001// License: GPL. For details, see LICENSE file.
002package org.openstreetmap.josm.actions.mapmode;
003
004import static org.openstreetmap.josm.gui.help.HelpUtil.ht;
005import static org.openstreetmap.josm.tools.I18n.marktr;
006import static org.openstreetmap.josm.tools.I18n.tr;
007import static org.openstreetmap.josm.tools.I18n.trn;
008
009import java.awt.BasicStroke;
010import java.awt.Color;
011import java.awt.Cursor;
012import java.awt.Graphics2D;
013import java.awt.Point;
014import java.awt.event.ActionEvent;
015import java.awt.event.KeyEvent;
016import java.awt.event.MouseEvent;
017import java.util.ArrayList;
018import java.util.Collection;
019import java.util.Collections;
020import java.util.HashMap;
021import java.util.HashSet;
022import java.util.Iterator;
023import java.util.LinkedList;
024import java.util.List;
025import java.util.Map;
026import java.util.Set;
027
028import javax.swing.AbstractAction;
029import javax.swing.JCheckBoxMenuItem;
030import javax.swing.JMenuItem;
031import javax.swing.JOptionPane;
032import javax.swing.SwingUtilities;
033
034import org.openstreetmap.josm.Main;
035import org.openstreetmap.josm.actions.JosmAction;
036import org.openstreetmap.josm.command.AddCommand;
037import org.openstreetmap.josm.command.ChangeCommand;
038import org.openstreetmap.josm.command.Command;
039import org.openstreetmap.josm.command.SequenceCommand;
040import org.openstreetmap.josm.data.Bounds;
041import org.openstreetmap.josm.data.coor.EastNorth;
042import org.openstreetmap.josm.data.osm.DataSelectionListener;
043import org.openstreetmap.josm.data.osm.DataSet;
044import org.openstreetmap.josm.data.osm.Node;
045import org.openstreetmap.josm.data.osm.OsmPrimitive;
046import org.openstreetmap.josm.data.osm.Way;
047import org.openstreetmap.josm.data.osm.WaySegment;
048import org.openstreetmap.josm.data.osm.event.SelectionEventManager;
049import org.openstreetmap.josm.data.osm.visitor.paint.ArrowPaintHelper;
050import org.openstreetmap.josm.data.osm.visitor.paint.PaintColors;
051import org.openstreetmap.josm.data.preferences.AbstractProperty;
052import org.openstreetmap.josm.data.preferences.BooleanProperty;
053import org.openstreetmap.josm.data.preferences.CachingProperty;
054import org.openstreetmap.josm.data.preferences.DoubleProperty;
055import org.openstreetmap.josm.data.preferences.NamedColorProperty;
056import org.openstreetmap.josm.data.preferences.StrokeProperty;
057import org.openstreetmap.josm.gui.MainApplication;
058import org.openstreetmap.josm.gui.MainMenu;
059import org.openstreetmap.josm.gui.MapFrame;
060import org.openstreetmap.josm.gui.MapView;
061import org.openstreetmap.josm.gui.MapViewState.MapViewPoint;
062import org.openstreetmap.josm.gui.NavigatableComponent;
063import org.openstreetmap.josm.gui.draw.MapPath2D;
064import org.openstreetmap.josm.gui.layer.Layer;
065import org.openstreetmap.josm.gui.layer.MapViewPaintable;
066import org.openstreetmap.josm.gui.layer.OsmDataLayer;
067import org.openstreetmap.josm.gui.util.KeyPressReleaseListener;
068import org.openstreetmap.josm.gui.util.ModifierExListener;
069import org.openstreetmap.josm.tools.Geometry;
070import org.openstreetmap.josm.tools.ImageProvider;
071import org.openstreetmap.josm.tools.Pair;
072import org.openstreetmap.josm.tools.Shortcut;
073import org.openstreetmap.josm.tools.Utils;
074
075/**
076 * Mapmode to add nodes, create and extend ways.
077 */
078public class DrawAction extends MapMode implements MapViewPaintable, DataSelectionListener, KeyPressReleaseListener, ModifierExListener {
079
080    /**
081     * If this property is set, the draw action moves the viewport when adding new points.
082     * @since 12182
083     */
084    public static final CachingProperty<Boolean> VIEWPORT_FOLLOWING = new BooleanProperty("draw.viewport.following", false).cached();
085
086    private static final Color ORANGE_TRANSPARENT = new Color(Color.ORANGE.getRed(), Color.ORANGE.getGreen(), Color.ORANGE.getBlue(), 128);
087
088    private static final ArrowPaintHelper START_WAY_INDICATOR = new ArrowPaintHelper(Utils.toRadians(90), 8);
089
090    static final CachingProperty<Boolean> USE_REPEATED_SHORTCUT
091            = new BooleanProperty("draw.anglesnap.toggleOnRepeatedA", true).cached();
092    static final CachingProperty<BasicStroke> RUBBER_LINE_STROKE
093            = new StrokeProperty("draw.stroke.helper-line", "3").cached();
094
095    static final CachingProperty<BasicStroke> HIGHLIGHT_STROKE
096            = new StrokeProperty("draw.anglesnap.stroke.highlight", "10").cached();
097    static final CachingProperty<BasicStroke> HELPER_STROKE
098            = new StrokeProperty("draw.anglesnap.stroke.helper", "1 4").cached();
099
100    static final CachingProperty<Double> SNAP_ANGLE_TOLERANCE
101            = new DoubleProperty("draw.anglesnap.tolerance", 5.0).cached();
102    static final CachingProperty<Boolean> DRAW_CONSTRUCTION_GEOMETRY
103            = new BooleanProperty("draw.anglesnap.drawConstructionGeometry", true).cached();
104    static final CachingProperty<Boolean> SHOW_PROJECTED_POINT
105            = new BooleanProperty("draw.anglesnap.drawProjectedPoint", true).cached();
106    static final CachingProperty<Boolean> SNAP_TO_PROJECTIONS
107            = new BooleanProperty("draw.anglesnap.projectionsnap", true).cached();
108
109    static final CachingProperty<Boolean> SHOW_ANGLE
110            = new BooleanProperty("draw.anglesnap.showAngle", true).cached();
111
112    static final CachingProperty<Color> SNAP_HELPER_COLOR
113            = new NamedColorProperty(marktr("draw angle snap"), Color.ORANGE).cached();
114
115    static final CachingProperty<Color> HIGHLIGHT_COLOR
116            = new NamedColorProperty(marktr("draw angle snap highlight"), ORANGE_TRANSPARENT).cached();
117
118    static final AbstractProperty<Color> RUBBER_LINE_COLOR
119            = PaintColors.SELECTED.getProperty().getChildColor(marktr("helper line"));
120
121    static final CachingProperty<Boolean> DRAW_HELPER_LINE
122            = new BooleanProperty("draw.helper-line", true).cached();
123    static final CachingProperty<Boolean> DRAW_TARGET_HIGHLIGHT
124            = new BooleanProperty("draw.target-highlight", true).cached();
125    static final CachingProperty<Double> SNAP_TO_INTERSECTION_THRESHOLD
126            = new DoubleProperty("edit.snap-intersection-threshold", 10).cached();
127
128    private final Cursor cursorJoinNode;
129    private final Cursor cursorJoinWay;
130
131    private transient Node lastUsedNode;
132    private double toleranceMultiplier;
133
134    private transient Node mouseOnExistingNode;
135    private transient Set<Way> mouseOnExistingWays = new HashSet<>();
136    // old highlights store which primitives are currently highlighted. This
137    // is true, even if target highlighting is disabled since the status bar
138    // derives its information from this list as well.
