VariableBufferTest.java

/*
 * Copyright (c) 2019 Martin Davis.
 *
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * and Eclipse Distribution License v. 1.0 which accompanies this distribution.
 * The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v20.html
 * and the Eclipse Distribution License is available at
 *
 * http://www.eclipse.org/org/documents/edl-v10.php.
 */
package org.locationtech.jts.operation.buffer;

import org.locationtech.jts.geom.Geometry;

import test.jts.GeometryTestCase;

public class VariableBufferTest extends GeometryTestCase {

  //-- low tolerance reduces expected geometry literal size
  private static final double DEFAULT_TOLERANCE = 1.0e-2;

  public VariableBufferTest(String name) {
    super(name);
  }

  public static void main(String[] args) {
    junit.textui.TestRunner.run(VariableBufferTest.class);
  }
  
  public void testZeroWidth() {
    checkBuffer("LINESTRING( 0 0, 6 6, 10 10)",
        0, 0,
        "POLYGON EMPTY");
  }

  public void testZeroLength() {
    checkBuffer("LINESTRING( 10 10, 10 10 )",
        0, 0,
        "POLYGON EMPTY");
  }

  public void testSegmentInverseDist() {
    checkBuffer("LINESTRING (100 100, 200 100)",
        10, 1,
        "POLYGON ((100 90, 98.05 90.19, 96.17 90.76, 94.44 91.69, 92.93 92.93, 91.69 94.44, 90.76 96.17, 90.19 98.05, 90 100, 90.19 101.95, 90.76 103.83, 91.69 105.56, 92.93 107.07, 94.44 108.31, 96.17 109.24, 98.05 109.81, 100 110, 100.9 109.96, 200.09 101, 200.2 100.98, 200.38 100.92, 200.56 100.83, 200.71 100.71, 200.83 100.56, 200.92 100.38, 200.98 100.2, 201 100, 200.98 99.8, 200.92 99.62, 200.83 99.44, 200.71 99.29, 200.56 99.17, 200.38 99.08, 200.2 99.02, 200.09 99, 100.9 90.04, 100 90))"
        );
  }

  public void testSegmentSameDist() {
    checkBuffer("LINESTRING (100 100, 200 100)",
        10, 10,
        "POLYGON ((201.95 109.81, 203.83 109.24, 205.56 108.31, 207.07 107.07, 208.31 105.56, 209.24 103.83, 209.81 101.95, 210 100, 209.81 98.05, 209.24 96.17, 208.31 94.44, 207.07 92.93, 205.56 91.69, 203.83 90.76, 201.95 90.19, 200 90, 100 90, 98.05 90.19, 96.17 90.76, 94.44 91.69, 92.93 92.93, 91.69 94.44, 90.76 96.17, 90.19 98.05, 90 100, 90.19 101.95, 90.76 103.83, 91.69 105.56, 92.93 107.07, 94.44 108.31, 96.17 109.24, 98.05 109.81, 100 110, 200 110, 201.95 109.81))"
        );
  }

  public void testOneSegment() {
    checkBuffer("LINESTRING (100 100, 200 100)",
        10, 30,
"POLYGON ((200 130, 205.85 129.42, 211.48 127.72, 216.67 124.94, 221.21 121.21, 224.94 116.67, 227.72 111.48, 229.42 105.85, 230 100, 229.42 94.15, 227.72 88.52, 224.94 83.33, 221.21 78.79, 216.67 75.06, 211.48 72.28, 205.85 70.58, 200 70, 194 70.61, 98 90.2, 96.17 90.76, 94.44 91.69, 92.93 92.93, 91.69 94.44, 90.76 96.17, 90.19 98.05, 90 100, 90.19 101.95, 90.76 103.83, 91.69 105.56, 92.93 107.07, 94.44 108.31, 96.17 109.24, 98 109.8, 194 129.39, 200 130))"
        );
  }

