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.gui.HelpAwareOptionPane;
030import org.openstreetmap.josm.gui.HelpAwareOptionPane.ButtonSpec;
031import org.openstreetmap.josm.gui.Notification;
032import org.openstreetmap.josm.gui.help.HelpUtil;
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(HelpUtil.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        int ret = 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                        HelpUtil.ht("/Action/SimplifyWay#ConfirmSimplifyAll")
091                );
092        return ret == 0;
093    }
094
095    @Override
096    public void actionPerformed(ActionEvent e) {
097        DataSet ds = getCurrentDataSet();
098        ds.beginUpdate();
099        try {
100            List<Way> ways = OsmPrimitive.getFilteredList(ds.getSelected(), Way.class);
101            if (ways.isEmpty()) {
102                alertSelectAtLeastOneWay();
103                return;
104            } else if (!confirmWayWithNodesOutsideBoundingBox(ways)) {
105                return;
106            } else if (ways.size() > 10 && !confirmSimplifyManyWays(ways.size())) {
107                return;
108            }
109
110            Collection<Command> allCommands = new LinkedList<>();
111            for (Way way: ways) {
112                SequenceCommand simplifyCommand = simplifyWay(way);
113                if (simplifyCommand == null) {
114                    continue;
115                }
116                allCommands.add(simplifyCommand);
117            }
118            if (allCommands.isEmpty()) return;
119            SequenceCommand rootCommand = new SequenceCommand(
120                    trn("Simplify {0} way", "Simplify {0} ways", allCommands.size(), allCommands.size()),
121                    allCommands
122                    );
123            Main.main.undoRedo.add(rootCommand);
124        } finally {
125            ds.endUpdate();
126        }
127        Main.map.repaint();
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 boolean isRequiredNode(Way way, Node node) {
140        boolean isRequired =  Collections.frequency(way.getNodes(), node) > 1;
141        if (!isRequired) {
142            List<OsmPrimitive> parents = new LinkedList<>();
143            parents.addAll(node.getReferrers());
144            parents.remove(way);
145            isRequired = !parents.isEmpty();
146        }
147        if (!isRequired) {
148            isRequired = node.isTagged();
149        }
150        return isRequired;
151    }
152
153    /**
154     * Simplifies a way with default threshold (read from preferences).
155     *
156     * @param w the way to simplify
157     * @return The sequence of commands to run
158     * @since 6411
159     */
160    public final SequenceCommand simplifyWay(Way w) {
161        return simplifyWay(w, Main.pref.getDouble("simplify-way.max-error", 3.0));
162    }
163
164    /**
165     * Simplifies a way with a given threshold.
166     *
167     * @param w the way to simplify
168     * @param threshold the max error threshold
169     * @return The sequence of commands to run
170     * @since 6411
171     */
172    public SequenceCommand simplifyWay(Way w, double threshold) {
173        int lower = 0;
174        int i = 0;
175        List<Node> newNodes = new ArrayList<>(w.getNodesCount());
176        while (i < w.getNodesCount()) {
177            if (isRequiredNode(w, w.getNode(i))) {
178                // copy a required node to the list of new nodes. Simplify not possible
179                newNodes.add(w.getNode(i));
180                i++;
181                lower++;
182                continue;
183            }
184            i++;
185            // find the longest sequence of not required nodes ...