139    private transient Set<OsmPrimitive> oldHighlights = new HashSet<>();
140    // new highlights contains a list of primitives that should be highlighted
141    // but haven't been so far. The idea is to compare old and new and only
142    // repaint if there are changes.
143    private transient Set<OsmPrimitive> newHighlights = new HashSet<>();
144    private boolean wayIsFinished;
145    private Point mousePos;
146    private Point oldMousePos;
147
148    private transient Node currentBaseNode;
149    private transient Node previousNode;
150    private EastNorth currentMouseEastNorth;
151
152    private final transient DrawSnapHelper snapHelper = new DrawSnapHelper(this);
153
154    private final transient Shortcut backspaceShortcut;
155    private final BackSpaceAction backspaceAction;
156    private final transient Shortcut snappingShortcut;
157    private boolean ignoreNextKeyRelease;
158
159    private final SnapChangeAction snapChangeAction;
160    private final JCheckBoxMenuItem snapCheckboxMenuItem;
161    private static final BasicStroke BASIC_STROKE = new BasicStroke(1);
162
163    private Point rightClickPressPos;
164
165    /**
166     * Constructs a new {@code DrawAction}.
167     * @since 11713
168     */
169    public DrawAction() {
170        super(tr("Draw"), "node/autonode", tr("Draw nodes"),
171                Shortcut.registerShortcut("mapmode:draw", tr("Mode: {0}", tr("Draw")), KeyEvent.VK_A, Shortcut.DIRECT),
172                ImageProvider.getCursor("crosshair", null));
173
174        snappingShortcut = Shortcut.registerShortcut("mapmode:drawanglesnapping",
175                tr("Mode: Draw Angle snapping"), KeyEvent.CHAR_UNDEFINED, Shortcut.NONE);
176        snapChangeAction = new SnapChangeAction();
177        snapCheckboxMenuItem = addMenuItem();
178        snapHelper.setMenuCheckBox(snapCheckboxMenuItem);
179        backspaceShortcut = Shortcut.registerShortcut("mapmode:backspace",
180                tr("Backspace in Add mode"), KeyEvent.VK_BACK_SPACE, Shortcut.DIRECT);
181        backspaceAction = new BackSpaceAction();
182        cursorJoinNode = ImageProvider.getCursor("crosshair", "joinnode");
183        cursorJoinWay = ImageProvider.getCursor("crosshair", "joinway");
184
185        snapHelper.init();
186    }
187
188    private JCheckBoxMenuItem addMenuItem() {
189        int n = MainApplication.getMenu().editMenu.getItemCount();
190        for (int i = n-1; i > 0; i--) {
191            JMenuItem item = MainApplication.getMenu().editMenu.getItem(i);
192            if (item != null && item.getAction() != null && item.getAction() instanceof SnapChangeAction) {
193                MainApplication.getMenu().editMenu.remove(i);
194            }
195        }
196        return MainMenu.addWithCheckbox(MainApplication.getMenu().editMenu, snapChangeAction, MainMenu.WINDOW_MENU_GROUP.VOLATILE);
197    }
198
199    /**
200     * Checks if a map redraw is required and does so if needed. Also updates the status bar.
201     * @param e event, can be null
202     * @return true if a repaint is needed
203     */
204    private boolean redrawIfRequired(Object e) {
205        updateStatusLine();
206        // repaint required if the helper line is active.
207        boolean needsRepaint = DRAW_HELPER_LINE.get() && !wayIsFinished;
208        if (DRAW_TARGET_HIGHLIGHT.get()) {
209            // move newHighlights to oldHighlights; only update changed primitives
210            for (OsmPrimitive x : newHighlights) {
211                if (oldHighlights.contains(x)) {
212                    continue;
213                }
214                x.setHighlighted(true);
215                needsRepaint = true;
216            }
217            oldHighlights.removeAll(newHighlights);
218            for (OsmPrimitive x : oldHighlights) {
219                x.setHighlighted(false);
220                needsRepaint = true;
221            }
222        }
223        // required in order to print correct help text
224        oldHighlights = newHighlights;
225
226        if (!needsRepaint && !DRAW_TARGET_HIGHLIGHT.get())
227            return false;
228
229        // update selection to reflect which way being modified
230        OsmDataLayer editLayer = getLayerManager().getEditLayer();
231        Node baseNode = getCurrentBaseNode();
232        if (editLayer != null && baseNode != null && !editLayer.data.selectionEmpty()) {
233            DataSet currentDataSet = editLayer.data;
234            Way continueFrom = getWayForNode(baseNode);
235            if (alt && continueFrom != null && (!baseNode.isSelected() || continueFrom.isSelected())) {
236                addRemoveSelection(currentDataSet, baseNode, continueFrom);
237                needsRepaint = true;
238            } else if (!alt && continueFrom != null && !continueFrom.isSelected()) {
239                addSelection(currentDataSet, continueFrom);
240                needsRepaint = true;
241            }
242        }
243
244        if (!needsRepaint && e instanceof SelectionChangeEvent) {
245            SelectionChangeEvent event = (SelectionChangeEvent) e;
246            needsRepaint = !event.getOldSelection().isEmpty() && event.getSelection().isEmpty();
247        }
248
249        if (needsRepaint && editLayer != null) {
250            editLayer.invalidate();
251        }
252        return needsRepaint;
253    }
254
255    private static void addRemoveSelection(DataSet ds, OsmPrimitive toAdd, OsmPrimitive toRemove) {
256        ds.beginUpdate(); // to prevent the selection listener to screw around with the state
257        try {
258            addSelection(ds, toAdd);
259            clearSelection(ds, toRemove);
260        } finally {
261            ds.endUpdate();
262        }
263    }
264
265    private static void updatePreservedFlag(OsmPrimitive osm, boolean state) {
266        // Preserves selected primitives and selected way nodes
267        osm.setPreserved(state);
268        if (osm instanceof Way) {
269            for (Node n : ((Way) osm).getNodes()) {
270                n.setPreserved(state);
271            }
272        }
273    }
274
275    private static void setSelection(DataSet ds, Collection<OsmPrimitive> toSet) {
276        toSet.stream().forEach(x -> updatePreservedFlag(x, true));
277        ds.setSelected(toSet);
278    }
279
280    private static void setSelection(DataSet ds, OsmPrimitive toSet) {
281        updatePreservedFlag(toSet, true);
282        ds.setSelected(toSet);
283    }
284
285    private static void addSelection(DataSet ds, OsmPrimitive toAdd) {
286        updatePreservedFlag(toAdd, true);
287        ds.addSelected(toAdd);
288    }
289
290    private static void clearSelection(DataSet ds, OsmPrimitive toRemove) {
291        ds.clearSelection(toRemove);
292        updatePreservedFlag(toRemove, false);
293    }
294
295    @Override
296    public void enterMode() {
297        if (!isEnabled())
298            return;
299        super.enterMode();
300        readPreferences();
301
302        // determine if selection is suitable to continue drawing. If it
303        // isn't, set wayIsFinished to true to avoid superfluous repaints.
