private static int AssignInteriorRing([NotNull] Linestring interiorRing,
IEnumerable <RingGroup> resultPolys,
double tolerance)
{
int assignmentCount = 0;
foreach (RingGroup resultPoly in resultPolys)
{
if (GeomRelationUtils.PolycurveContainsXY(
resultPoly.ExteriorRing, interiorRing.StartPoint, tolerance))
{
resultPoly.AddInteriorRing(interiorRing);
assignmentCount++;
}
}
return(assignmentCount);
}
/// <summary>
/// Creates the list of result ring groups from the processed inner/outer rings and the
/// unprocessed outer rings by:
/// - Adding processed outer rings to the output and remove them from the input collection
/// - For each processed inner rings, that is contained in an un-processed outer ring:
/// - Add the unprocessed outer ring together with the inner ring to the result.
/// - Remove both the unprocessed outer and the inner ring from the respective input collection.
/// </summary>
/// <param name="processedResultRings"></param>
/// <param name="unprocessedOuterRings"></param>
/// <returns></returns>
private IList <RingGroup> AssignToResultRingGroups(
ICollection <Linestring> processedResultRings,
ICollection <Linestring> unprocessedOuterRings)
{
var result = new List <RingGroup>();
foreach (Linestring processedResultRing in processedResultRings.ToList())
{
if (processedResultRing.ClockwiseOriented != false)
{
result.Add(new RingGroup(processedResultRing));
processedResultRings.Remove(processedResultRing);
}
else
{
// Intersected (processed) inner rings:
// Find the containing un-cut outer ring, assign and remove from un-processed list
Linestring containing = unprocessedOuterRings.FirstOrDefault(
o => o.ClockwiseOriented == true &&
GeomRelationUtils.PolycurveContainsXY(
o, processedResultRing.StartPoint, _subcurveNavigator.Tolerance));
if (containing != null)
{
unprocessedOuterRings.Remove(containing);
// Add at the beginning to boost performance, assuming a few (or one) large rings contains everything
result.Insert(0, new RingGroup(containing, new[] { processedResultRing }));
// remove from the list, the remaining inner rings will be assigned afterwards;
processedResultRings.Remove(processedResultRing);
}
}
}
return(result);
}
private static bool TryCutCookie <T>([NotNull] T polygon,
[NotNull] Linestring cookieCutter,
double tolerance,
out RingGroup resultCookie,
bool allowEmptyResults = false)
where T : MultiLinestring
{
resultCookie = null;
if (!GeomRelationUtils.PolycurveContainsXY(
polygon, cookieCutter, tolerance))
{
return(false);
}
// Remove pre-existing interior rings that are completely within cookie cutter
List <Linestring> containedExistingIslands =
RemoveContainedExistingIslands(polygon, cookieCutter, tolerance);
Linestring interiorRing = cookieCutter.Clone();
Assert.True(interiorRing.IsClosed, "Interior ring is not closed");
interiorRing.TryOrientAnticlockwise();
IntersectionPoint3D outerRingIntersection;
bool ringsAreEqual;
int parentRingIdx = GetContainingRingIndex(
polygon, interiorRing, tolerance, out ringsAreEqual, out outerRingIntersection);
Assert.False(parentRingIdx < 0, "No parent ring found");
Linestring containingRing = polygon.GetLinestring(parentRingIdx);
if (containingRing.ClockwiseOriented == false)
{
// The cutter is completely within an existing island -> ignore (keep existing ring)
return(false);
}
if (ringsAreEqual)
{
// The cutter is equal to the found ring. Positive rings cancel each other out:
if (!allowEmptyResults)
{
return(false);
}
polygon.RemoveLinestring(containingRing);
}
else if (outerRingIntersection == null)
{
// The cutter is completely within an existing outer ring -> add as island
polygon.AddLinestring(interiorRing);
}
else
{
// create boundary loop:
polygon.RemoveLinestring(containingRing);
Linestring withBoundaryLoop = CreateWithBoundaryLoop(containingRing, interiorRing,
outerRingIntersection,
tolerance);
polygon.InsertLinestring(parentRingIdx, withBoundaryLoop);
}
resultCookie = RingGroup.CreateProperlyOriented(cookieCutter.Clone());
foreach (Linestring unusedCutRing in containedExistingIslands)
{
RingGroup cookieInCookie;
Assert.True(TryCutCookie(resultCookie, unusedCutRing, tolerance,
out cookieInCookie),
"Inner ring in cookie cutter cannot be cut from result cookie");
}
return(true);
}