001// License: GPL. For details, see LICENSE file.
002package org.openstreetmap.josm.actions;
003
004import static org.openstreetmap.josm.gui.help.HelpUtil.ht;
005import static org.openstreetmap.josm.tools.I18n.tr;
006import static org.openstreetmap.josm.tools.I18n.trn;
007
008import java.awt.event.ActionEvent;
009import java.awt.event.KeyEvent;
010import java.util.ArrayList;
011import java.util.Collection;
012import java.util.Collections;
013import java.util.HashSet;
014import java.util.LinkedList;
015import java.util.List;
016
017import javax.swing.JOptionPane;
018
019import org.openstreetmap.josm.Main;
020import org.openstreetmap.josm.command.ChangeCommand;
021import org.openstreetmap.josm.command.Command;
022import org.openstreetmap.josm.command.DeleteCommand;
023import org.openstreetmap.josm.command.SequenceCommand;
024import org.openstreetmap.josm.data.osm.DataSet;
025import org.openstreetmap.josm.data.osm.Node;
026import org.openstreetmap.josm.data.osm.OsmPrimitive;
027import org.openstreetmap.josm.data.osm.Way;
028import org.openstreetmap.josm.gui.HelpAwareOptionPane;
029import org.openstreetmap.josm.gui.HelpAwareOptionPane.ButtonSpec;
030import org.openstreetmap.josm.gui.Notification;
031import org.openstreetmap.josm.gui.help.HelpUtil;
032import org.openstreetmap.josm.tools.ImageProvider;
033import org.openstreetmap.josm.tools.Shortcut;
034
035/**
036 * Delete unnecessary nodes from a way
037 * @since 2575
038 */
039public class SimplifyWayAction extends JosmAction {
040    
041    /**
042     * Constructs a new {@code SimplifyWayAction}.
043     */
044    public SimplifyWayAction() {
045        super(tr("Simplify Way"), "simplify", tr("Delete unnecessary nodes from a way."), Shortcut.registerShortcut("tools:simplify", tr("Tool: {0}", tr("Simplify Way")),
046                KeyEvent.VK_Y, Shortcut.SHIFT), true);
047        putValue("help", ht("/Action/SimplifyWay"));
048    }
049
050    protected boolean confirmWayWithNodesOutsideBoundingBox(List<? extends OsmPrimitive> primitives) {
051        return DeleteCommand.checkAndConfirmOutlyingDelete(Main.main.getEditLayer(), primitives, null);
052    }
053
054    protected void alertSelectAtLeastOneWay() {
055        new Notification(
056                tr("Please select at least one way to simplify."))
057                .setIcon(JOptionPane.WARNING_MESSAGE)
058                .setDuration(Notification.TIME_SHORT)
059                .setHelpTopic(HelpUtil.ht("/Action/SimplifyWay#SelectAWayToSimplify"))
060                .show();
061    }
062
063    protected boolean confirmSimplifyManyWays(int numWays) {
064        ButtonSpec[] options = new ButtonSpec[] {
065                new ButtonSpec(
066                        tr("Yes"),
067                        ImageProvider.get("ok"),
068                        tr("Simplify all selected ways"),
069                        null
070                        ),
071                        new ButtonSpec(
072                                tr("Cancel"),
073                                ImageProvider.get("cancel"),
074                                tr("Cancel operation"),
075                                null
076                                )
077        };
078        int ret = HelpAwareOptionPane.showOptionDialog(
079                Main.parent,
080                tr(
081                        "The selection contains {0} ways. Are you sure you want to simplify them all?",
082                        numWays
083                        ),
084                        tr("Simplify ways?"),
085                        JOptionPane.WARNING_MESSAGE,
086                        null, // no special icon
087                        options,
