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(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            List<Way> ways = OsmPrimitive.getFilteredList(ds.getSelected(), Way.class);
100            if (ways.isEmpty()) {
101                alertSelectAtLeastOneWay();
102                return;
103            } else if (!confirmWayWithNodesOutsideBoundingBox(ways)) {
104                return;
105            } else if (ways.size() > 10 && !confirmSimplifyManyWays(ways.size())) {
106                return;
107            }
108
109            Collection<Command> allCommands = new LinkedList<>();
110            for (Way way: ways) {
111                SequenceCommand simplifyCommand = simplifyWay(way);
112                if (simplifyCommand == null) {
113                    continue;
114                }
115                allCommands.add(simplifyCommand);
116            }
117            if (allCommands.isEmpty()) return;
118            SequenceCommand rootCommand = new SequenceCommand(
119                    trn("Simplify {0} way", "Simplify {0} ways", allCommands.size(), allCommands.size()),
120                    allCommands
121                    );
122            Main.main.undoRedo.add(rootCommand);
123        } finally {
124            ds.endUpdate();
125        }
126        Main.map.repaint();
127    }
128
129    /**
130     * Replies true if <code>node</code> is a required node which can't be removed
131     * in order to simplify the way.
132     *
133     * @param way the way to be simplified
134     * @param node the node to check
135     * @return true if <code>node</code> is a required node which can't be removed
136     * in order to simplify the way.
137     */
138    protected boolean isRequiredNode(Way way, Node node) {
139        boolean isRequired =  Collections.frequency(way.getNodes(), node) > 1;
140        if (! isRequired) {
141            List<OsmPrimitive> parents = new LinkedList<>();
142            parents.addAll(node.getReferrers());
143            parents.remove(way);
144            isRequired = !parents.isEmpty();
145        }
146        if (!isRequired) {
147            isRequired = node.isTagged();
148        }
149        return isRequired;
150    }
151
152    /**
153     * Simplifies a way with default threshold (read from preferences).
154     *
155     * @param w the way to simplify
156     * @return The sequence of commands to run
157     * @since 6411
158     */
159    public final SequenceCommand simplifyWay(Way w) {
160        return simplifyWay(w, Main.pref.getDouble("simplify-way.max-error", 3.0));
161    }
162
163    /**
164     * Simplifies a way with a given threshold.
165     *
166     * @param w the way to simplify
167     * @return The sequence of commands to run
168     * @since 6411
169     */
170    public SequenceCommand simplifyWay(Way w, double threshold) {
171        int lower = 0;
172        int i = 0;
173        List<Node> newNodes = new ArrayList<>(w.getNodesCount());
174        while(i < w.getNodesCount()){
175            if (isRequiredNode(w,w.getNode(i))) {
176                // copy a required node to the list of new nodes. Simplify not possible
177                newNodes.add(w.getNode(i));
178                i++;
179                lower++;
180                continue;
181            }
182            i++;
183            // find the longest sequence of not required nodes ...
184            while(i<w.getNodesCount() && !isRequiredNode(w,w.getNode(i))) {
185                i++;
186            }
187            // ... and simplify them
188            buildSimplifiedNodeList(w.getNodes(), lower, Math.min(w.getNodesCount()-1, i), threshold,newNodes);
189            lower=i;
190            i++;
191        }
192
193        HashSet<Node> delNodes = new HashSet<>();
194        delNodes.addAll(w.getNodes());
195        delNodes.removeAll(newNodes);
196
197        if (delNodes.isEmpty()) return null;
198
199        Collection<Command> cmds = new LinkedList<>();
200        Way newWay = new Way(w);
201        newWay.setNodes(newNodes);
202        cmds.add(new ChangeCommand(w, newWay));
203        cmds.add(new DeleteCommand(delNodes));
204        w.getDataSet().clearSelection(delNodes);
205        return new SequenceCommand(trn("Simplify Way (remove {0} node)", "Simplify Way (remove {0} nodes)", delNodes.size(), delNodes.size()), cmds);
206    }
207
208    /**
209     * Builds the simplified list of nodes for a way segment given by a lower index <code>from</code>
210     * and an upper index <code>to</code>
211     *
212     * @param wnew the way to simplify
213     * @param from the lower index
214     * @param to the upper index
215     * @param threshold
216     */
217    protected void buildSimplifiedNodeList(List<Node> wnew, int from, int to, double threshold, List<Node> simplifiedNodes) {
218
219        Node fromN = wnew.get(from);
220        Node toN = wnew.get(to);
221
222        // Get max xte
223        int imax = -1;
224        double xtemax = 0;
225        for (int i = from + 1; i < to; i++) {
226            Node n = wnew.get(i);
227            double xte = Math.abs(EARTH_RAD
228                    * xtd(fromN.getCoor().lat() * Math.PI / 180, fromN.getCoor().lon() * Math.PI / 180, toN.getCoor().lat() * Math.PI
229                            / 180, toN.getCoor().lon() * Math.PI / 180, n.getCoor().lat() * Math.PI / 180, n.getCoor().lon() * Math.PI
230                            / 180));
231            if (xte > xtemax) {
232                xtemax = xte;
233                imax = i;
234            }
235        }
236
237        if (imax != -1 && xtemax >= threshold) {
238            // Segment cannot be simplified - try shorter segments
239            buildSimplifiedNodeList(wnew, from, imax,threshold,simplifiedNodes);
240            buildSimplifiedNodeList(wnew, imax, to, threshold,simplifiedNodes);
241        } else {
242            // Simplify segment
243            if (simplifiedNodes.isEmpty() || simplifiedNodes.get(simplifiedNodes.size()-1) != fromN) {
244                simplifiedNodes.add(fromN);
245            }
246            if (fromN != toN) {
247                simplifiedNodes.add(toN);
248            }
249        }
250    }
251
252    public static final double EARTH_RAD = 6378137.0;
253
254    /* From Aviaton Formulary v1.3
255     * http://williams.best.vwh.net/avform.htm
256     */
257    public static double dist(double lat1, double lon1, double lat2, double lon2) {
258        return 2 * Math.asin(Math.sqrt(Math.pow(Math.sin((lat1 - lat2) / 2), 2) + Math.cos(lat1) * Math.cos(lat2)
259                * Math.pow(Math.sin((lon1 - lon2) / 2), 2)));
260    }
261
262    public static double course(double lat1, double lon1, double lat2, double lon2) {
263        return Math.atan2(Math.sin(lon1 - lon2) * Math.cos(lat2), Math.cos(lat1) * Math.sin(lat2) - Math.sin(lat1)
264                * Math.cos(lat2) * Math.cos(lon1 - lon2))
265                % (2 * Math.PI);
266    }
267
268    public static double xtd(double lat1, double lon1, double lat2, double lon2, double lat3, double lon3) {
269        double distAD = dist(lat1, lon1, lat3, lon3);
270        double crsAD = course(lat1, lon1, lat3, lon3);
271        double crsAB = course(lat1, lon1, lat2, lon2);
272        return Math.asin(Math.sin(distAD) * Math.sin(crsAD - crsAB));
273    }
274
275    @Override
276    protected void updateEnabledState() {
277        if (getCurrentDataSet() == null) {
278            setEnabled(false);
279        } else {
280            updateEnabledState(getCurrentDataSet().getSelected());
281        }
282    }
283
284    @Override
285    protected void updateEnabledState(Collection<? extends OsmPrimitive> selection) {
286        setEnabled(selection != null && !selection.isEmpty());
287    }
288}