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Diffstat (limited to 'src/main/java/org/apache/commons/math3/geometry/euclidean/threed/SubLine.java')
| -rw-r--r-- | src/main/java/org/apache/commons/math3/geometry/euclidean/threed/SubLine.java | 165 |
1 files changed, 165 insertions, 0 deletions
diff --git a/src/main/java/org/apache/commons/math3/geometry/euclidean/threed/SubLine.java b/src/main/java/org/apache/commons/math3/geometry/euclidean/threed/SubLine.java new file mode 100644 index 0000000..2ac917f --- /dev/null +++ b/src/main/java/org/apache/commons/math3/geometry/euclidean/threed/SubLine.java @@ -0,0 +1,165 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF licenses this file to You under the Apache License, Version 2.0 + * (the "License"); you may not use this file except in compliance with + * the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ +package org.apache.commons.math3.geometry.euclidean.threed; + +import java.util.ArrayList; +import java.util.List; + +import org.apache.commons.math3.exception.MathIllegalArgumentException; +import org.apache.commons.math3.geometry.Point; +import org.apache.commons.math3.geometry.euclidean.oned.Euclidean1D; +import org.apache.commons.math3.geometry.euclidean.oned.Interval; +import org.apache.commons.math3.geometry.euclidean.oned.IntervalsSet; +import org.apache.commons.math3.geometry.euclidean.oned.Vector1D; +import org.apache.commons.math3.geometry.partitioning.Region.Location; + +/** This class represents a subset of a {@link Line}. + * @since 3.0 + */ +public class SubLine { + + /** Default value for tolerance. */ + private static final double DEFAULT_TOLERANCE = 1.0e-10; + + /** Underlying line. */ + private final Line line; + + /** Remaining region of the hyperplane. */ + private final IntervalsSet remainingRegion; + + /** Simple constructor. + * @param line underlying line + * @param remainingRegion remaining region of the line + */ + public SubLine(final Line line, final IntervalsSet remainingRegion) { + this.line = line; + this.remainingRegion = remainingRegion; + } + + /** Create a sub-line from two endpoints. + * @param start start point + * @param end end point + * @param tolerance tolerance below which points are considered identical + * @exception MathIllegalArgumentException if the points are equal + * @since 3.3 + */ + public SubLine(final Vector3D start, final Vector3D end, final double tolerance) + throws MathIllegalArgumentException { + this(new Line(start, end, tolerance), buildIntervalSet(start, end, tolerance)); + } + + /** Create a sub-line from two endpoints. + * @param start start point + * @param end end point + * @exception MathIllegalArgumentException if the points are equal + * @deprecated as of 3.3, replaced with {@link #SubLine(Vector3D, Vector3D, double)} + */ + public SubLine(final Vector3D start, final Vector3D end) + throws MathIllegalArgumentException { + this(start, end, DEFAULT_TOLERANCE); + } + + /** Create a sub-line from a segment. + * @param segment single segment forming the sub-line + * @exception MathIllegalArgumentException if the segment endpoints are equal + */ + public SubLine(final Segment segment) throws MathIllegalArgumentException { + this(segment.getLine(), + buildIntervalSet(segment.getStart(), segment.getEnd(), segment.getLine().getTolerance())); + } + + /** Get the endpoints of the sub-line. + * <p> + * A subline may be any arbitrary number of disjoints segments, so the endpoints + * are provided as a list of endpoint pairs. Each element of the list represents + * one segment, and each segment contains a start point at index 0 and an end point + * at index 1. If the sub-line is unbounded in the negative infinity direction, + * the start point of the first segment will have infinite coordinates. If the + * sub-line is unbounded in the positive infinity direction, the end point of the + * last segment will have infinite coordinates. So a sub-line covering the whole + * line will contain just one row and both elements of this row will have infinite + * coordinates. If the sub-line is empty, the returned list will contain 0 segments. + * </p> + * @return list of segments endpoints + */ + public List<Segment> getSegments() { + + final List<Interval> list = remainingRegion.asList(); + final List<Segment> segments = new ArrayList<Segment>(list.size()); + + for (final Interval interval : list) { + final Vector3D start = line.toSpace((Point<Euclidean1D>) new Vector1D(interval.getInf())); + final Vector3D end = line.toSpace((Point<Euclidean1D>) new Vector1D(interval.getSup())); + segments.add(new Segment(start, end, line)); + } + + return segments; + + } + + /** Get the intersection of the instance and another sub-line. + * <p> + * This method is related to the {@link Line#intersection(Line) + * intersection} method in the {@link Line Line} class, but in addition + * to compute the point along infinite lines, it also checks the point + * lies on both sub-line ranges. + * </p> + * @param subLine other sub-line which may intersect instance + * @param includeEndPoints if true, endpoints are considered to belong to + * instance (i.e. they are closed sets) and may be returned, otherwise endpoints + * are considered to not belong to instance (i.e. they are open sets) and intersection + * occurring on endpoints lead to null being returned + * @return the intersection point if there is one, null if the sub-lines don't intersect + */ + public Vector3D intersection(final SubLine subLine, final boolean includeEndPoints) { + + // compute the intersection on infinite line + Vector3D v1D = line.intersection(subLine.line); + if (v1D == null) { + return null; + } + + // check location of point with respect to first sub-line + Location loc1 = remainingRegion.checkPoint((Point<Euclidean1D>) line.toSubSpace((Point<Euclidean3D>) v1D)); + + // check location of point with respect to second sub-line + Location loc2 = subLine.remainingRegion.checkPoint((Point<Euclidean1D>) subLine.line.toSubSpace((Point<Euclidean3D>) v1D)); + + if (includeEndPoints) { + return ((loc1 != Location.OUTSIDE) && (loc2 != Location.OUTSIDE)) ? v1D : null; + } else { + return ((loc1 == Location.INSIDE) && (loc2 == Location.INSIDE)) ? v1D : null; + } + + } + + /** Build an interval set from two points. + * @param start start point + * @param end end point + * @return an interval set + * @param tolerance tolerance below which points are considered identical + * @exception MathIllegalArgumentException if the points are equal + */ + private static IntervalsSet buildIntervalSet(final Vector3D start, final Vector3D end, final double tolerance) + throws MathIllegalArgumentException { + final Line line = new Line(start, end, tolerance); + return new IntervalsSet(line.toSubSpace((Point<Euclidean3D>) start).getX(), + line.toSubSpace((Point<Euclidean3D>) end).getX(), + tolerance); + } + +} |