private static List <Linestring> RemoveContainedExistingIslands <T>(
[NotNull] T fromPolygon,
[NotNull] Linestring cookieCutter,
double tolerance) where T : MultiLinestring
{
List <Linestring> existingInnerRings = fromPolygon
.GetLinestrings()
.Where(l => l.ClockwiseOriented == false)
.ToList();
Assert.NotNull(cookieCutter.ClockwiseOriented);
var containedExistingIslands = new List <Linestring>();
foreach (Linestring existingInnerRing in existingInnerRings)
{
bool?islandWithinCookie = GeomRelationUtils.AreaContainsXY(
cookieCutter, existingInnerRing.StartPoint, tolerance, true);
// TODO: handle the case where the inner ring touches cutter in StartPoint
if (islandWithinCookie == true)
{
containedExistingIslands.Add(existingInnerRing);
fromPolygon.RemoveLinestring(existingInnerRing);
}
}
return(containedExistingIslands);
}
/// <summary>
/// Returns source rings disjoint from target and target rings disjoint from source.
/// </summary>
/// <param name="ringPredicate"></param>
/// <returns></returns>
private IEnumerable <Linestring> GetRingsDisjointFromOtherPoly(
Predicate <Linestring> ringPredicate)
{
var result = new List <Linestring>();
// W.r.t. AreaContainsXY returning null: if the start point is on the boundary there
// are duplicate rings which need to be identified elsewhere.
ISegmentList target = _subcurveNavigator.Target;
foreach (Linestring ring in _subcurveNavigator.GetNonIntersectedSourceRings()
.Where(r => ringPredicate(r)))
{
bool?contains = GeomRelationUtils.AreaContainsXY(
target, ring.StartPoint, _subcurveNavigator.Tolerance);
if (contains == false)
{
// disjoint
result.Add(ring);
}
}
ISegmentList source = _subcurveNavigator.Source;
foreach (Linestring ring in _subcurveNavigator.GetNonIntersectedTargets()
.Where(r => ringPredicate(r)))
{
bool?contains = GeomRelationUtils.AreaContainsXY(
source, ring.StartPoint, _subcurveNavigator.Tolerance);
if (contains == false)
{
result.Add(ring);
}
}
return(result);
}
private static int GetContainingRingIndex([NotNull] MultiLinestring polygon,
[NotNull] Linestring containedRing,
double tolerance,
out bool ringsAreEqual,
out IntersectionPoint3D touchPoint)
{
IList <IntersectionPoint3D> intersectionPoints =
GeomTopoOpUtils.GetIntersectionPoints(polygon, containedRing, tolerance);
ringsAreEqual = false;
touchPoint = null;
// Equal to outer ring -> removes outer ring in original
// or equal to inner ring -> ignore cookie cutter
if (intersectionPoints.Count == 2 &&
intersectionPoints[0].SourcePartIndex == intersectionPoints[1].SourcePartIndex &&
intersectionPoints[0].Point.Equals(intersectionPoints[1].Point) &&
intersectionPoints[0].Type == IntersectionPointType.LinearIntersectionStart &&
intersectionPoints[1].Type == IntersectionPointType.LinearIntersectionEnd)
{
ringsAreEqual = true;
return(intersectionPoints[0].SourcePartIndex);
}
var outerRingIntersections =
intersectionPoints
.Where(i => polygon.GetLinestring(i.SourcePartIndex).ClockwiseOriented == true)
.ToList();
// Touching outer ring in one point -> boundary loop in original
if (outerRingIntersections.Count > 0)
{
Assert.True(outerRingIntersections.Count < 2,
"Unexpected number of touching points.");
touchPoint = outerRingIntersections[0];
return(touchPoint.SourcePartIndex);
}
// Inside an inner ring -> ignore cookie cutter
for (int i = 0; i < polygon.PartCount; i++)
{
Linestring ring = polygon.GetLinestring(i);
if (ring.ClockwiseOriented == true)
{
continue;
}
int currentIdx = i;
bool?areaContainsXY = GeomRelationUtils.AreaContainsXY(
ring, containedRing,
intersectionPoints.Where(ip => ip.SourcePartIndex == currentIdx),
tolerance, true);
if (areaContainsXY == true)
{
return(i);
}
}
// Inside an outer ring but not an inner ring: Add as island
for (int i = 0; i < polygon.PartCount; i++)
{
Linestring ring = polygon.GetLinestring(i);
if (ring.ClockwiseOriented == false)
{
continue;
}
if (GeomRelationUtils.AreaContainsXY(ring, containedRing.StartPoint,
tolerance) == true)
{
return(i);
}
}
return(-1);
}
