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