001 // License: GPL. See LICENSE file for details.
002 package org.openstreetmap.josm.data.validation.util;
003
004 import java.awt.geom.Point2D;
005 import java.util.ArrayList;
006 import java.util.Collections;
007 import java.util.HashSet;
008 import java.util.List;
009 import java.util.Map;
010 import java.util.Set;
011
012 import org.openstreetmap.josm.data.osm.Node;
013 import org.openstreetmap.josm.data.osm.Way;
014 import org.openstreetmap.josm.data.validation.OsmValidator;
015
016 /**
017 * Utility class
018 *
019 * @author frsantos
020 */
021 public class ValUtil
022 {
023 /**
024 * Returns the start and end cells of a way.
025 * @param w The way
026 * @param cellWays The map with all cells
027 * @return A list with all the cells the way starts or ends
028 */
029 public static List<List<Way>> getWaysInCell(Way w, Map<Point2D,List<Way>> cellWays) {
030 if (w.getNodesCount() == 0)
031 return Collections.emptyList();
032
033 Node n1 = w.getNode(0);
034 Node n2 = w.getNode(w.getNodesCount() - 1);
035
036 List<List<Way>> cells = new ArrayList<List<Way>>(2);
037 Set<Point2D> cellNodes = new HashSet<Point2D>();
038 Point2D cell;
039
040 // First, round coordinates
041 long x0 = Math.round(n1.getEastNorth().east() * OsmValidator.griddetail);
042 long y0 = Math.round(n1.getEastNorth().north() * OsmValidator.griddetail);
043 long x1 = Math.round(n2.getEastNorth().east() * OsmValidator.griddetail);
044 long y1 = Math.round(n2.getEastNorth().north() * OsmValidator.griddetail);
045
046 // Start of the way
047 cell = new Point2D.Double(x0, y0);
048 cellNodes.add(cell);
049 List<Way> ways = cellWays.get(cell);
050 if (ways == null) {
051 ways = new ArrayList<Way>();
052 cellWays.put(cell, ways);
053 }
054 cells.add(ways);
055
056 // End of the way
057 cell = new Point2D.Double(x1, y1);
058 if (!cellNodes.contains(cell)) {
059 cellNodes.add(cell);
060 ways = cellWays.get( cell );
061 if (ways == null) {
062 ways = new ArrayList<Way>();
063 cellWays.put(cell, ways);
064 }
065 cells.add(ways);
066 }
067
068 // Then floor coordinates, in case the way is in the border of the cell.
069 x0 = (long) Math.floor(n1.getEastNorth().east() * OsmValidator.griddetail);
070 y0 = (long) Math.floor(n1.getEastNorth().north() * OsmValidator.griddetail);
071 x1 = (long) Math.floor(n2.getEastNorth().east() * OsmValidator.griddetail);
072 y1 = (long) Math.floor(n2.getEastNorth().north() * OsmValidator.griddetail);
073
074 // Start of the way
075 cell = new Point2D.Double(x0, y0);
076 if (!cellNodes.contains(cell)) {
077 cellNodes.add(cell);
078 ways = cellWays.get(cell);
079 if (ways == null) {
080 ways = new ArrayList<Way>();
081 cellWays.put(cell, ways);
082 }
083 cells.add(ways);
084 }
085
086 // End of the way
087 cell = new Point2D.Double(x1, y1);
088 if (!cellNodes.contains(cell)) {
089 cellNodes.add(cell);
090 ways = cellWays.get(cell);
091 if (ways == null) {
092 ways = new ArrayList<Way>();
093 cellWays.put(cell, ways);
094 }
095 cells.add(ways);
096 }
097 return cells;
098 }
099
100 /**
101 * Returns the coordinates of all cells in a grid that a line between 2
102 * nodes intersects with.
103 *
104 * @param n1 The first node.
105 * @param n2 The second node.
106 * @param gridDetail The detail of the grid. Bigger values give smaller
107 * cells, but a bigger number of them.
108 * @return A list with the coordinates of all cells
109 */
110 public static List<Point2D> getSegmentCells(Node n1, Node n2, double gridDetail) {
111 List<Point2D> cells = new ArrayList<Point2D>();
112 double x0 = n1.getEastNorth().east() * gridDetail;
113 double x1 = n2.getEastNorth().east() * gridDetail;
114 double y0 = n1.getEastNorth().north() * gridDetail + 1;
115 double y1 = n2.getEastNorth().north() * gridDetail + 1;
116
117 if (x0 > x1) {
118 // Move to 1st-4th cuadrants
119 double aux;
120 aux = x0; x0 = x1; x1 = aux;
121 aux = y0; y0 = y1; y1 = aux;
122 }
123
124 double dx = x1 - x0;
125 double dy = y1 - y0;
126 long stepY = y0 <= y1 ? 1 : -1;
127 long gridX0 = (long) Math.floor(x0);
128 long gridX1 = (long) Math.floor(x1);
129 long gridY0 = (long) Math.floor(y0);
130 long gridY1 = (long) Math.floor(y1);
131
132 long maxSteps = (gridX1 - gridX0) + Math.abs(gridY1 - gridY0) + 1;
133 while ((gridX0 <= gridX1 && (gridY0 - gridY1)*stepY <= 0) && maxSteps-- > 0) {
134 cells.add( new Point2D.Double(gridX0, gridY0));
135
136 // Is the cross between the segment and next vertical line nearer than the cross with next horizontal line?
137 // Note: segment line formula: y=dy/dx(x-x1)+y1
138 // Note: if dy < 0, must use *bottom* line. If dy > 0, must use upper line
139 double scanY = dy/dx * (gridX0 + 1 - x1) + y1 + (dy < 0 ? -1 : 0);
140 double scanX = dx/dy * (gridY0 + (dy < 0 ? 0 : 1)*stepY - y1) + x1;
141
142 double distX = Math.pow(gridX0 + 1 - x0, 2) + Math.pow(scanY - y0, 2);
143 double distY = Math.pow(scanX - x0, 2) + Math.pow(gridY0 + stepY - y0, 2);
144
145 if (distX < distY) {
146 gridX0 += 1;
147 } else {
148 gridY0 += stepY;
149 }
150 }
151 return cells;
152 }
153 }