| /* |
| * 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.geometry.hull; |
| |
| import java.util.Arrays; |
| import java.util.List; |
| |
| import org.apache.commons.geometry.core.precision.DoublePrecisionContext; |
| import org.apache.commons.geometry.core.precision.EpsilonDoublePrecisionContext; |
| import org.apache.commons.geometry.euclidean.EuclideanTestUtils; |
| import org.apache.commons.geometry.euclidean.twod.ConvexArea; |
| import org.apache.commons.geometry.euclidean.twod.Vector2D; |
| import org.apache.commons.geometry.hull.euclidean.twod.ConvexHull2D; |
| import org.apache.commons.geometry.hull.euclidean.twod.MonotoneChain; |
| import org.junit.Assert; |
| import org.junit.Test; |
| |
| /** This class contains code listed as examples in the user guide and other documentation. |
| * If any portion of this code changes, the corresponding examples in the documentation <em>must</em> be updated. |
| */ |
| public class DocumentationExamplesTest { |
| |
| private static final double TEST_EPS = 1e-15; |
| |
| @Test |
| public void testMonotoneChainExample() { |
| final DoublePrecisionContext precision = new EpsilonDoublePrecisionContext(1e-10); |
| |
| // create a list of input points for the algorithm |
| final List<Vector2D> pts = Arrays.asList( |
| Vector2D.ZERO, |
| Vector2D.of(0.5, 0.5), |
| Vector2D.of(0, 0.5), |
| Vector2D.of(0, 1), |
| Vector2D.of(0.25, 0.1), |
| Vector2D.of(1, 0), |
| Vector2D.of(1, 1), |
| Vector2D.of(0.75, 0.9) |
| ); |
| |
| // create an instance of the monotone chain convex hull generator |
| final MonotoneChain mc = new MonotoneChain(precision); |
| |
| // compute the convex hull |
| final ConvexHull2D hull = mc.generate(pts); |
| |
| // list the vertices from the input that were used in the hull |
| final List<Vector2D> vertices = hull.getVertices(); // [(0.0, 0.0), (1.0, 0.0), (1.0, 1.0), (0.0, 1.0)] |
| |
| // get the hull as a region |
| final ConvexArea region = hull.getRegion(); |
| final boolean containsAll = pts.stream().allMatch(region::contains); // true - region contains all input points |
| |
| // --- |
| Assert.assertEquals(4, vertices.size()); |
| EuclideanTestUtils.assertCoordinatesEqual(Vector2D.ZERO, vertices.get(0), TEST_EPS); |
| EuclideanTestUtils.assertCoordinatesEqual(Vector2D.of(1, 0), vertices.get(1), TEST_EPS); |
| EuclideanTestUtils.assertCoordinatesEqual(Vector2D.of(1, 1), vertices.get(2), TEST_EPS); |
| EuclideanTestUtils.assertCoordinatesEqual(Vector2D.of(0, 1), vertices.get(3), TEST_EPS); |
| |
| Assert.assertTrue(containsAll); |
| } |
| } |