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                        new ImageProvider("ok"),
075                        tr("Simplify all selected ways"),
076                        null),
077                new ButtonSpec(
078                        tr("Cancel"),
079                        new ImageProvider("cancel"),
080                        tr("Cancel operation"),
081                        null)
082        };
083        return 0 == HelpAwareOptionPane.showOptionDialog(
084                Main.parent,
085                tr("The selection contains {0} ways. Are you sure you want to simplify them all?", numWays),
086                tr("Simplify ways?"),
087                JOptionPane.WARNING_MESSAGE,
088                null, // no special icon
089                options,
090                options[0],
091                ht("/Action/SimplifyWay#ConfirmSimplifyAll")
092                );
093    }
094
095    @Override
096    public void actionPerformed(ActionEvent e) {
097        DataSet ds = getLayerManager().getEditDataSet();
098        ds.beginUpdate();
099        try {
100            List<Way> ways = OsmPrimitive.getFilteredList(ds.getSelected(), Way.class);
101            ways.removeIf(OsmPrimitive::isIncomplete);
102            if (ways.isEmpty()) {
103                alertSelectAtLeastOneWay();
104                return;
105            } else if (!confirmWayWithNodesOutsideBoundingBox(ways) || (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            MainApplication.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 static boolean isRequiredNode(Way way, Node node) {
138        boolean isRequired = node.isTagged();
139        if (!isRequired) {
140            int frequency = Collections.frequency(way.getNodes(), node);
141            if ((way.getNode(0) == node) && (way.getNode(way.getNodesCount()-1) == node)) {
142                frequency = frequency - 1; // closed way closing node counted only once
143            }
144            isRequired = frequency > 1;
145        }
146        if (!isRequired) {
147            List<OsmPrimitive> parents = new LinkedList<>();
148            parents.addAll(node.getReferrers());
149            parents.remove(way);
150            isRequired = !parents.isEmpty();
151        }
152        return isRequired;
153    }
154
155    /**
156     * Simplifies a way with default threshold (read from preferences).
157     *
158     * @param w the way to simplify
159     * @return The sequence of commands to run
160     * @since 6411
161     */
162    public final SequenceCommand simplifyWay(Way w) {
163        return simplifyWay(w, Config.getPref().getDouble("simplify-way.max-error", 3.0));
164    }
165
166    /**
167     * Simplifies a way with a given threshold.
168     *
169     * @param w the way to simplify
170     * @param threshold the max error threshold
171     * @return The sequence of commands to run
172     * @since 6411
173     */
174    public static SequenceCommand simplifyWay(Way w, double threshold) {
175        int lower = 0;
176        int i = 0;
177        List<Node> newNodes = new ArrayList<>(w.getNodesCount());
178        while (i < w.getNodesCount()) {
179            if (isRequiredNode(w, w.getNode(i))) {
180                // copy a required node to the list of new nodes. Simplify not possible
181                newNodes.add(w.getNode(i));
182                i++;
183                lower++;
184                continue;
185            }
186            i++;
187            // find the longest sequence of not required nodes ...
188            while (i < w.getNodesCount() && !isRequiredNode(w, w.getNode(i))) {
189                i++;
190            }
191            // ... and simplify them
192            buildSimplifiedNodeList(w.getNodes(), lower, Math.min(w.getNodesCount()-1, i), threshold, newNodes);
193            lower = i;
194            i++;
195        }
196
197        // Closed way, check if the first node could also be simplified ...