088                        options[0],
089                        HelpUtil.ht("/Action/SimplifyWay#ConfirmSimplifyAll")
090                );
091        return ret == 0;
092    }
093
094    @Override
095    public void actionPerformed(ActionEvent e) {
096        DataSet ds = getCurrentDataSet();
097        ds.beginUpdate();
098        try
099        {
100            List<Way> ways = OsmPrimitive.getFilteredList(ds.getSelected(), Way.class);
101            if (ways.isEmpty()) {
102                alertSelectAtLeastOneWay();
103                return;
104            } else if (!confirmWayWithNodesOutsideBoundingBox(ways))
105                return;
106            else if (ways.size() > 10) {
107                if (!confirmSimplifyManyWays(ways.size()))
108                    return;
109            }
110
111            Collection<Command> allCommands = new LinkedList<Command>();
112            for (Way way: ways) {
113                SequenceCommand simplifyCommand = simplifyWay(way);
114                if (simplifyCommand == null) {
115                    continue;
116                }
117                allCommands.add(simplifyCommand);
118            }
119            if (allCommands.isEmpty()) return;
120            SequenceCommand rootCommand = new SequenceCommand(
121                    trn("Simplify {0} way", "Simplify {0} ways", allCommands.size(), allCommands.size()),
122                    allCommands
123                    );
124            Main.main.undoRedo.add(rootCommand);
125        } finally {
126            ds.endUpdate();
127        }
128        Main.map.repaint();
129    }
130
131    /**
132     * Replies true if <code>node</code> is a required node which can't be removed
133     * in order to simplify the way.
134     *
135     * @param way the way to be simplified
136     * @param node the node to check
137     * @return true if <code>node</code> is a required node which can't be removed
138     * in order to simplify the way.
139     */
140    protected boolean isRequiredNode(Way way, Node node) {
141        boolean isRequired =  Collections.frequency(way.getNodes(), node) > 1;
142        if (! isRequired) {
143            List<OsmPrimitive> parents = new LinkedList<OsmPrimitive>();
144            parents.addAll(node.getReferrers());
145            parents.remove(way);
146            isRequired = !parents.isEmpty();
147        }
148        if (!isRequired) {
149            isRequired = node.isTagged();
150        }
151        return isRequired;
152    }
153
154    /**
155     * Simplifies a way with default threshold (read from preferences).
156     *
157     * @param w the way to simplify
158     * @return The sequence of commands to run
159     * @since 6411
160     */
161    public final SequenceCommand simplifyWay(Way w) {
162        return simplifyWay(w, Main.pref.getDouble("simplify-way.max-error", 3.0));
163    }
164
165    /**
166     * Simplifies a way with a given threshold.
167     *
168     * @param w the way to simplify
169     * @return The sequence of commands to run
170     * @since 6411
171     */
172    public SequenceCommand simplifyWay(Way w, double threshold) {
173        int lower = 0;
174        int i = 0;
175        List<Node> newNodes = new ArrayList<Node>(w.getNodesCount());
176        while(i < w.getNodesCount()){
177            if (isRequiredNode(w,w.getNode(i))) {
178                // copy a required node to the list of new nodes. Simplify not possible
179                newNodes.add(w.getNode(i));
180                i++;
181                lower++;
182                continue;
183            }
184            i++;
185            // find the longest sequence of not required nodes ...
