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;
016import java.util.Set;
017
018import javax.swing.JOptionPane;
019
020import org.openstreetmap.josm.Main;
021import org.openstreetmap.josm.command.ChangeCommand;
022import org.openstreetmap.josm.command.Command;
023import org.openstreetmap.josm.command.DeleteCommand;
024import org.openstreetmap.josm.command.SequenceCommand;
025import org.openstreetmap.josm.data.osm.DataSet;
026import org.openstreetmap.josm.data.osm.Node;
027import org.openstreetmap.josm.data.osm.OsmPrimitive;
028import org.openstreetmap.josm.data.osm.Way;
029import org.openstreetmap.josm.data.projection.Ellipsoid;
030import org.openstreetmap.josm.gui.HelpAwareOptionPane;
031import org.openstreetmap.josm.gui.HelpAwareOptionPane.ButtonSpec;
032import org.openstreetmap.josm.gui.Notification;
033import org.openstreetmap.josm.tools.ImageProvider;
034import org.openstreetmap.josm.tools.Shortcut;
035
036/**
037 * Delete unnecessary nodes from a way
038 * @since 2575
039 */
040public class SimplifyWayAction extends JosmAction {
041
042    /**
043     * Constructs a new {@code SimplifyWayAction}.
044     */
045    public SimplifyWayAction() {
046        super(tr("Simplify Way"), "simplify", tr("Delete unnecessary nodes from a way."),
047                Shortcut.registerShortcut("tools:simplify", tr("Tool: {0}", tr("Simplify Way")), KeyEvent.VK_Y, Shortcut.SHIFT), true);
048        putValue("help", ht("/Action/SimplifyWay"));
049    }
050
051    protected boolean confirmWayWithNodesOutsideBoundingBox(List<? extends OsmPrimitive> primitives) {
052        return DeleteCommand.checkAndConfirmOutlyingDelete(primitives, null);
053    }
054
055    protected void alertSelectAtLeastOneWay() {
056        new Notification(
057                tr("Please select at least one way to simplify."))
058                .setIcon(JOptionPane.WARNING_MESSAGE)
059                .setDuration(Notification.TIME_SHORT)
060                .setHelpTopic(ht("/Action/SimplifyWay#SelectAWayToSimplify"))
061                .show();
062    }
063
064    protected boolean confirmSimplifyManyWays(int numWays) {
065        ButtonSpec[] options = new ButtonSpec[] {
066                new ButtonSpec(
067                        tr("Yes"),
068                        ImageProvider.get("ok"),
069                        tr("Simplify all selected ways"),
070                        null
071                        ),
072                        new ButtonSpec(
073                                tr("Cancel"),
074                                ImageProvider.get("cancel"),
075                                tr("Cancel operation"),
076                                null
077                                )
078        };
079        return 0 == HelpAwareOptionPane.showOptionDialog(
080                Main.parent,
081                tr(
082                        "The selection contains {0} ways. Are you sure you want to simplify them all?",
083                        numWays
084                        ),
085                        tr("Simplify ways?"),
086                        JOptionPane.WARNING_MESSAGE,
087                        null, // no special icon
088                        options,
089                        options[0],
090                        ht("/Action/SimplifyWay#ConfirmSimplifyAll")
091                );
092    }
093
094    @Override
095    public void actionPerformed(ActionEvent e) {
096        DataSet ds = getLayerManager().getEditDataSet();
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    }
127
128    /**
129     * Replies true if <code>node</code> is a required node which can't be removed
130     * in order to simplify the way.
131     *
132     * @param way the way to be simplified
133     * @param node the node to check
134     * @return true if <code>node</code> is a required node which can't be removed
135     * in order to simplify the way.
136     */
137    protected boolean isRequiredNode(Way way, Node node) {
138        boolean isRequired = Collections.frequency(way.getNodes(), node) > 1;
139        if (!isRequired) {
140            List<OsmPrimitive> parents = new LinkedList<>();
141            parents.addAll(node.getReferrers());
142            parents.remove(way);
143            isRequired = !parents.isEmpty();
144        }
145        if (!isRequired) {
146            isRequired = node.isTagged();
147        }
148        return isRequired;
149    }
150
151    /**
152     * Simplifies a way with default threshold (read from preferences).
153     *
154     * @param w the way to simplify
155     * @return The sequence of commands to run
156     * @since 6411
157     */
158    public final SequenceCommand simplifyWay(Way w) {
159        return simplifyWay(w, Main.pref.getDouble("simplify-way.max-error", 3.0));
160    }
161
162    /**
163     * Simplifies a way with a given threshold.
164     *
165     * @param w the way to simplify
166     * @param threshold the max error threshold
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        Set<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(
206                trn("Simplify Way (remove {0} node)", "Simplify Way (remove {0} nodes)", delNodes.size(), delNodes.size()), cmds);
207    }
208
209    /**
210     * Builds the simplified list of nodes for a way segment given by a lower index <code>from</code>
211     * and an upper index <code>to</code>
212     *
213     * @param wnew the way to simplify
214     * @param from the lower index
215     * @param to the upper index
216     * @param threshold the max error threshold
217     * @param simplifiedNodes list that will contain resulting nodes
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(Ellipsoid.WGS84.a
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    /* 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        updateEnabledStateOnCurrentSelection();
278    }
279
280    @Override
281    protected void updateEnabledState(Collection<? extends OsmPrimitive> selection) {
282        setEnabled(selection != null && !selection.isEmpty());
283    }
284}