198        if (newNodes.size() > 3 && newNodes.get(0) == newNodes.get(newNodes.size() - 1) && !isRequiredNode(w, newNodes.get(0))) {
199            final List<Node> l1 = Arrays.asList(newNodes.get(newNodes.size() - 2), newNodes.get(0), newNodes.get(1));
200            final List<Node> l2 = new ArrayList<>(3);
201            buildSimplifiedNodeList(l1, 0, 2, threshold, l2);
202            if (!l2.contains(newNodes.get(0))) {
203                newNodes.remove(0);
204                newNodes.set(newNodes.size() - 1, newNodes.get(0)); // close the way
205            }
206        }
207
208        if (newNodes.size() == w.getNodesCount()) return null;
209
210        Set<Node> delNodes = new HashSet<>();
211        delNodes.addAll(w.getNodes());
212        delNodes.removeAll(newNodes);
213
214        if (delNodes.isEmpty()) return null;
215
216        Collection<Command> cmds = new LinkedList<>();
217        Way newWay = new Way(w);
218        newWay.setNodes(newNodes);
219        cmds.add(new ChangeCommand(w, newWay));
220        cmds.add(new DeleteCommand(w.getDataSet(), delNodes));
221        w.getDataSet().clearSelection(delNodes);
222        return new SequenceCommand(
223                trn("Simplify Way (remove {0} node)", "Simplify Way (remove {0} nodes)", delNodes.size(), delNodes.size()), cmds);
224    }
225
226    /**
227     * Builds the simplified list of nodes for a way segment given by a lower index <code>from</code>
228     * and an upper index <code>to</code>
229     *
230     * @param wnew the way to simplify
231     * @param from the lower index
232     * @param to the upper index
233     * @param threshold the max error threshold
234     * @param simplifiedNodes list that will contain resulting nodes
235     */
236    protected static void buildSimplifiedNodeList(List<Node> wnew, int from, int to, double threshold, List<Node> simplifiedNodes) {
237
238        Node fromN = wnew.get(from);
239        Node toN = wnew.get(to);
240
241        // Get max xte
242        int imax = -1;
243        double xtemax = 0;
244        for (int i = from + 1; i < to; i++) {
245            Node n = wnew.get(i);
246            // CHECKSTYLE.OFF: SingleSpaceSeparator
247            double xte = Math.abs(Ellipsoid.WGS84.a
248                    * xtd(fromN.lat() * Math.PI / 180, fromN.lon() * Math.PI / 180, toN.lat() * Math.PI / 180,
249                            toN.lon() * Math.PI / 180,     n.lat() * Math.PI / 180,   n.lon() * Math.PI / 180));
250            // CHECKSTYLE.ON: SingleSpaceSeparator
251            if (xte > xtemax) {
252                xtemax = xte;
253                imax = i;
254            }
255        }
256
257        if (imax != -1 && xtemax >= threshold) {
258            // Segment cannot be simplified - try shorter segments
259            buildSimplifiedNodeList(wnew, from, imax, threshold, simplifiedNodes);
260            buildSimplifiedNodeList(wnew, imax, to, threshold, simplifiedNodes);
261        } else {
262            // Simplify segment
263            if (simplifiedNodes.isEmpty() || simplifiedNodes.get(simplifiedNodes.size()-1) != fromN) {
264                simplifiedNodes.add(fromN);
265            }
266            if (fromN != toN) {
267                simplifiedNodes.add(toN);
268            }
269        }
270    }
271
272    /* From Aviaton Formulary v1.3
273     * http://williams.best.vwh.net/avform.htm
274     */
275    private static double dist(double lat1, double lon1, double lat2, double lon2) {
276        return 2 * Math.asin(Math.sqrt(Math.pow(Math.sin((lat1 - lat2) / 2), 2) + Math.cos(lat1) * Math.cos(lat2)
277                * Math.pow(Math.sin((lon1 - lon2) / 2), 2)));
278    }
279
280    private static double course(double lat1, double lon1, double lat2, double lon2) {
281        return Math.atan2(Math.sin(lon1 - lon2) * Math.cos(lat2), Math.cos(lat1) * Math.sin(lat2) - Math.sin(lat1)
282                * Math.cos(lat2) * Math.cos(lon1 - lon2))
283                % (2 * Math.PI);
284    }
285
286    private static double xtd(double lat1, double lon1, double lat2, double lon2, double lat3, double lon3) {
287        double distAD = dist(lat1, lon1, lat3, lon3);
288        double crsAD = course(lat1, lon1, lat3, lon3);
289        double crsAB = course(lat1, lon1, lat2, lon2);
290        return Math.asin(Math.sin(distAD) * Math.sin(crsAD - crsAB));
291    }
292
293    @Override
294    protected void updateEnabledState() {
295        updateEnabledStateOnCurrentSelection();
296    }
297
298    @Override
299    protected void updateEnabledState(Collection<? extends OsmPrimitive> selection) {
300        updateEnabledStateOnModifiableSelection(selection);
301    }
302}