186            while(i<w.getNodesCount() && !isRequiredNode(w,w.getNode(i))) {
187                i++;
188            }
189            // ... and simplify them
190            buildSimplifiedNodeList(w.getNodes(), lower, Math.min(w.getNodesCount()-1, i), threshold,newNodes);
191            lower=i;
192            i++;
193        }
194
195        HashSet<Node> delNodes = new HashSet<Node>();
196        delNodes.addAll(w.getNodes());
197        delNodes.removeAll(newNodes);
198
199        if (delNodes.isEmpty()) return null;
200
201        Collection<Command> cmds = new LinkedList<Command>();
202        Way newWay = new Way(w);
203        newWay.setNodes(newNodes);
204        cmds.add(new ChangeCommand(w, newWay));
205        cmds.add(new DeleteCommand(delNodes));
206        w.getDataSet().clearSelection(delNodes);
207        return new SequenceCommand(trn("Simplify Way (remove {0} node)", "Simplify Way (remove {0} nodes)", delNodes.size(), delNodes.size()), cmds);
208    }
209
210    /**
211     * Builds the simplified list of nodes for a way segment given by a lower index <code>from</code>
212     * and an upper index <code>to</code>
213     *
214     * @param wnew the way to simplify
215     * @param from the lower index
216     * @param to the upper index
217     * @param threshold
218     */
219    protected void buildSimplifiedNodeList(List<Node> wnew, int from, int to, double threshold, List<Node> simplifiedNodes) {
220
221        Node fromN = wnew.get(from);
222        Node toN = wnew.get(to);
223
224        // Get max xte
225        int imax = -1;
226        double xtemax = 0;
227        for (int i = from + 1; i < to; i++) {
228            Node n = wnew.get(i);
229            double xte = Math.abs(EARTH_RAD
230                    * xtd(fromN.getCoor().lat() * Math.PI / 180, fromN.getCoor().lon() * Math.PI / 180, toN.getCoor().lat() * Math.PI
231                            / 180, toN.getCoor().lon() * Math.PI / 180, n.getCoor().lat() * Math.PI / 180, n.getCoor().lon() * Math.PI
232                            / 180));
233            if (xte > xtemax) {
234                xtemax = xte;
235                imax = i;
236            }
237        }
238
239        if (imax != -1 && xtemax >= threshold) {
240            // Segment cannot be simplified - try shorter segments
241            buildSimplifiedNodeList(wnew, from, imax,threshold,simplifiedNodes);
242            buildSimplifiedNodeList(wnew, imax, to, threshold,simplifiedNodes);
243        } else {
244            // Simplify segment
245            if (simplifiedNodes.isEmpty() || simplifiedNodes.get(simplifiedNodes.size()-1) != fromN) {
246                simplifiedNodes.add(fromN);
247            }
248            if (fromN != toN) {
249                simplifiedNodes.add(toN);
250            }
251        }
252    }
253
254    public static final double EARTH_RAD = 6378137.0;
255
256    /* From Aviaton Formulary v1.3
257     * http://williams.best.vwh.net/avform.htm
258     */
259    public static double dist(double lat1, double lon1, double lat2, double lon2) {
260        return 2 * Math.asin(Math.sqrt(Math.pow(Math.sin((lat1 - lat2) / 2), 2) + Math.cos(lat1) * Math.cos(lat2)
261                * Math.pow(Math.sin((lon1 - lon2) / 2), 2)));
262    }
263
264    public static double course(double lat1, double lon1, double lat2, double lon2) {
265        return Math.atan2(Math.sin(lon1 - lon2) * Math.cos(lat2), Math.cos(lat1) * Math.sin(lat2) - Math.sin(lat1)
266                * Math.cos(lat2) * Math.cos(lon1 - lon2))
267                % (2 * Math.PI);
268    }
269
270    public static double xtd(double lat1, double lon1, double lat2, double lon2, double lat3, double lon3) {
271        double dist_AD = dist(lat1, lon1, lat3, lon3);
272        double crs_AD = course(lat1, lon1, lat3, lon3);
273        double crs_AB = course(lat1, lon1, lat2, lon2);
274        return Math.asin(Math.sin(dist_AD) * Math.sin(crs_AD - crs_AB));
275    }
276
277    @Override
278    protected void updateEnabledState() {
279        if (getCurrentDataSet() == null) {
280            setEnabled(false);
281        } else {
282            updateEnabledState(getCurrentDataSet().getSelected());
283        }
284    }
285
286    @Override
287    protected void updateEnabledState(Collection<? extends OsmPrimitive> selection) {
288        setEnabled(selection != null && !selection.isEmpty());
289    }
290}