304        determineCurrentBaseNodeAndPreviousNode(getLayerManager().getEditDataSet().getSelected());
305        wayIsFinished = getCurrentBaseNode() == null;
306
307        toleranceMultiplier = 0.01 * NavigatableComponent.PROP_SNAP_DISTANCE.get();
308
309        snapHelper.init();
310        snapCheckboxMenuItem.getAction().setEnabled(true);
311
312        MapFrame map = MainApplication.getMap();
313        map.statusLine.getAnglePanel().addMouseListener(snapHelper.anglePopupListener);
314        MainApplication.registerActionShortcut(backspaceAction, backspaceShortcut);
315
316        map.mapView.addMouseListener(this);
317        map.mapView.addMouseMotionListener(this);
318        map.mapView.addTemporaryLayer(this);
319        SelectionEventManager.getInstance().addSelectionListenerForEdt(this);
320
321        map.keyDetector.addKeyListener(this);
322        map.keyDetector.addModifierExListener(this);
323        ignoreNextKeyRelease = true;
324    }
325
326    @Override
327    public void exitMode() {
328        super.exitMode();
329        MapFrame map = MainApplication.getMap();
330        map.mapView.removeMouseListener(this);
331        map.mapView.removeMouseMotionListener(this);
332        map.mapView.removeTemporaryLayer(this);
333        SelectionEventManager.getInstance().removeSelectionListener(this);
334        MainApplication.unregisterActionShortcut(backspaceAction, backspaceShortcut);
335        snapHelper.unsetFixedMode();
336        snapCheckboxMenuItem.getAction().setEnabled(false);
337
338        map.statusLine.getAnglePanel().removeMouseListener(snapHelper.anglePopupListener);
339        map.statusLine.activateAnglePanel(false);
340
341        DataSet ds = getLayerManager().getEditDataSet();
342        if (ds != null) {
343            ds.getSelected().stream().forEach(x -> updatePreservedFlag(x, false));
344        }
345
346        removeHighlighting(null);
347        map.keyDetector.removeKeyListener(this);
348        map.keyDetector.removeModifierExListener(this);
349    }
350
351    /**
352     * redraw to (possibly) get rid of helper line if selection changes.
353     */
354    @Override
355    public void modifiersExChanged(int modifiers) {
356        if (!MainApplication.isDisplayingMapView() || !MainApplication.getMap().mapView.isActiveLayerDrawable())
357            return;
358        updateKeyModifiersEx(modifiers);
359        computeHelperLine();
360        addHighlighting(null);
361    }
362
363    @Override
364    public void doKeyPressed(KeyEvent e) {
365        if (!snappingShortcut.isEvent(e) && !(USE_REPEATED_SHORTCUT.get() && getShortcut().isEvent(e)))
366            return;
367        snapHelper.setFixedMode();
368        computeHelperLine();
369        redrawIfRequired(e);
370    }
371
372    @Override
373    public void doKeyReleased(KeyEvent e) {
374        if (!snappingShortcut.isEvent(e) && !(USE_REPEATED_SHORTCUT.get() && getShortcut().isEvent(e)))
375            return;
376        if (ignoreNextKeyRelease) {
377            ignoreNextKeyRelease = false;
378            return;
379        }
380        snapHelper.unFixOrTurnOff();
381        computeHelperLine();
382        redrawIfRequired(e);
383    }
384
385    /**
386     * redraw to (possibly) get rid of helper line if selection changes.
387     */
388    @Override
389    public void selectionChanged(SelectionChangeEvent event) {
390        if (!MainApplication.getMap().mapView.isActiveLayerDrawable())
391            return;
392        // Make sure helper line is computed later (causes deadlock in selection event chain otherwise)
393        SwingUtilities.invokeLater(() -> {
394            event.getOldSelection().stream().forEach(x -> updatePreservedFlag(x, false));
395            event.getSelection().stream().forEach(x -> updatePreservedFlag(x, true));
396            if (MainApplication.getMap() != null) {
397                computeHelperLine();
398                addHighlighting(event);
399            }
400        });
401    }
402
403    private void tryAgain(MouseEvent e) {
404        getLayerManager().getEditDataSet().clearSelection();
405        mouseReleased(e);
406    }
407
408    /**
409     * This function should be called when the user wishes to finish his current draw action.
410     * If Potlatch Style is enabled, it will switch to select tool, otherwise simply disable
411     * the helper line until the user chooses to draw something else.
412     */
413    private void finishDrawing() {
414        lastUsedNode = null;
415        wayIsFinished = true;
416        MainApplication.getMap().selectSelectTool(true);
417        snapHelper.noSnapNow();
418
419        // Redraw to remove the helper line stub
420        computeHelperLine();
421        removeHighlighting(null);
422    }
423
424    @Override
425    public void mousePressed(MouseEvent e) {
426        if (e.getButton() == MouseEvent.BUTTON3) {
427            rightClickPressPos = e.getPoint();
428        }
429    }
430
431    /**
432     * If user clicked with the left button, add a node at the current mouse
433     * position.
434     *
435     * If in nodeway mode, insert the node into the way.
436     */
437    @Override
438    public void mouseReleased(MouseEvent e) {
439        if (e.getButton() == MouseEvent.BUTTON3) {
440            Point curMousePos = e.getPoint();
441            if (curMousePos.equals(rightClickPressPos)) {
442                tryToSetBaseSegmentForAngleSnap();
443            }
444            return;
445        }
446        if (e.getButton() != MouseEvent.BUTTON1)
447            return;
448        MapView mapView = MainApplication.getMap().mapView;
449        if (!mapView.isActiveLayerDrawable())
450            return;
451        // request focus in order to enable the expected keyboard shortcuts
452        //
453        mapView.requestFocus();
454
455        if (e.getClickCount() > 1 && mousePos != null && mousePos.equals(oldMousePos)) {
456            // A double click equals "user clicked last node again, finish way"
457            // Change draw tool only if mouse position is nearly the same, as
458            // otherwise fast clicks will count as a double click
459            finishDrawing();
460            return;
461        }
462        oldMousePos = mousePos;
463
464        // we copy ctrl/alt/shift from the event just in case our global
465        // keyDetector didn't make it through the security manager. Unclear
466        // if that can ever happen but better be safe.
