Class OffsetCurveSetBuilder
java.lang.Object
org.locationtech.jts.operation.buffer.OffsetCurveSetBuilder
Creates all the raw offset curves for a buffer of a
Geometry
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Raw curves need to be noded together and polygonized to form the final buffer area.- Version:
- 1.7
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Field Summary
FieldsModifier and TypeFieldDescriptionprivate OffsetCurveBuilder
private List
private double
private Geometry
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Constructor Summary
ConstructorsConstructorDescriptionOffsetCurveSetBuilder
(Geometry inputGeom, double distance, OffsetCurveBuilder curveBuilder) -
Method Summary
Modifier and TypeMethodDescriptionprivate void
private void
private void
addCurve
(Coordinate[] coord, int leftLoc, int rightLoc) Creates aSegmentString
for a coordinate list which is a raw offset curve, and adds it to the list of buffer curves.private void
addLineString
(LineString line) private void
Add a Point to the graph.private void
private void
addPolygonRing
(Coordinate[] coord, double offsetDistance, int side, int cwLeftLoc, int cwRightLoc) Adds an offset curve for a polygon ring.Computes the set of raw offset curves for the buffer.private boolean
isErodedCompletely
(LinearRing ring, double bufferDistance) The ringCoord is assumed to contain no repeated points.private boolean
isTriangleErodedCompletely
(Coordinate[] triangleCoord, double bufferDistance) Tests whether a triangular ring would be eroded completely by the given buffer distance.
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Field Details
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inputGeom
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distance
private double distance -
curveBuilder
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curveList
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Constructor Details
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OffsetCurveSetBuilder
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Method Details
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getCurves
Computes the set of raw offset curves for the buffer. Each offset curve has an attachedLabel
indicating its left and right location.- Returns:
- a Collection of SegmentStrings representing the raw buffer curves
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addCurve
Creates aSegmentString
for a coordinate list which is a raw offset curve, and adds it to the list of buffer curves. The SegmentString is tagged with a Label giving the topology of the curve. The curve may be oriented in either direction. If the curve is oriented CW, the locations will be:
Left: Location.EXTERIOR
Right: Location.INTERIOR -
add
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addCollection
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addPoint
Add a Point to the graph. -
addLineString
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addPolygon
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addPolygonRing
private void addPolygonRing(Coordinate[] coord, double offsetDistance, int side, int cwLeftLoc, int cwRightLoc) Adds an offset curve for a polygon ring. The side and left and right topological location arguments assume that the ring is oriented CW. If the ring is in the opposite orientation, the left and right locations must be interchanged and the side flipped.- Parameters:
coord
- the coordinates of the ring (must not contain repeated points)offsetDistance
- the distance at which to create the bufferside
- the side of the ring on which to construct the buffer linecwLeftLoc
- the location on the L side of the ring (if it is CW)cwRightLoc
- the location on the R side of the ring (if it is CW)
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isErodedCompletely
The ringCoord is assumed to contain no repeated points. It may be degenerate (i.e. contain only 1, 2, or 3 points). In this case it has no area, and hence has a minimum diameter of 0.- Parameters:
ringCoord
-offsetDistance
-- Returns:
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isTriangleErodedCompletely
Tests whether a triangular ring would be eroded completely by the given buffer distance. This is a precise test. It uses the fact that the inner buffer of a triangle converges on the inCentre of the triangle (the point equidistant from all sides). If the buffer distance is greater than the distance of the inCentre from a side, the triangle will be eroded completely. This test is important, since it removes a problematic case where the buffer distance is slightly larger than the inCentre distance. In this case the triangle buffer curve "inverts" with incorrect topology, producing an incorrect hole in the buffer.- Parameters:
triangleCoord
-bufferDistance
-- Returns:
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