private static void AssignInteriorRings([NotNull] IEnumerable <Linestring> interiorRings,
[NotNull] IList <RingGroup> leftPolys,
[NotNull] IList <RingGroup> rightPolys,
[NotNull] IList <RingGroup> bothSidePolys,
[NotNull] MultiLinestring unCutParts,
double tolerance)
{
foreach (Linestring unCutIsland in interiorRings)
{
// Assuming no conflicts (island within island) between un-cut islands because
// they all come from the same source.
int assignmentCount = 0;
assignmentCount +=
AssignInteriorRing(unCutIsland, rightPolys, tolerance);
assignmentCount +=
AssignInteriorRing(unCutIsland, leftPolys, tolerance);
assignmentCount +=
AssignInteriorRing(unCutIsland, bothSidePolys, tolerance);
if (assignmentCount == 0)
{
unCutParts.AddLinestring(unCutIsland);
}
Assert.True(assignmentCount < 2, "Multiple inner ring assignments!");
}
}
public MultipleRingNavigator([NotNull] MultiLinestring sourceRings,
[NotNull] MultiLinestring targets,
double tolerance,
bool allowTargetTargetIntersections = false)
: base(sourceRings, targets, tolerance)
{
Assert.ArgumentCondition(sourceRings.IsClosed, "Source rings must be closed.");
// TODO: Implement target-self-intersecting navigation (vertical, spaghetti, multipatch rings,
// and especially simplified self-intersecting lines)
// TODO: Implement Reshape and avoid phantom points
_allowTargetTargetIntersections = allowTargetTargetIntersections;
}
private static void AssignInteriorRings([NotNull] IEnumerable <Linestring> interiorRings,
[NotNull] ICollection <RingGroup> polygons,
[NotNull] MultiLinestring unassignedParts,
double tolerance)
{
foreach (Linestring interiorRing in interiorRings)
{
// Assuming no conflicts (island within island) between un-cut islands because
// they all come from the same source.
int assignmentCount =
AssignInteriorRing(interiorRing, polygons, tolerance);
if (assignmentCount == 0)
{
unassignedParts.AddLinestring(interiorRing);
}
Assert.True(assignmentCount < 2, "Multiple inner ring assignments!");
}
}
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);
}
/// <summary>
/// Cuts the source ring using the target and returns separate lists
/// of result rings on the left/right side of the cut line.
/// </summary>
/// <param name="leftPolys">Result polygons on the left side of the cut line.</param>
/// <param name="rightPolys">Result polygons on the right side of the cut line.</param>
/// <param name="clipPolys"></param>
/// <param name="undefinedSidePolys"></param>
/// <param name="unCutParts"></param>
/// <returns>Whether the cut operation was successful or not.</returns>
public bool CutXY([NotNull] out IList <RingGroup> leftPolys,
[NotNull] out IList <RingGroup> rightPolys,
[NotNull] out IList <RingGroup> clipPolys,
[NotNull] out IList <MultiLinestring> undefinedSidePolys,
[NotNull] out MultiLinestring unCutParts)
{
Assert.ArgumentCondition(_subcurveNavigator.Source.IsClosed, "source must be closed.");
// Based on Weiler–Atherton clipping algorithm, added specific logic for
// linear intersections, un-closed target lines and multi-parts.
// Potential enhancements: Do not insert phantom points!
IList <Linestring> rightRings = GetRightSideRings();
IList <Linestring> leftRings = GetLeftSideRings();
IList <Linestring> duplicates = new List <Linestring>();
if (!_subcurveNavigator.Target.IsClosed &&
_subcurveNavigator.AreIntersectionPointsNonSequential())
{
// Cut backs result in duplicates which are both on the left and the right!
duplicates = RemoveDuplicateRings(leftRings, rightRings);
}
// Assign the cut inner rings (anti-clockwise) to un-cut outer rings...
var unCutOuterRings = _subcurveNavigator.GetNonIntersectedSourceRings()
.Where(r => r.ClockwiseOriented != false)
.ToList();
rightPolys = AssignToResultRingGroups(rightRings, unCutOuterRings);
leftPolys = AssignToResultRingGroups(leftRings, unCutOuterRings);
IList <RingGroup> bothSidePolys = AssignToResultRingGroups(duplicates, unCutOuterRings);
unCutParts =
unCutOuterRings.Count == 1
? (MultiLinestring) new RingGroup(unCutOuterRings[0])
: new MultiPolycurve(unCutOuterRings);
// Assign the remaining interior rings;
AssignInteriorRings(rightRings, leftPolys, rightPolys, bothSidePolys, unCutParts,
_subcurveNavigator.Tolerance);
AssignInteriorRings(leftRings, leftPolys, rightPolys, bothSidePolys, unCutParts,
_subcurveNavigator.Tolerance);
AssignInteriorRings(duplicates, leftPolys, rightPolys, bothSidePolys, unCutParts,
_subcurveNavigator.Tolerance);
// Assign the inner rings from the original
var unCutIslands = _subcurveNavigator.GetNonIntersectedSourceRings()
.Where(r => r.ClockwiseOriented == false);
AssignInteriorRings(unCutIslands, leftPolys, rightPolys, bothSidePolys, unCutParts,
_subcurveNavigator.Tolerance);
// Assign closed cut lines completely contained by an outer ring (and not by an inner ring)
var unusedCutRings =
_subcurveNavigator.GetNonIntersectedTargets().Where(t => t.IsClosed);
undefinedSidePolys = bothSidePolys.Cast <MultiLinestring>().ToList();
clipPolys = new List <RingGroup>();
foreach (Linestring unusedCutRing in unusedCutRings)
{
MultiLinestring updatedUnCut;
RingGroup cookie;
if (!unCutParts.IsEmpty &&
TryCutCookie(unusedCutRing, unCutParts, out updatedUnCut, out cookie))
{
unCutParts = MultiPolycurve.CreateEmpty();
undefinedSidePolys.Add(updatedUnCut);
clipPolys.Add(cookie);
continue;
}
RingGroup updatedCut;
if (TryCutCookie(unusedCutRing, leftPolys, out updatedCut, out cookie))
{
clipPolys.Add(cookie);
continue;
}
if (TryCutCookie(unusedCutRing, rightPolys, out updatedCut, out cookie))
{
clipPolys.Add(cookie);
continue;
}
if (TryCutCookie(unusedCutRing, bothSidePolys, out updatedCut, out cookie))
{
clipPolys.Add(cookie);
}
}
return((rightPolys.Count > 0 && leftPolys.Count > 0) ||
undefinedSidePolys.Count > 1 || clipPolys.Count > 0);
}