467        updateKeyModifiers(e);
468        mousePos = e.getPoint();
469
470        DataSet ds = getLayerManager().getEditDataSet();
471        Collection<OsmPrimitive> selection = new ArrayList<>(ds.getSelected());
472
473        boolean newNode = false;
474        Node n = mapView.getNearestNode(mousePos, OsmPrimitive::isSelectable);
475        if (ctrl) {
476            Iterator<Way> it = ds.getSelectedWays().iterator();
477            if (it.hasNext()) {
478                // ctrl-click on node of selected way = reuse node despite of ctrl
479                if (!it.next().containsNode(n)) n = null;
480            } else {
481                n = null; // ctrl-click + no selected way = new node
482            }
483        }
484
485        if (n != null && !snapHelper.isActive()) {
486            // user clicked on node
487            if (selection.isEmpty() || wayIsFinished) {
488                // select the clicked node and do nothing else
489                // (this is just a convenience option so that people don't
490                // have to switch modes)
491
492                setSelection(ds, n);
493                // If we extend/continue an existing way, select it already now to make it obvious
494                Way continueFrom = getWayForNode(n);
495                if (continueFrom != null) {
496                    addSelection(ds, continueFrom);
497                }
498
499                // The user explicitly selected a node, so let him continue drawing
500                wayIsFinished = false;
501                return;
502            }
503        } else {
504            EastNorth newEN;
505            if (n != null) {
506                EastNorth foundPoint = n.getEastNorth();
507                // project found node to snapping line
508                newEN = snapHelper.getSnapPoint(foundPoint);
509                // do not add new node if there is some node within snapping distance
510                double tolerance = mapView.getDist100Pixel() * toleranceMultiplier;
511                if (foundPoint.distance(newEN) > tolerance) {
512                    n = new Node(newEN); // point != projected, so we create new node
513                    newNode = true;
514                }
515            } else { // n==null, no node found in clicked area
516                EastNorth mouseEN = mapView.getEastNorth(e.getX(), e.getY());
517                newEN = snapHelper.isSnapOn() ? snapHelper.getSnapPoint(mouseEN) : mouseEN;
518                n = new Node(newEN); //create node at clicked point
519                newNode = true;
520            }
521            snapHelper.unsetFixedMode();
522        }
523
524        Collection<Command> cmds = new LinkedList<>();
525        Collection<OsmPrimitive> newSelection = new LinkedList<>(ds.getSelected());
526        List<Way> reuseWays = new ArrayList<>();
527        List<Way> replacedWays = new ArrayList<>();
528
529        if (newNode) {
530            if (n.getCoor().isOutSideWorld()) {
531                JOptionPane.showMessageDialog(
532                        Main.parent,
533                        tr("Cannot add a node outside of the world."),
534                        tr("Warning"),
535                        JOptionPane.WARNING_MESSAGE
536                        );
537                return;
538            }
539            cmds.add(new AddCommand(ds, n));
540
541            if (!ctrl) {
542                // Insert the node into all the nearby way segments
543                List<WaySegment> wss = mapView.getNearestWaySegments(
544                        mapView.getPoint(n), OsmPrimitive::isSelectable);
545                if (snapHelper.isActive()) {
546                    tryToMoveNodeOnIntersection(wss, n);
547                }
548                insertNodeIntoAllNearbySegments(wss, n, newSelection, cmds, replacedWays, reuseWays);
549            }
550        }
551        // now "n" is newly created or reused node that shoud be added to some way
552
553        // This part decides whether or not a "segment" (i.e. a connection) is made to an existing node.
554
555        // For a connection to be made, the user must either have a node selected (connection
556        // is made to that node), or he must have a way selected *and* one of the endpoints
557        // of that way must be the last used node (connection is made to last used node), or
558        // he must have a way and a node selected (connection is made to the selected node).
559
560        // If the above does not apply, the selection is cleared and a new try is started
561
562        boolean extendedWay = false;
563        boolean wayIsFinishedTemp = wayIsFinished;
564        wayIsFinished = false;
565
566        // don't draw lines if shift is held
567        if (!selection.isEmpty() && !shift) {
568            Node selectedNode = null;
569            Way selectedWay = null;
570
571            for (OsmPrimitive p : selection) {
572                if (p instanceof Node) {
573                    if (selectedNode != null) {
574                        // Too many nodes selected to do something useful
575                        tryAgain(e);
576                        return;
577                    }
578                    selectedNode = (Node) p;
579                } else if (p instanceof Way) {
580                    if (selectedWay != null) {
581                        // Too many ways selected to do something useful
582                        tryAgain(e);
583                        return;
584                    }
585                    selectedWay = (Way) p;
586                }
587            }
588
589            // the node from which we make a connection
590            Node n0 = findNodeToContinueFrom(selectedNode, selectedWay);
591            // We have a selection but it isn't suitable. Try again.
592            if (n0 == null) {
593                tryAgain(e);
594                return;
595            }
596            if (!wayIsFinishedTemp) {
597                if (isSelfContainedWay(selectedWay, n0, n))
598                    return;
599
600                // User clicked last node again, finish way
601                if (n0 == n) {
602                    finishDrawing();
603                    return;
604                }
605
606                // Ok we know now that we'll insert a line segment, but will it connect to an
607                // existing way or make a new way of its own? The "alt" modifier means that the
608                // user wants a new way.
609                Way way = alt ? null : (selectedWay != null ? selectedWay : getWayForNode(n0));
610                Way wayToSelect;
611
612                // Don't allow creation of self-overlapping ways
613                if (way != null) {
614                    int nodeCount = 0;
615                    for (Node p : way.getNodes()) {
616                        if (p.equals(n0)) {
617                            nodeCount++;
618                        }
619                    }
620                    if (nodeCount > 1) {
621                        way = null;
622                    }
623                }
624
625                if (way == null) {
626                    way = new Way();
627                    way.addNode(n0);
628                    cmds.add(new AddCommand(ds, way));
629                    wayToSelect = way;
630                } else {
631                    int i;
632                    if ((i = replacedWays.indexOf(way)) != -1) {
633                        way = reuseWays.get(i);
634                        wayToSelect = way;
635                    } else {
636                        wayToSelect = way;
637                        Way wnew = new Way(way);
638                        cmds.add(new ChangeCommand(way, wnew));
639                        way = wnew;
640                    }
641                }
642
643                // Connected to a node that's already in the way
644                if (way.containsNode(n)) {
645                    wayIsFinished = true;
646                    selection.clear();
647                }
648
649                // Add new node to way
650                if (way.getNode(way.getNodesCount() - 1) == n0) {
651                    way.addNode(n);
652                } else {
653                    way.addNode(0, n);
654                }
655
656                extendedWay = true;
657                newSelection.clear();
658                newSelection.add(wayToSelect);
659            }
660        }
661        if (!extendedWay && !newNode) {
662            return; // We didn't do anything.
663        }
664
665        String title = getTitle(newNode, n, newSelection, reuseWays, extendedWay);
666
667        Command c = new SequenceCommand(title, cmds);
668
669        MainApplication.undoRedo.add(c);
670        if (!wayIsFinished) {
671            lastUsedNode = n;
672        }
673
674        setSelection(ds, newSelection);
675
676        // "viewport following" mode for tracing long features
677        // from aerial imagery or GPS tracks.