  public void testSegments2() {
    checkBuffer("LINESTRING( 0 0, 40 40, 60 -20)",
        10, 20,
        "POLYGON ((79.62 -16.1, 80 -20, 79.62 -23.9, 78.48 -27.65, 76.63 -31.11, 74.14 -34.14, 71.11 -36.63, 67.65 -38.48, 63.9 -39.62, 60 -40, 56.1 -39.62, 52.35 -38.48, 48.89 -36.63, 45.86 -34.14, 43.37 -31.11, 41.52 -27.65, 40.56 -24.72, 31.31 13.38, 6.46 -7.64, 5.56 -8.31, 3.83 -9.24, 1.95 -9.81, 0 -10, -1.95 -9.81, -3.83 -9.24, -5.56 -8.31, -7.07 -7.07, -8.31 -5.56, -9.24 -3.83, -9.81 -1.95, -10 0, -9.81 1.95, -9.24 3.83, -8.31 5.56, -7.64 6.46, 28.76 49.5, 29.59 50.41, 31.82 52.24, 34.37 53.6, 37.13 54.44, 40 54.72, 42.87 54.44, 45.63 53.6, 48.18 52.24, 50.41 50.41, 52.24 48.18, 53.53 45.8, 78.38 -12.11, 79.62 -16.1))"
        );
  }

  public void testLargeDistance() {
    checkBuffer("LINESTRING( 0 0, 10 10)",
        1, 200,
        "POLYGON ((206.16 -29.02, 194.78 -66.54, 176.29 -101.11, 151.42 -131.42, 121.11 -156.29, 86.54 -174.78, 49.02 -186.16, 10 -190, -29.02 -186.16, -66.54 -174.78, -101.11 -156.29, -131.42 -131.42, -156.29 -101.11, -174.78 -66.54, -186.16 -29.02, -190 10, -186.16 49.02, -174.78 86.54, -156.29 121.11, -131.42 151.42, -101.11 176.29, -66.54 194.78, -29.02 206.16, 10 210, 49.02 206.16, 86.54 194.78, 121.11 176.29, 151.42 151.42, 176.29 121.11, 194.78 86.54, 206.16 49.02, 210 10, 206.16 -29.02))"
        );
  }

  public void testZeroDistanceAtVertex() {
    checkBuffer("LINESTRING( 10 10, 20 20, 30 30)",
        new double[] { 5, 0, 5 },
        "MULTIPOLYGON (((5.1 10.98, 5.38 11.91, 5.84 12.78, 6.46 13.54, 7.22 14.16, 7.94 14.56, 20 20, 14.56 7.94, 14.16 7.22, 13.54 6.46, 12.78 5.84, 11.91 5.38, 10.98 5.1, 10 5, 9.02 5.1, 8.09 5.38, 7.22 5.84, 6.46 6.46, 5.84 7.22, 5.38 8.09, 5.1 9.02, 5 10, 5.1 10.98)), ((25.44 32.06, 25.84 32.78, 26.46 33.54, 27.22 34.16, 28.09 34.62, 29.02 34.9, 30 35, 30.98 34.9, 31.91 34.62, 32.78 34.16, 33.54 33.54, 34.16 32.78, 34.62 31.91, 34.9 30.98, 35 30, 34.9 29.02, 34.62 28.09, 34.16 27.22, 33.54 26.46, 32.78 25.84, 32.06 25.44, 20 20, 25.44 32.06)))"
        );
  }
  
  public void testZeroDistancesForSegment() {
    checkBuffer("LINESTRING( 10 10, 20 20, 30 30, 40 40)",
        new double[] { 5, 0, 0, 5 },
        "MULTIPOLYGON (((5.1 10.98, 5.38 11.91, 5.84 12.78, 6.46 13.54, 7.22 14.16, 7.94 14.56, 20 20, 14.56 7.94, 14.16 7.22, 13.54 6.46, 12.78 5.84, 11.91 5.38, 10.98 5.1, 10 5, 9.02 5.1, 8.09 5.38, 7.22 5.84, 6.46 6.46, 5.84 7.22, 5.38 8.09, 5.1 9.02, 5 10, 5.1 10.98)), ((35.44 42.06, 35.84 42.78, 36.46 43.54, 37.22 44.16, 38.09 44.62, 39.02 44.9, 40 45, 40.98 44.9, 41.91 44.62, 42.78 44.16, 43.54 43.54, 44.16 42.78, 44.62 41.91, 44.9 40.98, 45 40, 44.9 39.02, 44.62 38.09, 44.16 37.22, 43.54 36.46, 42.78 35.84, 42.06 35.44, 30 30, 35.44 42.06)))"
        );
  }
  
