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.Arrays;
012import java.util.Collection;
013import java.util.Collections;
014import java.util.HashSet;
015import java.util.LinkedList;
016import java.util.List;
017import java.util.Set;
018
019import javax.swing.JOptionPane;
020import javax.swing.SwingUtilities;
021
022import org.openstreetmap.josm.Main;
023import org.openstreetmap.josm.command.ChangeCommand;
024import org.openstreetmap.josm.command.Command;
025import org.openstreetmap.josm.command.DeleteCommand;
026import org.openstreetmap.josm.command.SequenceCommand;
027import org.openstreetmap.josm.data.osm.DataSet;
028import org.openstreetmap.josm.data.osm.Node;
029import org.openstreetmap.josm.data.osm.OsmPrimitive;
030import org.openstreetmap.josm.data.osm.Way;
031import org.openstreetmap.josm.data.projection.Ellipsoid;
032import org.openstreetmap.josm.gui.HelpAwareOptionPane;
033import org.openstreetmap.josm.gui.HelpAwareOptionPane.ButtonSpec;
034import org.openstreetmap.josm.gui.MainApplication;
035import org.openstreetmap.josm.gui.Notification;
036import org.openstreetmap.josm.spi.preferences.Config;
037import org.openstreetmap.josm.tools.ImageProvider;
038import org.openstreetmap.josm.tools.Shortcut;
039
040/**
041 * Delete unnecessary nodes from a way
042 * @since 2575
043 */
044public class SimplifyWayAction extends JosmAction {
045
046    /**
047     * Constructs a new {@code SimplifyWayAction}.
048     */
049    public SimplifyWayAction() {
050        super(tr("Simplify Way"), "simplify", tr("Delete unnecessary nodes from a way."),
051                Shortcut.registerShortcut("tools:simplify", tr("Tool: {0}", tr("Simplify Way")), KeyEvent.VK_Y, Shortcut.SHIFT), true);
052        putValue("help", ht("/Action/SimplifyWay"));
053    }
054
055    protected boolean confirmWayWithNodesOutsideBoundingBox(List<? extends OsmPrimitive> primitives) {
056        return DeleteAction.checkAndConfirmOutlyingDelete(primitives, null);
057    }
058
059    protected void alertSelectAtLeastOneWay() {
060        SwingUtilities.invokeLater(() ->
061            new Notification(
062                    tr("Please select at least one way to simplify."))
063                    .setIcon(JOptionPane.WARNING_MESSAGE)
064                    .setDuration(Notification.TIME_SHORT)
065                    .setHelpTopic(ht("/Action/SimplifyWay#SelectAWayToSimplify"))
066                    .show()
067        );
068    }
069
070    protected boolean confirmSimplifyManyWays(int numWays) {
071        ButtonSpec[] options = new ButtonSpec[] {
072                new ButtonSpec(
073                        tr("Yes"),
074                        ImageProvider.get("ok"),
075                        tr("Simplify all selected ways"),
076                        null
077                        ),
078                        new ButtonSpec(
079                                tr("Cancel"),
080                                ImageProvider.get("cancel"),
081                                tr("Cancel operation"),
082                                null
083                                )
084        };
085        return 0 == HelpAwareOptionPane.showOptionDialog(
086                Main.parent,
087                tr(
088                        "The selection contains {0} ways. Are you sure you want to simplify them all?",
089                        numWays
090                        ),
091                        tr("Simplify ways?"),
092                        JOptionPane.WARNING_MESSAGE,
093                        null, // no special icon
094                        options,
095                        options[0],
096                        ht("/Action/SimplifyWay#ConfirmSimplifyAll")
097                );
098    }
099
100    @Override
101    public void actionPerformed(ActionEvent e) {
102        DataSet ds = getLayerManager().getEditDataSet();
103        ds.beginUpdate();
104        try {
105            List<Way> ways = OsmPrimitive.getFilteredList(ds.getSelected(), Way.class);
106            ways.removeIf(OsmPrimitive::isIncomplete);
107            if (ways.isEmpty()) {
108                alertSelectAtLeastOneWay();
109                return;
110            } else if (!confirmWayWithNodesOutsideBoundingBox(ways) || (ways.size() > 10 && !confirmSimplifyManyWays(ways.size()))) {
111                return;
112            }
113
114            Collection<Command> allCommands = new LinkedList<>();
115            for (Way way: ways) {
116                SequenceCommand simplifyCommand = simplifyWay(way);
117                if (simplifyCommand == null) {
118                    continue;
119                }
120                allCommands.add(simplifyCommand);
121            }
122            if (allCommands.isEmpty()) return;
123            SequenceCommand rootCommand = new SequenceCommand(
124                    trn("Simplify {0} way", "Simplify {0} ways", allCommands.size(), allCommands.size()),
125                    allCommands
126                    );
127            MainApplication.undoRedo.add(rootCommand);
128        } finally {
129            ds.endUpdate();
130        }
131    }
132
133    /**
134     * Replies true if <code>node</code> is a required node which can't be removed
135     * in order to simplify the way.
