001// License: GPL. For details, see LICENSE file. 002package org.openstreetmap.josm.actions; 003 004import static org.openstreetmap.josm.tools.I18n.tr; 005 006import java.awt.event.ActionEvent; 007import java.awt.event.KeyEvent; 008import java.util.Arrays; 009import java.util.Collection; 010import java.util.List; 011import java.util.Set; 012 013import org.openstreetmap.josm.actions.mapmode.DrawAction; 014import org.openstreetmap.josm.command.ChangeCommand; 015import org.openstreetmap.josm.command.SelectCommand; 016import org.openstreetmap.josm.command.SequenceCommand; 017import org.openstreetmap.josm.data.UndoRedoHandler; 018import org.openstreetmap.josm.data.osm.DataSet; 019import org.openstreetmap.josm.data.osm.Node; 020import org.openstreetmap.josm.data.osm.OsmPrimitive; 021import org.openstreetmap.josm.data.osm.Way; 022import org.openstreetmap.josm.gui.MainApplication; 023import org.openstreetmap.josm.gui.MapFrame; 024import org.openstreetmap.josm.tools.Shortcut; 025import org.openstreetmap.josm.tools.Utils; 026 027/** 028 * Follow line action - Makes easier to draw a line that shares points with another line 029 * 030 * Aimed at those who want to draw two or more lines related with 031 * each other, but carry different information (i.e. a river acts as boundary at 032 * some part of its course. It preferable to have a separated boundary line than to 033 * mix totally different kind of features in one single way). 034 * 035 * @author Germán Márquez Mejía 036 */ 037public class FollowLineAction extends JosmAction { 038 039 /** 040 * Constructs a new {@code FollowLineAction}. 041 */ 042 public FollowLineAction() { 043 super( 044 tr("Follow line"), 045 "followline", 046 tr("Continues drawing a line that shares nodes with another line."), 047 Shortcut.registerShortcut("tools:followline", tr( 048 "Tool: {0}", tr("Follow")), 049 KeyEvent.VK_F, Shortcut.DIRECT), true); 050 } 051 052 @Override 053 protected void updateEnabledState() { 054 updateEnabledStateOnCurrentSelection(); 055 } 056 057 @Override 058 protected void updateEnabledState(Collection<? extends OsmPrimitive> selection) { 059 updateEnabledStateOnModifiableSelection(selection); 060 } 061 062 @Override 063 public void actionPerformed(ActionEvent evt) { 064 DataSet ds = getLayerManager().getEditDataSet(); 065 if (ds == null) 066 return; 067 MapFrame map = MainApplication.getMap(); 068 if (!(map.mapMode instanceof DrawAction)) return; // We are not on draw mode 069 070 Collection<Node> selectedPoints = ds.getSelectedNodes(); 071 Collection<Way> selectedLines = ds.getSelectedWays(); 072 if ((selectedPoints.size() > 1) || (selectedLines.size() != 1)) // Unsuitable selection 073 return; 074 075 Node last = ((DrawAction) map.mapMode).getCurrentBaseNode(); 076 if (last == null) 077 return; 078 Way follower = selectedLines.iterator().next(); 079 if (follower.isClosed()) /* Don't loop until OOM */ 080 return; 081 Node prev = follower.getNode(1); 082 boolean reversed = true; 083 if (follower.lastNode().equals(last)) { 084 prev = follower.getNode(follower.getNodesCount() - 2); 085 reversed = false; 086 } 087 List<OsmPrimitive> referrers = last.getReferrers(); 088 if (referrers.size() < 2) return; // There's nothing to follow 089 090 Node newPoint = null; 091 for (final Way toFollow : Utils.filteredCollection(referrers, Way.class)) { 092 if (toFollow.equals(follower)) { 093 continue; 094 } 095 Set<Node> points = toFollow.getNeighbours(last); 096 points.remove(prev); 097 if (points.isEmpty()) // No candidate -> consider next way 098 continue; 099 if (points.size() > 1) // Ambiguous junction? 100 return; 101 102 // points contains exactly one element 103 Node newPointCandidate = points.iterator().next(); 104 105 if ((newPoint != null) && (newPoint != newPointCandidate)) 106 return; // Ambiguous junction, force to select next 107 108 newPoint = newPointCandidate; 109 } 110 if (newPoint != null) { 111 Way newFollower = new Way(follower); 112 if (reversed) { 113 newFollower.addNode(0, newPoint); 114 } else { 115 newFollower.addNode(newPoint); 116 } 117 UndoRedoHandler.getInstance().add(new SequenceCommand(tr("Follow line"), 118 new ChangeCommand(ds, follower, newFollower), 119 new SelectCommand(ds, newFollower.isClosed() // see #10028 - unselect last node when closing a way 120 ? Arrays.<OsmPrimitive>asList(follower) 121 : Arrays.<OsmPrimitive>asList(follower, newPoint) 122 )) 123 ); 124 // "viewport following" mode for tracing long features 125 // from aerial imagery or GPS tracks. 126 if (DrawAction.VIEWPORT_FOLLOWING.get()) { 127 map.mapView.smoothScrollTo(newPoint.getEastNorth()); 128 } 129 } 130 } 131}