private static IList <IGeometry> TryCutRingGroups(
IPolygon inputPolygon,
IPolyline cutPolyline,
ChangeAlongZSource zSource)
{
// TODO:
// In order to avoid the arbitrary grouping of multipart polygons, try to apply left/right logic
// provided by GeomTopoOpUtils
var existingFeature = new List <IPolygon>();
var newFeatures = new List <IPolygon>();
var cutResultsPerConnectedComponent =
TryCutConnectedComponents(inputPolygon, cutPolyline, zSource);
foreach (IList <RingGroup> cutRingGroups in cutResultsPerConnectedComponent)
{
IRing ringTemplate = GeometryFactory.CreateEmptyRing(inputPolygon);
var cutResults =
cutRingGroups.Select(
rg =>
GeometryConversionUtils.CreatePolygon(
inputPolygon, ringTemplate, rg))
.ToList();
var largest = GeometryUtils.GetLargestGeometry(cutResults);
foreach (IPolygon cutComponent in cutResults)
{
if (cutComponent == largest)
{
existingFeature.Add(cutComponent);
}
else
{
newFeatures.Add(cutComponent);
}
}
}
if (newFeatures.Count == 0)
{
// no cut happened:
return(null);
}
var result = new List <IGeometry>
{
GeometryUtils.Union(existingFeature)
};
result.AddRange(newFeatures.Cast <IGeometry>());
return(result);
}
private static Dictionary <IPolygon, IMultiPatch> BuildResultMultipatches(
[NotNull] IMultiPatch prototype,
[NotNull] IDictionary <RingGroup, List <RingGroup> > splitResultsByFootprintPart,
DegenerateMultipatchFootprintAction nonSimpleBoundaryAction)
{
var result = new Dictionary <IPolygon, IMultiPatch>();
IRing emptyRing = GeometryFactory.CreateEmptyRing(prototype);
foreach (var outerRingsByFootprintPart in splitResultsByFootprintPart)
{
RingGroup footprintPart = outerRingsByFootprintPart.Key;
List <RingGroup> resultPolys = outerRingsByFootprintPart.Value;
IMultiPatch resultMultipatch =
GeometryFactory.CreateEmptyMultiPatch(prototype);
foreach (RingGroup poly in resultPolys)
{
// TODO: Support vertical ring group with inner rings
bool simplify = poly.InteriorRings.Any();
GeometryConversionUtils.AddRingGroup(
resultMultipatch, poly, simplify, poly.Id != null);
}
if (resultPolys.Any(p => p.Id != null))
{
GeometryUtils.MakePointIDAware(resultMultipatch);
}
// Guard against multipatches with wrong footprint. They are so broken (IRelationalOps are wrong) that
// it's not worth using them any further...
if (IsMultipatchWithDegenerateFootprint(resultMultipatch))
{
switch (nonSimpleBoundaryAction)
{
case DegenerateMultipatchFootprintAction.Throw:
throw new DegenerateResultGeometryException(
"The multipatch cut operation resulted in a multipatch with degenerate footprint.");
case DegenerateMultipatchFootprintAction.Discard:
_msg.DebugFormat(
"Discarding result multipatch with degenerate boundary: {0}",
GeometryUtils.ToString(resultMultipatch));
continue;
case DegenerateMultipatchFootprintAction.Keep:
_msg.DebugFormat(
"Detected result multipatch with degenerate boundary (it will be kept): {0}",
GeometryUtils.ToString(resultMultipatch));
break;
}
}
IPolygon footprintPoly =
GeometryConversionUtils.CreatePolygon(emptyRing, emptyRing, footprintPart);
result.Add(footprintPoly, resultMultipatch);
}
return(result);
}
private static IList <IGeometry> TryCutXY(
IPolygon inputPolygon,
IPolyline cutPolyline,
ChangeAlongZSource zSource)
{
// TODO:
// In order to avoid the arbitrary grouping of multipart polygons, try to apply left/right logic
// provided by GeomTopoOpUtils
double tolerance = GeometryUtils.GetXyTolerance(inputPolygon);
double zTolerance = GeometryUtils.GetZTolerance(inputPolygon);
MultiPolycurve inputMultipoly =
GeometryConversionUtils.CreateMultiPolycurve(inputPolygon);
var cutLine = GeometryFactory.Clone(cutPolyline);
if (GeometryUtils.IsZAware(cutLine) &&
zSource != ChangeAlongZSource.Target)
{
((IZAware)cutLine).DropZs();
}
Plane3D plane = null;
if (zSource == ChangeAlongZSource.SourcePlane)
{
plane = ChangeAlongZUtils.GetSourcePlane(
inputMultipoly.GetPoints().ToList(), zTolerance);
}
GeometryUtils.Simplify(cutLine, true, true);
MultiPolycurve cutLinestrings = GeometryConversionUtils.CreateMultiPolycurve(cutLine);
bool isMultipart = GeometryUtils.GetExteriorRingCount(inputPolygon) > 1;
IList <MultiLinestring> resultGeoms =
GeomTopoOpUtils.CutXY(inputMultipoly, cutLinestrings, tolerance, !isMultipart);
var result = new List <IGeometry>();
foreach (MultiLinestring resultPoly in resultGeoms)
{
if (plane != null)
{
resultPoly.AssignUndefinedZs(plane);
}
else
{
resultPoly.InterpolateUndefinedZs();
}
result.Add(GeometryConversionUtils.CreatePolygon(inputPolygon,
resultPoly.GetLinestrings()));
}
Marshal.ReleaseComObject(cutLine);
return(result.Count == 0 ? null : result);
}