136     *
137     * @param way the way to be simplified
138     * @param node the node to check
139     * @return true if <code>node</code> is a required node which can't be removed
140     * in order to simplify the way.
141     */
142    protected static boolean isRequiredNode(Way way, Node node) {
143        boolean isRequired = node.isTagged();
144        if (!isRequired) {
145            int frequency = Collections.frequency(way.getNodes(), node);
146            if ((way.getNode(0) == node) && (way.getNode(way.getNodesCount()-1) == node)) {
147                frequency = frequency - 1; // closed way closing node counted only once
148            }
149            isRequired = frequency > 1;
150        }
151        if (!isRequired) {
152            List<OsmPrimitive> parents = new LinkedList<>();
153            parents.addAll(node.getReferrers());
154            parents.remove(way);
155            isRequired = !parents.isEmpty();
156        }
157        return isRequired;
158    }
159
160    /**
161     * Simplifies a way with default threshold (read from preferences).
162     *
163     * @param w the way to simplify
164     * @return The sequence of commands to run
165     * @since 6411
166     */
167    public final SequenceCommand simplifyWay(Way w) {
168        return simplifyWay(w, Config.getPref().getDouble("simplify-way.max-error", 3.0));
169    }
170
171    /**
172     * Simplifies a way with a given threshold.
173     *
174     * @param w the way to simplify
175     * @param threshold the max error threshold
176     * @return The sequence of commands to run
177     * @since 6411
178     */
179    public static SequenceCommand simplifyWay(Way w, double threshold) {
180        int lower = 0;
181        int i = 0;
182        List<Node> newNodes = new ArrayList<>(w.getNodesCount());
183        while (i < w.getNodesCount()) {
184            if (isRequiredNode(w, w.getNode(i))) {
185                // copy a required node to the list of new nodes. Simplify not possible
186                newNodes.add(w.getNode(i));
187                i++;
188                lower++;
189                continue;
190            }
191            i++;
192            // find the longest sequence of not required nodes ...
193            while (i < w.getNodesCount() && !isRequiredNode(w, w.getNode(i))) {
194                i++;
195            }
196            // ... and simplify them
197            buildSimplifiedNodeList(w.getNodes(), lower, Math.min(w.getNodesCount()-1, i), threshold, newNodes);
198            lower = i;
199            i++;
200        }
201
202        // Closed way, check if the first node could also be simplified ...
