001// License: GPL. See LICENSE file for details.
002package org.openstreetmap.josm.data.validation.util;
003
004import java.awt.geom.Point2D;
005import java.util.ArrayList;
006import java.util.Collections;
007import java.util.HashSet;
008import java.util.List;
009import java.util.Map;
010import java.util.Set;
011
012import org.openstreetmap.josm.data.coor.EastNorth;
013import org.openstreetmap.josm.data.osm.Node;
014import org.openstreetmap.josm.data.osm.Way;
015import org.openstreetmap.josm.data.validation.OsmValidator;
016import org.openstreetmap.josm.tools.CheckParameterUtil;
017
018/**
019 * Utility class
020 *
021 * @author frsantos
022 */
023public final class ValUtil {
024
025    private ValUtil() {
026        // Hide default constructor for utils classes
027    }
028
029    /**
030     * Returns the start and end cells of a way.
031     * @param w The way
032     * @param cellWays The map with all cells
033     * @return A list with all the cells the way starts or ends
034     */
035    public static List<List<Way>> getWaysInCell(Way w, Map<Point2D,List<Way>> cellWays) {
036        if (w.getNodesCount() == 0)
037            return Collections.emptyList();
038
039        Node n1 = w.getNode(0);
040        Node n2 = w.getNode(w.getNodesCount() - 1);
041
042        List<List<Way>> cells = new ArrayList<>(2);
043        Set<Point2D> cellNodes = new HashSet<>();
044        Point2D cell;
045
046        // First, round coordinates
047        long x0 = Math.round(n1.getEastNorth().east()  * OsmValidator.griddetail);
048        long y0 = Math.round(n1.getEastNorth().north() * OsmValidator.griddetail);
049        long x1 = Math.round(n2.getEastNorth().east()  * OsmValidator.griddetail);
050        long y1 = Math.round(n2.getEastNorth().north() * OsmValidator.griddetail);
051
052        // Start of the way
053        cell = new Point2D.Double(x0, y0);
054        cellNodes.add(cell);
055        List<Way> ways = cellWays.get(cell);
056        if (ways == null) {
057            ways = new ArrayList<>();
058            cellWays.put(cell, ways);
059        }
060        cells.add(ways);
061
062        // End of the way
063        cell = new Point2D.Double(x1, y1);
064        if (!cellNodes.contains(cell)) {
065            cellNodes.add(cell);
066            ways = cellWays.get( cell );
067            if (ways == null) {
068                ways = new ArrayList<>();
069                cellWays.put(cell, ways);
070            }
071            cells.add(ways);
072        }
073
074        // Then floor coordinates, in case the way is in the border of the cell.
075        x0 = (long) Math.floor(n1.getEastNorth().east()  * OsmValidator.griddetail);
076        y0 = (long) Math.floor(n1.getEastNorth().north() * OsmValidator.griddetail);
077        x1 = (long) Math.floor(n2.getEastNorth().east()  * OsmValidator.griddetail);
078        y1 = (long) Math.floor(n2.getEastNorth().north() * OsmValidator.griddetail);
079
080        // Start of the way
081        cell = new Point2D.Double(x0, y0);
082        if (!cellNodes.contains(cell)) {
083            cellNodes.add(cell);
084            ways = cellWays.get(cell);
085            if (ways == null) {
086                ways = new ArrayList<>();
087                cellWays.put(cell, ways);
088            }
089            cells.add(ways);
090        }
091
092        // End of the way
093        cell = new Point2D.Double(x1, y1);
094        if (!cellNodes.contains(cell)) {
095            cellNodes.add(cell);
096            ways = cellWays.get(cell);
097            if (ways == null) {
098                ways = new ArrayList<>();
099                cellWays.put(cell, ways);
100            }
101            cells.add(ways);
102        }
103        return cells;
104    }
105
106    /**
107     * Returns the coordinates of all cells in a grid that a line between 2 nodes intersects with.
108     *
109     * @param n1 The first node.
110     * @param n2 The second node.
111     * @param gridDetail The detail of the grid. Bigger values give smaller
112     * cells, but a bigger number of them.
113     * @return A list with the coordinates of all cells
114     * @throws IllegalArgumentException if n1 or n2 is {@code null} or without coordinates
115     */
116    public static List<Point2D> getSegmentCells(Node n1, Node n2, double gridDetail) throws IllegalArgumentException {
117        CheckParameterUtil.ensureParameterNotNull(n1, "n1");
118        CheckParameterUtil.ensureParameterNotNull(n1, "n2");
119        return getSegmentCells(n1.getEastNorth(), n2.getEastNorth(), gridDetail);
120    }
121
122    /**
123     * Returns the coordinates of all cells in a grid that a line between 2 nodes intersects with.
124     *
125     * @param en1 The first EastNorth.
126     * @param en2 The second EastNorth.
127     * @param gridDetail The detail of the grid. Bigger values give smaller
128     * cells, but a bigger number of them.
129     * @return A list with the coordinates of all cells
130     * @throws IllegalArgumentException if en1 or en2 is {@code null}
131     * @since 6869
132     */
133    public static List<Point2D> getSegmentCells(EastNorth en1, EastNorth en2, double gridDetail) throws IllegalArgumentException {
134        CheckParameterUtil.ensureParameterNotNull(en1, "en1");
135        CheckParameterUtil.ensureParameterNotNull(en2, "en2");
136        List<Point2D> cells = new ArrayList<>();
137        double x0 = en1.east() * gridDetail;
138        double x1 = en2.east() * gridDetail;
139        double y0 = en1.north() * gridDetail + 1;
140        double y1 = en2.north() * gridDetail + 1;
141
142        if (x0 > x1) {
143            // Move to 1st-4th cuadrants
144            double aux;
145            aux = x0; x0 = x1; x1 = aux;
146            aux = y0; y0 = y1; y1 = aux;
147        }
148
149        double dx  = x1 - x0;
150        double dy  = y1 - y0;
151        long stepY = y0 <= y1 ? 1 : -1;
152        long gridX0 = (long) Math.floor(x0);
153        long gridX1 = (long) Math.floor(x1);
154        long gridY0 = (long) Math.floor(y0);
155        long gridY1 = (long) Math.floor(y1);
156
157        long maxSteps = (gridX1 - gridX0) + Math.abs(gridY1 - gridY0) + 1;
158        while ((gridX0 <= gridX1 && (gridY0 - gridY1)*stepY <= 0) && maxSteps-- > 0) {
159            cells.add( new Point2D.Double(gridX0, gridY0));
160
161            // Is the cross between the segment and next vertical line nearer than the cross with next horizontal line?
162            // Note: segment line formula: y=dy/dx(x-x1)+y1
163            // Note: if dy < 0, must use *bottom* line. If dy > 0, must use upper line
164            double scanY = dy/dx * (gridX0 + 1 - x1) + y1 + (dy < 0 ? -1 : 0);
165            double scanX = dx/dy * (gridY0 + (dy < 0 ? 0 : 1)*stepY - y1) + x1;
166
167            double distX = Math.pow(gridX0 + 1 - x0, 2) + Math.pow(scanY - y0, 2);
168            double distY = Math.pow(scanX - x0, 2) + Math.pow(gridY0 + stepY - y0, 2);
169
170            if (distX < distY) {
171                gridX0 += 1;
172            } else {
173                gridY0 += stepY;
174            }
175        }
176        return cells;
177    }
178}