  // see https://github.com/locationtech/jts/issues/998
  public void testIssue998_Spike() {
    checkBuffer("LINESTRING (0.024520295 69.50077743, 0.000508719 74.50086084, 0 76.39546845)",
        new double[] {  6.47, 6.9, 7 },
        "POLYGON ((-6.87 77.76, -6.47 79.07, -5.82 80.28, -4.95 81.35, -3.89 82.22, -2.68 82.86, -1.37 83.26, 0 83.4, 1.37 83.26, 2.68 82.86, 3.89 82.22, 4.95 81.35, 5.82 80.28, 6.47 79.07, 6.87 77.76, 7 76.4, 6.99 76.03, 6.89 74.14, 6.88 74.08, 6.88 73.94, 6.47 68.98, 6.37 68.24, 6 67.02, 5.4 65.91, 4.6 64.93, 3.62 64.12, 2.5 63.52, 1.29 63.16, 0.02 63.03, -1.24 63.16, -2.45 63.52, -3.57 64.12, -4.55 64.93, -5.36 65.91, -5.95 67.02, -6.32 68.24, -6.42 68.91, -6.87 73.87, -6.88 74.05, -6.89 74.13, -6.99 76.02, -7 76.4, -6.87 77.76))"
        );
  }
  
  public void testNoReverseSpike() {
    checkBuffer("LINESTRING (0 70, 0 80)",
        new double[] {  4, 7 },
        "POLYGON ((-6.87 78.63, -7 80, -6.87 81.37, -6.47 82.68, -5.82 83.89, -4.95 84.95, -3.89 85.82, -2.68 86.47, -1.37 86.87, 0 87, 1.37 86.87, 2.68 86.47, 3.89 85.82, 4.95 84.95, 5.82 83.89, 6.47 82.68, 6.87 81.37, 7 80, 6.87 78.63, 6.68 77.9, 3.82 68.8, 3.7 68.47, 3.33 67.78, 2.83 67.17, 2.22 66.67, 1.53 66.3, 0.78 66.08, 0 66, -0.78 66.08, -1.53 66.3, -2.22 66.67, -2.83 67.17, -3.33 67.78, -3.7 68.47, -3.82 68.8, -6.68 77.9, -6.87 78.63))"
        );
  }
  
  public void testNoShortCapSegments() {
    checkBuffer("LINESTRING (6.85 78.25, 18 87)",
        new double[] { 5, 9 },
        "POLYGON ((11.64 93.36, 13 94.48, 14.56 95.31, 16.24 95.83, 18 96, 19.76 95.83, 21.44 95.31, 23 94.48, 24.36 93.36, 25.48 92, 26.31 90.44, 26.83 88.76, 27 87, 26.83 85.24, 26.31 83.56, 25.48 82, 24.36 80.64, 23 79.52, 21.33 78.64, 8.7 73.61, 7.83 73.35, 6.85 73.25, 5.87 73.35, 4.94 73.63, 4.07 74.09, 3.31 74.71, 2.69 75.47, 2.23 76.34, 1.95 77.27, 1.85 78.25, 1.95 79.23, 2.23 80.16, 2.78 81.15, 10.67 92.22, 11.64 93.36))"
        );
  }
  
  //================================================================
  
  private void checkBuffer(String wkt, double startDist, double endDist, 
      String wktExpected) {
    Geometry geom = read(wkt);
    Geometry result = VariableBuffer.buffer(geom, startDist, endDist);
    //System.out.println(result);
    checkBuffer(result, wktExpected);
  }

  private void checkBuffer(String wkt, double[] dist, 
      String wktExpected) {
    Geometry geom = read(wkt);
    Geometry result = VariableBuffer.buffer(geom, dist);
    //System.out.println(result);
    checkBuffer(result, wktExpected);
  }

  private void checkBuffer(Geometry actual, String wktExpected) {
    Geometry expected = read(wktExpected);
    checkEqual(expected, actual, DEFAULT_TOLERANCE);
  }
}