203        if (newNodes.size() > 3 && newNodes.get(0) == newNodes.get(newNodes.size() - 1) && !isRequiredNode(w, newNodes.get(0))) {
204            final List<Node> l1 = Arrays.asList(newNodes.get(newNodes.size() - 2), newNodes.get(0), newNodes.get(1));
205            final List<Node> l2 = new ArrayList<>(3);
206            buildSimplifiedNodeList(l1, 0, 2, threshold, l2);
207            if (!l2.contains(newNodes.get(0))) {
208                newNodes.remove(0);
209                newNodes.set(newNodes.size() - 1, newNodes.get(0)); // close the way
210            }
211        }
212
213        if (newNodes.size() == w.getNodesCount()) return null;
214
215        Set<Node> delNodes = new HashSet<>();
216        delNodes.addAll(w.getNodes());
217        delNodes.removeAll(newNodes);
218
219        if (delNodes.isEmpty()) return null;
220
221        Collection<Command> cmds = new LinkedList<>();
222        Way newWay = new Way(w);
223        newWay.setNodes(newNodes);
224        cmds.add(new ChangeCommand(w, newWay));
225        cmds.add(new DeleteCommand(w.getDataSet(), delNodes));
226        w.getDataSet().clearSelection(delNodes);
227        return new SequenceCommand(
228                trn("Simplify Way (remove {0} node)", "Simplify Way (remove {0} nodes)", delNodes.size(), delNodes.size()), cmds);
229    }
230
231    /**
232     * Builds the simplified list of nodes for a way segment given by a lower index <code>from</code>
233     * and an upper index <code>to</code>
234     *
235     * @param wnew the way to simplify
236     * @param from the lower index
237     * @param to the upper index
238     * @param threshold the max error threshold
239     * @param simplifiedNodes list that will contain resulting nodes
240     */
241    protected static void buildSimplifiedNodeList(List<Node> wnew, int from, int to, double threshold, List<Node> simplifiedNodes) {
242
243        Node fromN = wnew.get(from);
244        Node toN = wnew.get(to);
245
246        // Get max xte
247        int imax = -1;
248        double xtemax = 0;
249        for (int i = from + 1; i < to; i++) {
250            Node n = wnew.get(i);
251            // CHECKSTYLE.OFF: SingleSpaceSeparator
252            double xte = Math.abs(Ellipsoid.WGS84.a
253                    * xtd(fromN.lat() * Math.PI / 180, fromN.lon() * Math.PI / 180, toN.lat() * Math.PI / 180,
254                            toN.lon() * Math.PI / 180,     n.lat() * Math.PI / 180,   n.lon() * Math.PI / 180));
255            // CHECKSTYLE.ON: SingleSpaceSeparator
256            if (xte > xtemax) {
257                xtemax = xte;
258                imax = i;
259            }
260        }
261
262        if (imax != -1 && xtemax >= threshold) {
263            // Segment cannot be simplified - try shorter segments
264            buildSimplifiedNodeList(wnew, from, imax, threshold, simplifiedNodes);
265            buildSimplifiedNodeList(wnew, imax, to, threshold, simplifiedNodes);
266        } else {
267            // Simplify segment
268            if (simplifiedNodes.isEmpty() || simplifiedNodes.get(simplifiedNodes.size()-1) != fromN) {
269                simplifiedNodes.add(fromN);
270            }
271            if (fromN != toN) {
272                simplifiedNodes.add(toN);
273            }
274        }
275    }
276
277    /* From Aviaton Formulary v1.3
278     * http://williams.best.vwh.net/avform.htm
279     */
280    private static double dist(double lat1, double lon1, double lat2, double lon2) {
281        return 2 * Math.asin(Math.sqrt(Math.pow(Math.sin((lat1 - lat2) / 2), 2) + Math.cos(lat1) * Math.cos(lat2)
282                * Math.pow(Math.sin((lon1 - lon2) / 2), 2)));
283    }
284
285    private static double course(double lat1, double lon1, double lat2, double lon2) {
286        return Math.atan2(Math.sin(lon1 - lon2) * Math.cos(lat2), Math.cos(lat1) * Math.sin(lat2) - Math.sin(lat1)
287                * Math.cos(lat2) * Math.cos(lon1 - lon2))
288                % (2 * Math.PI);
289    }
290
291    private static double xtd(double lat1, double lon1, double lat2, double lon2, double lat3, double lon3) {
292        double distAD = dist(lat1, lon1, lat3, lon3);
293        double crsAD = course(lat1, lon1, lat3, lon3);
294        double crsAB = course(lat1, lon1, lat2, lon2);
295        return Math.asin(Math.sin(distAD) * Math.sin(crsAD - crsAB));
296    }
297
298    @Override
299    protected void updateEnabledState() {
300        updateEnabledStateOnCurrentSelection();
301    }
302
303    @Override
304    protected void updateEnabledState(Collection<? extends OsmPrimitive> selection) {
305        updateEnabledStateOnModifiableSelection(selection);
306    }
307}