private static int GetLocalIntersectionSegmentIdx([NotNull] Linestring forSegments,
double virtualVertexIndex,
out double distanceAlongAsRatio)
{
Assert.ArgumentNotNull(forSegments, nameof(forSegments));
Assert.ArgumentNotNaN(virtualVertexIndex, nameof(virtualVertexIndex));
var localSegmentIdx = (int)Math.Truncate(virtualVertexIndex);
distanceAlongAsRatio = virtualVertexIndex - localSegmentIdx;
if (forSegments.IsLastPointInPart(localSegmentIdx) && distanceAlongAsRatio >= 0)
{
// out of segment bounds:
if (forSegments.IsClosed)
{
localSegmentIdx = 0;
}
else
{
// last segment, end point:
localSegmentIdx -= 1;
distanceAlongAsRatio += 1;
}
}
return(localSegmentIdx);
}
private static bool IsRingStartOrEnd([NotNull] Linestring linestring,
double localVertexIndex)
{
Assert.False(double.IsNaN(localVertexIndex), "localVertexIndex is NaN");
var vertexIndexIntegral = (int)localVertexIndex;
// ReSharper disable once CompareOfFloatsByEqualityOperator
bool isVertex = localVertexIndex == vertexIndexIntegral;
if (!isVertex)
{
return(false);
}
if (linestring.IsFirstPointInPart(vertexIndexIntegral) ||
linestring.IsLastPointInPart(vertexIndexIntegral))
{
return(linestring.IsClosed);
}
return(false);
}