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    1   /*
    2    * Licensed to the Apache Software Foundation (ASF) under one or more
    3    * contributor license agreements.  See the NOTICE file distributed with
    4    * this work for additional information regarding copyright ownership.
    5    * The ASF licenses this file to You under the Apache License, Version 2.0
    6    * (the "License"); you may not use this file except in compliance with
    7    * the License.  You may obtain a copy of the License at
    8    *
    9    *      http://www.apache.org/licenses/LICENSE-2.0
    10   *
    11   * Unless required by applicable law or agreed to in writing, software
    12   * distributed under the License is distributed on an "AS IS" BASIS,
    13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    14   * See the License for the specific language governing permissions and
    15   * limitations under the License.
    16   */
    17  package org.apache.commons.geometry.examples.tutorials.bsp;
    18
    19  import java.io.File;
    20  import java.util.Arrays;
    21
    22  import org.apache.commons.geometry.euclidean.twod.Bounds2D;
    23  import org.apache.commons.geometry.euclidean.twod.RegionBSPTree2D;
    24  import org.apache.commons.geometry.euclidean.twod.Vector2D;
    25  import org.apache.commons.geometry.euclidean.twod.path.LinePath;
    26  import org.apache.commons.numbers.core.Precision;
    27
    28  /** Class containing tutorial code for constructing a balanced tree using a
    29   * partitioned region builder.
    30   */
    31  public final class HexagonPartitionedRegion {
    32
    33      /** No instantiation. */
    34      private HexagonPartitionedRegion() {}
    35
    36      /** Tutorial code entry point.
    37       * @param args command arguments; if given, the first argument is used as the location of
    38       *      output folder
    39       */
    40      public static void main(final String[] args) {
    41          final File outputFolder = new File(args.length > 0 ? args[0] : ".");
    42          final BSPTreeSVGWriter svgWriter = new BSPTreeSVGWriter(Bounds2D.from(Vector2D.of(-8, -8), Vector2D.of(8, 8)));
    43
    44          final Precision.DoubleEquivalence precision = Precision.doubleEquivalenceOfEpsilon(1e-6);
    45
    46          final LinePath path = LinePath.fromVertexLoop(Arrays.asList(
    47                  Vector2D.of(-4, 0),
    48                  Vector2D.of(-2, -3),
    49                  Vector2D.of(2, -3),
    50                  Vector2D.of(4, 0),
    51                  Vector2D.of(2, 3),
    52                  Vector2D.of(-2, 3)
    53              ), precision);
    54
    55          final RegionBSPTree2D tree = RegionBSPTree2D.partitionedRegionBuilder()
    56                  .insertAxisAlignedGrid(path.getBounds(), 1, precision)
    57                  .insertBoundaries(path)
    58                  .build();
    59
    60          svgWriter.write(tree, new File(outputFolder, "hex-partitioned.svg"));
    61      }
    62  }