Class OffsetCurveBuilder


  • public class OffsetCurveBuilder
    extends java.lang.Object
    Computes the raw offset curve for a single Geometry component (ring, line or point). A raw offset curve line is not noded - it may contain self-intersections (and usually will). The final buffer polygon is computed by forming a topological graph of all the noded raw curves and tracing outside contours. The points in the raw curve are rounded to a given PrecisionModel.
    Version:
    1.7
    • Method Detail

      • getBufferParameters

        public BufferParameters getBufferParameters()
        Gets the buffer parameters being used to generate the curve.
        Returns:
        the buffer parameters being used
      • getLineCurve

        public Coordinate[] getLineCurve​(Coordinate[] inputPts,
                                         double distance)
        This method handles single points as well as LineStrings. LineStrings are assumed not to be closed (the function will not fail for closed lines, but will generate superfluous line caps).
        Parameters:
        inputPts - the vertices of the line to offset
        distance - the offset distance
        Returns:
        a Coordinate array representing the curve or null if the curve is empty
      • isLineOffsetEmpty

        public boolean isLineOffsetEmpty​(double distance)
        Tests whether the offset curve for line or point geometries at the given offset distance is empty (does not exist). This is the case if:
        • the distance is zero,
        • the distance is negative, except for the case of singled-sided buffers
        Parameters:
        distance - the offset curve distance
        Returns:
        true if the offset curve is empty
      • getRingCurve

        public Coordinate[] getRingCurve​(Coordinate[] inputPts,
                                         int side,
                                         double distance)
        This method handles the degenerate cases of single points and lines, as well as valid rings.
        Parameters:
        inputPts - the coordinates of the ring (must not contain repeated points)
        side - side the side Position of the ring on which to construct the buffer line
        distance - the positive distance at which to create the offset
        Returns:
        a Coordinate array representing the curve, or null if the curve is empty