678        if (VIEWPORT_FOLLOWING.get()) {
679            mapView.smoothScrollTo(n.getEastNorth());
680        }
681        computeHelperLine();
682        removeHighlighting(e);
683    }
684
685    private static String getTitle(boolean newNode, Node n, Collection<OsmPrimitive> newSelection, List<Way> reuseWays,
686            boolean extendedWay) {
687        String title;
688        if (!extendedWay) {
689            if (reuseWays.isEmpty()) {
690                title = tr("Add node");
691            } else {
692                title = tr("Add node into way");
693                for (Way w : reuseWays) {
694                    newSelection.remove(w);
695                }
696            }
697            newSelection.clear();
698            newSelection.add(n);
699        } else if (!newNode) {
700            title = tr("Connect existing way to node");
701        } else if (reuseWays.isEmpty()) {
702            title = tr("Add a new node to an existing way");
703        } else {
704            title = tr("Add node into way and connect");
705        }
706        return title;
707    }
708
709    private void insertNodeIntoAllNearbySegments(List<WaySegment> wss, Node n, Collection<OsmPrimitive> newSelection,
710            Collection<Command> cmds, List<Way> replacedWays, List<Way> reuseWays) {
711        Map<Way, List<Integer>> insertPoints = new HashMap<>();
712        for (WaySegment ws : wss) {
713            List<Integer> is;
714            if (insertPoints.containsKey(ws.way)) {
715                is = insertPoints.get(ws.way);
716            } else {
717                is = new ArrayList<>();
718                insertPoints.put(ws.way, is);
719            }
720
721            is.add(ws.lowerIndex);
722        }
723
724        Set<Pair<Node, Node>> segSet = new HashSet<>();
725
726        for (Map.Entry<Way, List<Integer>> insertPoint : insertPoints.entrySet()) {
727            Way w = insertPoint.getKey();
728            List<Integer> is = insertPoint.getValue();
729
730            Way wnew = new Way(w);
731
732            pruneSuccsAndReverse(is);
733            for (int i : is) {
734                segSet.add(Pair.sort(new Pair<>(w.getNode(i), w.getNode(i+1))));
735                wnew.addNode(i + 1, n);
736            }
737
738            // If ALT is pressed, a new way should be created and that new way should get
739            // selected. This works everytime unless the ways the nodes get inserted into
740            // are already selected. This is the case when creating a self-overlapping way
741            // but pressing ALT prevents this. Therefore we must de-select the way manually
742            // here so /only/ the new way will be selected after this method finishes.
743            if (alt) {
744                newSelection.add(insertPoint.getKey());
745            }
746
747            cmds.add(new ChangeCommand(insertPoint.getKey(), wnew));
748            replacedWays.add(insertPoint.getKey());
749            reuseWays.add(wnew);
750        }
751
752        adjustNode(segSet, n);
753    }
754
755    /**
756     * Prevent creation of ways that look like this: &lt;----&gt;
757     * This happens if users want to draw a no-exit-sideway from the main way like this:
758     * ^
759     * |&lt;----&gt;
760     * |
761     * The solution isn't ideal because the main way will end in the side way, which is bad for
762     * navigation software ("drive straight on") but at least easier to fix. Maybe users will fix
763     * it on their own, too. At least it's better than producing an error.
764     *
765     * @param selectedWay the way to check
766     * @param currentNode the current node (i.e. the one the connection will be made from)
767     * @param targetNode the target node (i.e. the one the connection will be made to)
768     * @return {@code true} if this would create a selfcontaining way, {@code false} otherwise.
769     */
770    private boolean isSelfContainedWay(Way selectedWay, Node currentNode, Node targetNode) {
771        if (selectedWay != null) {
772            int posn0 = selectedWay.getNodes().indexOf(currentNode);
773            // CHECKSTYLE.OFF: SingleSpaceSeparator
774            if ((posn0 != -1 && // n0 is part of way
775                (posn0 >= 1                            && targetNode.equals(selectedWay.getNode(posn0-1)))) || // previous node
776                (posn0 < selectedWay.getNodesCount()-1 && targetNode.equals(selectedWay.getNode(posn0+1)))) {  // next node
777                setSelection(getLayerManager().getEditDataSet(), targetNode);
778                lastUsedNode = targetNode;
779                return true;
780            }
781            // CHECKSTYLE.ON: SingleSpaceSeparator
782        }
783
784        return false;
785    }
786
787    /**
788     * Finds a node to continue drawing from. Decision is based upon given node and way.
789     * @param selectedNode Currently selected node, may be null
790     * @param selectedWay Currently selected way, may be null
791     * @return Node if a suitable node is found, null otherwise
792     */
793    private Node findNodeToContinueFrom(Node selectedNode, Way selectedWay) {
794        // No nodes or ways have been selected, this occurs when a relation
795        // has been selected or the selection is empty
796        if (selectedNode == null && selectedWay == null)
797            return null;
798
799        if (selectedNode == null) {
800            if (selectedWay.isFirstLastNode(lastUsedNode))
801                return lastUsedNode;
802
803            // We have a way selected, but no suitable node to continue from. Start anew.
804            return null;
805        }
806
807        if (selectedWay == null)
808            return selectedNode;
809
810        if (selectedWay.isFirstLastNode(selectedNode))
811            return selectedNode;
812
813        // We have a way and node selected, but it's not at the start/end of the way. Start anew.
814        return null;
815    }
816
817    @Override
818    public void mouseDragged(MouseEvent e) {
819        mouseMoved(e);
820    }
821
822    @Override
823    public void mouseMoved(MouseEvent e) {
824        if (!MainApplication.getMap().mapView.isActiveLayerDrawable())
825            return;
826
827        // we copy ctrl/alt/shift from the event just in case our global
828        // keyDetector didn't make it through the security manager. Unclear
829        // if that can ever happen but better be safe.
830        updateKeyModifiers(e);
831        mousePos = e.getPoint();
832        if (snapHelper.isSnapOn() && ctrl)
833            tryToSetBaseSegmentForAngleSnap();
834
835        computeHelperLine();
836        addHighlighting(e);
837    }
838
839    /**
840     * This method is used to detect segment under mouse and use it as reference for angle snapping
841     */
842    private void tryToSetBaseSegmentForAngleSnap() {
843        if (mousePos != null) {
844            WaySegment seg = MainApplication.getMap().mapView.getNearestWaySegment(mousePos, OsmPrimitive::isSelectable);
845            if (seg != null) {
846                snapHelper.setBaseSegment(seg);
847            }
848        }
849    }
850
851    /**
852     * This method prepares data required for painting the "helper line" from
853     * the last used position to the mouse cursor. It duplicates some code from
854     * mouseReleased() (FIXME).
855     */
856    private void computeHelperLine() {
857        if (mousePos == null) {
858            // Don't draw the line.
859            currentMouseEastNorth = null;
860            currentBaseNode = null;
861            return;
862        }
863
864        DataSet ds = getLayerManager().getEditDataSet();
865        Collection<OsmPrimitive> selection = ds != null ? ds.getSelected() : Collections.emptyList();
866
867        MapView mv = MainApplication.getMap().mapView;
868        Node currentMouseNode = null;
869        mouseOnExistingNode = null;
870        mouseOnExistingWays = new HashSet<>();
871
872        if (!ctrl && mousePos != null) {
873            currentMouseNode = mv.getNearestNode(mousePos, OsmPrimitive::isSelectable);
874        }
875
876        // We need this for highlighting and we'll only do so if we actually want to re-use
877        // *and* there is no node nearby (because nodes beat ways when re-using)
878        if (!ctrl && currentMouseNode == null) {
879            List<WaySegment> wss = mv.getNearestWaySegments(mousePos, OsmPrimitive::isSelectable);
880            for (WaySegment ws : wss) {
881                mouseOnExistingWays.add(ws.way);
882            }
883        }
884
885        if (currentMouseNode != null) {
886            // user clicked on node
887            if (selection.isEmpty()) return;
888            currentMouseEastNorth = currentMouseNode.getEastNorth();
889            mouseOnExistingNode = currentMouseNode;
890        } else {
891            // no node found in clicked area
892            currentMouseEastNorth = mv.getEastNorth(mousePos.x, mousePos.y);
893        }
894
895        determineCurrentBaseNodeAndPreviousNode(selection);
896        if (previousNode == null) {
897            snapHelper.noSnapNow();
898        }
899
900        if (getCurrentBaseNode() == null || getCurrentBaseNode() == currentMouseNode)
901            return; // Don't create zero length way segments.
