1 | // License: GPL. For details, see LICENSE file.
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2 | package org.openstreetmap.josm.data.imagery.vectortile.mapbox;
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3 |
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4 | import static org.openstreetmap.josm.tools.I18n.tr;
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5 |
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6 | import java.awt.Shape;
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7 | import java.awt.geom.Area;
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8 | import java.awt.geom.Ellipse2D;
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9 | import java.awt.geom.Path2D;
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10 | import java.util.ArrayList;
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11 | import java.util.Collection;
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12 | import java.util.Collections;
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13 | import java.util.List;
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14 |
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15 | /**
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16 | * A class to generate geometry for a vector tile
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17 | * @author Taylor Smock
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18 | * @since xxx
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19 | */
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20 | public class Geometry {
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21 | final Collection<Shape> shapes = new ArrayList<>();
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22 |
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23 | /**
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24 | * Create a {@link Geometry} for a {@link Feature}
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25 | * @param geometryType The type of geometry
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26 | * @param commands The commands used to create the geometry
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27 | */
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28 | public Geometry(GeometryTypes geometryType, List<CommandInteger> commands) {
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29 | if (geometryType == GeometryTypes.POINT) {
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30 | for (CommandInteger command : commands) {
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31 | final short[] operations = command.getOperations();
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32 | // Each MoveTo command is a new point
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33 | if (command.getType() == Command.MoveTo && operations.length % 2 == 0 && operations.length > 0) {
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34 | for (int i = 0; i < operations.length / 2; i++) {
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35 | // Just using Ellipse2D since it extends Shape
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36 | shapes.add(new Ellipse2D.Float(operations[2 * i],
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37 | operations[2 * i + 1], 0, 0));
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38 | }
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39 | } else {
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40 | throw new IllegalArgumentException(tr("{0} with {1} arguments is not understood", geometryType, operations.length));
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41 | }
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42 | }
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43 | } else if (geometryType == GeometryTypes.LINESTRING || geometryType == GeometryTypes.POLYGON) {
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44 | Path2D.Float line = null;
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45 | Area area = null;
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46 | // MVT uses delta encoding. Each feature starts at (0, 0).
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47 | double x = 0;
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48 | double y = 0;
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49 | // Area is used to determine the inner/outer of a polygon
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50 | double areaAreaSq = 0;
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51 | for (CommandInteger command : commands) {
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52 | final short[] operations = command.getOperations();
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53 | // Technically, there is no reason why there can be multiple MoveTo operations in one command, but that is undefined behavior
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54 | if (command.getType() == Command.MoveTo && operations.length == 2) {
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55 | areaAreaSq = 0;
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56 | x += operations[0];
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57 | y += operations[1];
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58 | line = new Path2D.Float();
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59 | line.moveTo(x, y);
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60 | shapes.add(line);
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61 | } else if (command.getType() == Command.LineTo && operations.length % 2 == 0 && line != null) {
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62 | for (int i = 0; i < operations.length / 2; i++) {
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63 | final double lx = x;
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64 | final double ly = y;
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65 | x += operations[2 * i];
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66 | y += operations[2 * i + 1];
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67 | areaAreaSq += lx * y - x * ly;
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68 | line.lineTo(x, y);
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69 | }
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70 | // ClosePath should only be used with Polygon geometry
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71 | } else if (geometryType == GeometryTypes.POLYGON && command.getType() == Command.ClosePath && line != null) {
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72 | shapes.remove(line);
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73 | // new Area() closes the line if it isn't already closed
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74 | if (area == null) {
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75 | area = new Area();
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76 | shapes.add(area);
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77 | }
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78 |
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79 | Area nArea = new Area(line);
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80 | // SonarLint thinks that this is never > 0. It can be.
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81 | if (areaAreaSq > 0) {
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82 | area.add(nArea);
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83 | } else if (areaAreaSq < 0) {
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84 | area.exclusiveOr(nArea);
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85 | } else {
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86 | throw new IllegalArgumentException(tr("{0} cannot have zero area", geometryType));
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87 | }
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88 | } else {
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89 | throw new IllegalArgumentException(tr("{0} with {1} arguments is not understood", geometryType, operations.length));
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90 | }
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91 | }
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92 | }
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93 | }
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94 |
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95 | /**
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96 | * Get the shapes to draw this geometry with
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97 | * @return A collection of shapes
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98 | */
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99 | public Collection<Shape> getShapes() {
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100 | return Collections.unmodifiableCollection(this.shapes);
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101 | }
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102 | }
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