186            while (i < w.getNodesCount() && !isRequiredNode(w, w.getNode(i))) {
187                i++;
188            }
189            // ... and simplify them
190            buildSimplifiedNodeList(w.getNodes(), lower, Math.min(w.getNodesCount()-1, i), threshold, newNodes);
191            lower = i;
192            i++;
193        }
194
195        Set<Node> delNodes = new HashSet<>();
196        delNodes.addAll(w.getNodes());
197        delNodes.removeAll(newNodes);
198
199        if (delNodes.isEmpty()) return null;
200
201        Collection<Command> cmds = new LinkedList<>();
202        Way newWay = new Way(w);
203        newWay.setNodes(newNodes);
204        cmds.add(new ChangeCommand(w, newWay));
205        cmds.add(new DeleteCommand(delNodes));
206        w.getDataSet().clearSelection(delNodes);
207        return new SequenceCommand(
208                trn("Simplify Way (remove {0} node)", "Simplify Way (remove {0} nodes)", delNodes.size(), delNodes.size()), cmds);
209    }
210
211    /**
212     * Builds the simplified list of nodes for a way segment given by a lower index <code>from</code>
213     * and an upper index <code>to</code>
214     *
215     * @param wnew the way to simplify
216     * @param from the lower index
217     * @param to the upper index
218     * @param threshold the max error threshold
219     */
220    protected void buildSimplifiedNodeList(List<Node> wnew, int from, int to, double threshold, List<Node> simplifiedNodes) {
221
222        Node fromN = wnew.get(from);
223        Node toN = wnew.get(to);
224
225        // Get max xte
226        int imax = -1;
227        double xtemax = 0;
228        for (int i = from + 1; i < to; i++) {
229            Node n = wnew.get(i);
230            double xte = Math.abs(EARTH_RAD
231                    * xtd(fromN.getCoor().lat() * Math.PI / 180, fromN.getCoor().lon() * Math.PI / 180, toN.getCoor().lat() * Math.PI
232                            / 180, toN.getCoor().lon() * Math.PI / 180, n.getCoor().lat() * Math.PI / 180, n.getCoor().lon() * Math.PI
233                            / 180));
234            if (xte > xtemax) {
235                xtemax = xte;
236                imax = i;
237            }
238        }
239
240        if (imax != -1 && xtemax >= threshold) {
241            // Segment cannot be simplified - try shorter segments
242            buildSimplifiedNodeList(wnew, from, imax, threshold, simplifiedNodes);
243            buildSimplifiedNodeList(wnew, imax, to, threshold, simplifiedNodes);
244        } else {
245            // Simplify segment
246            if (simplifiedNodes.isEmpty() || simplifiedNodes.get(simplifiedNodes.size()-1) != fromN) {
247                simplifiedNodes.add(fromN);
248            }
249            if (fromN != toN) {
250                simplifiedNodes.add(toN);
251            }
252        }
253    }
254
255    public static final double EARTH_RAD = 6378137.0;
256
257    /* From Aviaton Formulary v1.3
258     * http://williams.best.vwh.net/avform.htm
259     */
260    public static double dist(double lat1, double lon1, double lat2, double lon2) {
261        return 2 * Math.asin(Math.sqrt(Math.pow(Math.sin((lat1 - lat2) / 2), 2) + Math.cos(lat1) * Math.cos(lat2)
262                * Math.pow(Math.sin((lon1 - lon2) / 2), 2)));
263    }
264
265    public static double course(double lat1, double lon1, double lat2, double lon2) {
266        return Math.atan2(Math.sin(lon1 - lon2) * Math.cos(lat2), Math.cos(lat1) * Math.sin(lat2) - Math.sin(lat1)
267                * Math.cos(lat2) * Math.cos(lon1 - lon2))
268                % (2 * Math.PI);
269    }
270
271    public static double xtd(double lat1, double lon1, double lat2, double lon2, double lat3, double lon3) {
272        double distAD = dist(lat1, lon1, lat3, lon3);
273        double crsAD = course(lat1, lon1, lat3, lon3);
274        double crsAB = course(lat1, lon1, lat2, lon2);
275        return Math.asin(Math.sin(distAD) * Math.sin(crsAD - crsAB));
276    }
277
278    @Override
279    protected void updateEnabledState() {
280        if (getCurrentDataSet() == null) {
281            setEnabled(false);
282        } else {
283            updateEnabledState(getCurrentDataSet().getSelected());
284        }
285    }
286
287    @Override
288    protected void updateEnabledState(Collection<? extends OsmPrimitive> selection) {
289        setEnabled(selection != null && !selection.isEmpty());
290    }
291}