902
903        showStatusInfo(-1, -1, -1, snapHelper.isSnapOn());
904
905        double curHdg = Utils.toDegrees(getCurrentBaseNode().getEastNorth()
906                .heading(currentMouseEastNorth));
907        double baseHdg = -1;
908        if (previousNode != null) {
909            EastNorth en = previousNode.getEastNorth();
910            if (en != null) {
911                baseHdg = Utils.toDegrees(en.heading(getCurrentBaseNode().getEastNorth()));
912            }
913        }
914
915        snapHelper.checkAngleSnapping(currentMouseEastNorth, baseHdg, curHdg);
916
917        // status bar was filled by snapHelper
918    }
919
920    static void showStatusInfo(double angle, double hdg, double distance, boolean activeFlag) {
921        MapFrame map = MainApplication.getMap();
922        map.statusLine.setAngle(angle);
923        map.statusLine.activateAnglePanel(activeFlag);
924        map.statusLine.setHeading(hdg);
925        map.statusLine.setDist(distance);
926    }
927
928    /**
929     * Helper function that sets fields currentBaseNode and previousNode
930     * @param selection
931     * uses also lastUsedNode field
932     */
933    private void determineCurrentBaseNodeAndPreviousNode(Collection<OsmPrimitive> selection) {
934        Node selectedNode = null;
935        Way selectedWay = null;
936        for (OsmPrimitive p : selection) {
937            if (p instanceof Node) {
938                if (selectedNode != null)
939                    return;
940                selectedNode = (Node) p;
941            } else if (p instanceof Way) {
942                if (selectedWay != null)
943                    return;
944                selectedWay = (Way) p;
945            }
946        }
947        // we are here, if not more than 1 way or node is selected,
948
949        // the node from which we make a connection
950        currentBaseNode = null;
951        previousNode = null;
952
953        // Try to find an open way to measure angle from it. The way is not to be continued!
954        // warning: may result in changes of currentBaseNode and previousNode
955        // please remove if bugs arise
956        if (selectedWay == null && selectedNode != null) {
957            for (OsmPrimitive p: selectedNode.getReferrers()) {
958                if (p.isUsable() && p instanceof Way && ((Way) p).isFirstLastNode(selectedNode)) {
959                    if (selectedWay != null) { // two uncontinued ways, nothing to take as reference
960                        selectedWay = null;
961                        break;
962                    } else {
963                        // set us ~continue this way (measure angle from it)
964                        selectedWay = (Way) p;
965                    }
966                }
967            }
968        }
969
970        if (selectedNode == null) {
971            if (selectedWay == null)
972                return;
973            continueWayFromNode(selectedWay, lastUsedNode);
974        } else if (selectedWay == null) {
975            currentBaseNode = selectedNode;
976        } else if (!selectedWay.isDeleted()) { // fix #7118
977            continueWayFromNode(selectedWay, selectedNode);
978        }
979    }
980
981    /**
982     * if one of the ends of {@code way} is given {@code node},
983     * then set currentBaseNode = node and previousNode = adjacent node of way
984     * @param way way to continue
985     * @param node starting node
986     */
987    private void continueWayFromNode(Way way, Node node) {
988        int n = way.getNodesCount();
989        if (node == way.firstNode()) {
990            currentBaseNode = node;
991            if (n > 1) previousNode = way.getNode(1);
992        } else if (node == way.lastNode()) {
993            currentBaseNode = node;
994            if (n > 1) previousNode = way.getNode(n-2);
995        }
996    }
997
998    /**
999     * Repaint on mouse exit so that the helper line goes away.
1000     */
1001    @Override
1002    public void mouseExited(MouseEvent e) {
1003        OsmDataLayer editLayer = MainApplication.getLayerManager().getEditLayer();
1004        if (editLayer == null)
1005            return;
1006        mousePos = e.getPoint();
1007        snapHelper.noSnapNow();
1008        boolean repaintIssued = removeHighlighting(e);
1009        // force repaint in case snapHelper needs one. If removeHighlighting
1010        // caused one already, don't do it again.
1011        if (!repaintIssued) {
1012            editLayer.invalidate();
1013        }
1014    }
1015
1016    /**
1017     * Replies the parent way of a node, if it is the end of exactly one usable way.
1018     * @param n node
1019     * @return If the node is the end of exactly one way, return this.
1020     *  <code>null</code> otherwise.
1021     */
1022    public static Way getWayForNode(Node n) {
1023        Way way = null;
1024        for (Way w : Utils.filteredCollection(n.getReferrers(), Way.class)) {
1025            if (!w.isUsable() || w.getNodesCount() < 1) {
1026                continue;
1027            }
1028            Node firstNode = w.getNode(0);
1029            Node lastNode = w.getNode(w.getNodesCount() - 1);
1030            if ((firstNode == n || lastNode == n) && (firstNode != lastNode)) {
1031                if (way != null)
1032                    return null;
1033                way = w;
1034            }
1035        }
1036        return way;
1037    }
1038
1039    /**
1040     * Replies the current base node, after having checked it is still usable (see #11105).
1041     * @return the current base node (can be null). If not-null, it's guaranteed the node is usable
1042     */
1043    public Node getCurrentBaseNode() {
1044        if (currentBaseNode != null && (currentBaseNode.getDataSet() == null || !currentBaseNode.isUsable())) {
1045            currentBaseNode = null;
1046        }
1047        return currentBaseNode;
1048    }
1049
1050    private static void pruneSuccsAndReverse(List<Integer> is) {
1051        Set<Integer> is2 = new HashSet<>();
1052        for (int i : is) {
1053            if (!is2.contains(i - 1) && !is2.contains(i + 1)) {
1054                is2.add(i);
1055            }
1056        }
1057        is.clear();
1058        is.addAll(is2);
1059        Collections.sort(is);
1060        Collections.reverse(is);
1061    }
1062
1063    /**
1064     * Adjusts the position of a node to lie on a segment (or a segment intersection).
1065     *
1066     * If one or more than two segments are passed, the node is adjusted
1067     * to lie on the first segment that is passed.
1068     *
1069     * If two segments are passed, the node is adjusted to be at their intersection.
1070     *
1071     * No action is taken if no segments are passed.
1072     *
1073     * @param segs the segments to use as a reference when adjusting
1074     * @param n the node to adjust
1075     */
1076    private static void adjustNode(Collection<Pair<Node, Node>> segs, Node n) {
1077        switch (segs.size()) {
1078        case 0:
1079            return;
1080        case 2:
1081            adjustNodeTwoSegments(segs, n);
1082            break;
1083        default:
1084            adjustNodeDefault(segs, n);
1085        }
1086    }
1087
1088    private static void adjustNodeTwoSegments(Collection<Pair<Node, Node>> segs, Node n) {
1089        // This computes the intersection between the two segments and adjusts the node position.
