentsNewPath;
start_index = polylineIter.GetStartPointIndex() - polylineImpl.GetPathStart(polylinePathIndex);
}
else
{
if (state == stateAddSegment)
{
state = stateManySegmentsContinuePath;
start_index = polylineIter.GetStartPointIndex() - polylineImpl.GetPathStart(polylinePathIndex);
}
else
{
System.Diagnostics.Debug.Assert((state >= stateManySegments));
}
}
inCount++;
continue;
}
}
}
if (state >= stateManySegments)
{
resultPolylineImpl.AddSegmentsFromPath(polylineImpl, polylinePathIndex, start_index, inCount, state == stateManySegmentsNewPath);
start_index = -1;
}
}
return result_polyline;
}