1090        Iterator<Pair<Node, Node>> i = segs.iterator();
1091        Pair<Node, Node> seg = i.next();
1092        EastNorth pA = seg.a.getEastNorth();
1093        EastNorth pB = seg.b.getEastNorth();
1094        seg = i.next();
1095        EastNorth pC = seg.a.getEastNorth();
1096        EastNorth pD = seg.b.getEastNorth();
1097
1098        double u = det(pB.east() - pA.east(), pB.north() - pA.north(), pC.east() - pD.east(), pC.north() - pD.north());
1099
1100        // Check for parallel segments and do nothing if they are
1101        // In practice this will probably only happen when a way has been duplicated
1102
1103        if (u == 0)
1104            return;
1105
1106        // q is a number between 0 and 1
1107        // It is the point in the segment where the intersection occurs
1108        // if the segment is scaled to length 1
1109
1110        double q = det(pB.north() - pC.north(), pB.east() - pC.east(), pD.north() - pC.north(), pD.east() - pC.east()) / u;
1111        EastNorth intersection = new EastNorth(
1112                pB.east() + q * (pA.east() - pB.east()),
1113                pB.north() + q * (pA.north() - pB.north()));
1114
1115
1116        // only adjust to intersection if within snapToIntersectionThreshold pixel of mouse click; otherwise
1117        // fall through to default action.
1118        // (for semi-parallel lines, intersection might be miles away!)
1119        MapFrame map = MainApplication.getMap();
1120        if (map.mapView.getPoint2D(n).distance(map.mapView.getPoint2D(intersection)) < SNAP_TO_INTERSECTION_THRESHOLD.get()) {
1121            n.setEastNorth(intersection);
1122            return;
1123        }
1124
1125        adjustNodeDefault(segs, n);
1126    }
1127
1128    private static void adjustNodeDefault(Collection<Pair<Node, Node>> segs, Node n) {
1129        EastNorth p = n.getEastNorth();
1130        Pair<Node, Node> seg = segs.iterator().next();
1131        EastNorth pA = seg.a.getEastNorth();
1132        EastNorth pB = seg.b.getEastNorth();
1133        double a = p.distanceSq(pB);
1134        double b = p.distanceSq(pA);
1135        double c = pA.distanceSq(pB);
1136        double q = (a - b + c) / (2*c);
1137        n.setEastNorth(new EastNorth(pB.east() + q * (pA.east() - pB.east()), pB.north() + q * (pA.north() - pB.north())));
1138    }
1139
1140    // helper for adjustNode
1141    static double det(double a, double b, double c, double d) {
1142        return a * d - b * c;
1143    }
1144
1145    private void tryToMoveNodeOnIntersection(List<WaySegment> wss, Node n) {
1146        if (wss.isEmpty())
1147            return;
1148        WaySegment ws = wss.get(0);
1149        EastNorth p1 = ws.getFirstNode().getEastNorth();
1150        EastNorth p2 = ws.getSecondNode().getEastNorth();
1151        if (snapHelper.dir2 != null && getCurrentBaseNode() != null) {
1152            EastNorth xPoint = Geometry.getSegmentSegmentIntersection(p1, p2, snapHelper.dir2,
1153                    getCurrentBaseNode().getEastNorth());
1154            if (xPoint != null) {
1155                n.setEastNorth(xPoint);
1156            }
1157        }
1158    }
1159
1160    /**
1161     * Takes the data from computeHelperLine to determine which ways/nodes should be highlighted
1162     * (if feature enabled). Also sets the target cursor if appropriate. It adds the to-be-
1163     * highlighted primitives to newHighlights but does not actually highlight them. This work is
1164     * done in redrawIfRequired. This means, calling addHighlighting() without redrawIfRequired()
1165     * will leave the data in an inconsistent state.
1166     *
1167     * The status bar derives its information from oldHighlights, so in order to update the status
1168     * bar both addHighlighting() and repaintIfRequired() are needed, since former fills newHighlights
1169     * and latter processes them into oldHighlights.
1170     * @param event event, can be null
1171     */
1172    private void addHighlighting(Object event) {
1173        newHighlights = new HashSet<>();
1174        MapView mapView = MainApplication.getMap().mapView;
1175
1176        // if ctrl key is held ("no join"), don't highlight anything
1177        if (ctrl) {
1178            mapView.setNewCursor(cursor, this);
1179            redrawIfRequired(event);
1180            return;
1181        }
1182
1183        // This happens when nothing is selected, but we still want to highlight the "target node"
1184        if (mouseOnExistingNode == null && mousePos != null && getLayerManager().getEditDataSet().selectionEmpty()) {
1185            mouseOnExistingNode = mapView.getNearestNode(mousePos, OsmPrimitive::isSelectable);
1186        }
1187
1188        if (mouseOnExistingNode != null) {
1189            mapView.setNewCursor(cursorJoinNode, this);
1190            newHighlights.add(mouseOnExistingNode);
1191            redrawIfRequired(event);
1192            return;
1193        }
1194
1195        // Insert the node into all the nearby way segments
1196        if (mouseOnExistingWays.isEmpty()) {
1197            mapView.setNewCursor(cursor, this);
1198            redrawIfRequired(event);
1199            return;
1200        }
1201
1202        mapView.setNewCursor(cursorJoinWay, this);
1203        newHighlights.addAll(mouseOnExistingWays);
1204        redrawIfRequired(event);
1205    }
1206
1207    /**
1208     * Removes target highlighting from primitives. Issues repaint if required.
1209     * @param event event, can be null
1210     * @return true if a repaint has been issued.
1211     */
1212    private boolean removeHighlighting(Object event) {
1213        newHighlights = new HashSet<>();
1214        return redrawIfRequired(event);
1215    }
1216
1217    @Override
1218    public void paint(Graphics2D g, MapView mv, Bounds box) {
1219        // sanity checks
1220        MapView mapView = MainApplication.getMap().mapView;
1221        if (mapView == null || mousePos == null
1222                // don't draw line if we don't know where from or where to
1223                || currentMouseEastNorth == null || getCurrentBaseNode() == null
1224                // don't draw line if mouse is outside window
1225                || !mapView.getState().getForView(mousePos.getX(), mousePos.getY()).isInView())
1226            return;
1227
1228        Graphics2D g2 = g;
1229        snapHelper.drawIfNeeded(g2, mv.getState());
1230        if (!DRAW_HELPER_LINE.get() || wayIsFinished || shift)
1231            return;
1232
1233        if (!snapHelper.isActive()) {
1234            g2.setColor(RUBBER_LINE_COLOR.get());
1235            g2.setStroke(RUBBER_LINE_STROKE.get());
1236            paintConstructionGeometry(mv, g2);
1237        } else if (DRAW_CONSTRUCTION_GEOMETRY.get()) {
1238            // else use color and stoke from  snapHelper.draw
1239            paintConstructionGeometry(mv, g2);
1240        }
1241    }
1242
1243    private void paintConstructionGeometry(MapView mv, Graphics2D g2) {
1244        MapPath2D b = new MapPath2D();
1245        MapViewPoint p1 = mv.getState().getPointFor(getCurrentBaseNode());
1246        MapViewPoint p2 = mv.getState().getPointFor(currentMouseEastNorth);
1247
1248        b.moveTo(p1);
1249        b.lineTo(p2);
1250
1251        // if alt key is held ("start new way"), draw a little perpendicular line
1252        if (alt) {
1253            START_WAY_INDICATOR.paintArrowAt(b, p1, p2);
1254        }
1255
1256        g2.draw(b);
1257        g2.setStroke(BASIC_STROKE);
1258    }
1259
1260    @Override
1261    public String getModeHelpText() {
1262        StringBuilder rv;
1263        /*
1264         *  No modifiers: all (Connect, Node Re-Use, Auto-Weld)
1265         *  CTRL: disables node re-use, auto-weld
1266         *  Shift: do not make connection
1267         *  ALT: make connection but start new way in doing so
1268         */
1269
1270        /*
1271         * Status line text generation is split into two parts to keep it maintainable.
1272         * First part looks at what will happen to the new node inserted on click and
1273         * the second part will look if a connection is made or not.
1274         *
1275         * Note that this help text is not absolutely accurate as it doesn't catch any special
1276         * cases (e.g. when preventing <---> ways). The only special that it catches is when
1277         * a way is about to be finished.
1278         *
1279         * First check what happens to the new node.
1280         */
1281
1282        // oldHighlights stores the current highlights. If this
1283        // list is empty we can assume that we won't do any joins
1284        if (ctrl || oldHighlights.isEmpty()) {
1285            rv = new StringBuilder(tr("Create new node."));
1286        } else {
1287            // oldHighlights may store a node or way, check if it's a node
1288            OsmPrimitive x = oldHighlights.iterator().next();
1289            if (x instanceof Node) {
1290                rv = new StringBuilder(tr("Select node under cursor."));
1291            } else {
1292                rv = new StringBuilder(trn("Insert new node into way.", "Insert new node into {0} ways.",
1293                        oldHighlights.size(), oldHighlights.size()));
1294            }
1295        }
1296
1297        /*
1298         * Check whether a connection will be made
1299         */
1300        if (!wayIsFinished && getCurrentBaseNode() != null) {
1301            if (alt) {
1302                rv.append(' ').append(tr("Start new way from last node."));
1303            } else {
1304                rv.append(' ').append(tr("Continue way from last node."));
1305            }
1306            if (snapHelper.isSnapOn()) {
1307                rv.append(' ').append(tr("Angle snapping active."));
1308            }
1309        }
1310
1311        Node n = mouseOnExistingNode;
1312        DataSet ds = getLayerManager().getEditDataSet();
1313        /*
1314         * Handle special case: Highlighted node == selected node => finish drawing
1315         */
1316        if (n != null && ds != null && ds.getSelectedNodes().contains(n)) {
1317            if (wayIsFinished) {
1318                rv = new StringBuilder(tr("Select node under cursor."));
1319            } else {
1320                rv = new StringBuilder(tr("Finish drawing."));
1321            }
1322        }
1323
1324        /*
1325         * Handle special case: Self-Overlapping or closing way
1326         */
1327        if (ds != null && !ds.getSelectedWays().isEmpty() && !wayIsFinished && !alt) {
1328            Way w = ds.getSelectedWays().iterator().next();
1329            for (Node m : w.getNodes()) {
1330                if (m.equals(mouseOnExistingNode) || mouseOnExistingWays.contains(w)) {
1331                    rv.append(' ').append(tr("Finish drawing."));
1332                    break;
1333                }
1334            }
1335        }
1336        return rv.toString();
1337    }
1338
1339    /**
1340     * Get selected primitives, while draw action is in progress.
1341     *
1342     * While drawing a way, technically the last node is selected.
1343     * This is inconvenient when the user tries to add/edit tags to the way.
1344     * For this case, this method returns the current way as selection,
1345     * to work around this issue.
1346     * Otherwise the normal selection of the current data layer is returned.
1347     * @return selected primitives, while draw action is in progress
1348     */
1349    public Collection<OsmPrimitive> getInProgressSelection() {
1350        DataSet ds = getLayerManager().getEditDataSet();
1351        if (ds == null) return null;
1352        if (getCurrentBaseNode() != null && !ds.selectionEmpty()) {
1353            Way continueFrom = getWayForNode(getCurrentBaseNode());
1354            if (continueFrom != null)
1355                return Collections.<OsmPrimitive>singleton(continueFrom);
1356        }
1357        return ds.getSelected();
1358    }
1359
1360    /**
1361     * Gets a collection of primitives that should not be hidden by the filter.
1362     * @return The primitives that the filter should not hide.
1363     * @deprecated use {@link org.openstreetmap.josm.data.osm.DataSet#allPreservedPrimitives}
1364     * @since 11993
1365     */
1366    @Override
1367    @Deprecated
1368    public Collection<? extends OsmPrimitive> getPreservedPrimitives() {
1369        DataSet ds = getLayerManager().getEditDataSet();
1370        return ds != null ? ds.allPreservedPrimitives() : Collections.emptySet();
1371    }
1372
1373    @Override
1374    public boolean layerIsSupported(Layer l) {
1375        return isEditableDataLayer(l);
1376    }
1377
1378    @Override
1379    protected void updateEnabledState() {
1380        setEnabled(getLayerManager().getEditLayer() != null);
1381    }
1382
1383    @Override
1384    public void destroy() {
1385        super.destroy();
1386        snapChangeAction.destroy();
1387    }
1388
1389    /**
1390     * Undo the last command. Binded by default to backspace key.
1391     */
1392    public class BackSpaceAction extends AbstractAction {
1393
1394        @Override
1395        public void actionPerformed(ActionEvent e) {
1396            MainApplication.undoRedo.undo();
1397            Command lastCmd = MainApplication.undoRedo.getLastCommand();
1398            if (lastCmd == null) return;
1399            Node n = null;
1400            for (OsmPrimitive p: lastCmd.getParticipatingPrimitives()) {
1401                if (p instanceof Node) {
1402                    if (n == null) {
1403                        n = (Node) p; // found one node
1404                        wayIsFinished = false;
1405                    } else {
1406                        // if more than 1 node were affected by previous command,
1407                        // we have no way to continue, so we forget about found node
1408                        n = null;
1409                        break;
1410                    }
1411                }
1412            }
1413            // select last added node - maybe we will continue drawing from it
1414            if (n != null) {
1415                addSelection(getLayerManager().getEditDataSet(), n);
1416            }
1417        }
1418    }
1419
1420    private class SnapChangeAction extends JosmAction {
1421        /**
1422         * Constructs a new {@code SnapChangeAction}.
1423         */
1424        SnapChangeAction() {
1425            super(tr("Angle snapping"), /* ICON() */ "anglesnap",
1426                    tr("Switch angle snapping mode while drawing"), null, false);
1427            putValue("help", ht("/Action/Draw/AngleSnap"));
1428        }
1429
1430        @Override
1431        public void actionPerformed(ActionEvent e) {
1432            if (snapHelper != null) {
1433                snapHelper.toggleSnapping();
1434            }
1435        }
1436
1437        @Override
1438        protected void updateEnabledState() {
1439            MapFrame map = MainApplication.getMap();
1440            setEnabled(map != null && map.mapMode instanceof DrawAction);
1441        }
1442    }
1443}