source: josm/trunk/src/org/openstreetmap/josm/command/RotateCommand.java@ 729

package org.openstreetmap.josm.command;

import static org.openstreetmap.josm.tools.I18n.tr;
import static org.openstreetmap.josm.tools.I18n.trn;

import java.util.Collection;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.Map;

import javax.swing.JLabel;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.MutableTreeNode;

import org.openstreetmap.josm.Main;
import org.openstreetmap.josm.data.coor.EastNorth;
import org.openstreetmap.josm.data.coor.LatLon;
import org.openstreetmap.josm.data.osm.Node;
import org.openstreetmap.josm.data.osm.OsmPrimitive;
import org.openstreetmap.josm.data.osm.visitor.AllNodesVisitor;
import org.openstreetmap.josm.tools.ImageProvider;

/**
 * RotateCommand rotates a number of objects around their centre.
 * 
 * @author Frederik Ramm <frederik@remote.org>
 */
public class RotateCommand extends Command {
        
        /**
         * The objects to rotate.
         */
        public Collection<Node> objects = new LinkedList<Node>();
        
        /**
         * pivot point
         */
        private Node pivot;
        
        /**
         * angle of rotation starting click to pivot
         */
        private double startAngle;
        
        /**
         * computed rotation angle between starting click and current mouse pos
         */
        private double rotationAngle;
        
        /**
         * List of all old states of the objects.
         */
        private Map<Node, MoveCommand.OldState> oldState = new HashMap<Node, MoveCommand.OldState>();
        
        /**
         * Creates a RotateCommand.
         * Assign the initial object set, compute pivot point and rotation angle.
         * Computation of pivot point is done by the same rules that are used in 
         * the "align nodes in circle" action.
         */
        public RotateCommand(Collection<OsmPrimitive> objects, EastNorth start, EastNorth end) {

                this.objects = AllNodesVisitor.getAllNodes(objects);
                pivot = new Node(new LatLon(0,0));
                        
                for (Node n : this.objects) {
                        MoveCommand.OldState os = new MoveCommand.OldState();
                        os.eastNorth = n.eastNorth;
                        os.latlon = n.coor;
                        os.modified = n.modified;
                        oldState.put(n, os);
                        pivot.eastNorth = new EastNorth(pivot.eastNorth.east()+os.eastNorth.east(), pivot.eastNorth.north()+os.eastNorth.north());
                        pivot.coor = Main.proj.eastNorth2latlon(pivot.eastNorth);
                }
                pivot.eastNorth = new EastNorth(pivot.eastNorth.east()/this.objects.size(), pivot.eastNorth.north()/this.objects.size());
                pivot.coor = Main.proj.eastNorth2latlon(pivot.eastNorth);       

                rotationAngle = Math.PI/2;
                rotateAgain(start, end);
        }

        /**
         * Rotate the same set of objects again, by the angle between given 
         * start and end nodes. Internally this is added to the existing
         * rotation so a later undo will undo the whole rotation.
         */
        public void rotateAgain(EastNorth start, EastNorth end) {
                // compute angle
                startAngle = Math.atan2(start.east()-pivot.eastNorth.east(), start.north()-pivot.eastNorth.north());
                double endAngle = Math.atan2(end.east()-pivot.eastNorth.east(), end.north()-pivot.eastNorth.north());
                rotationAngle += startAngle - endAngle;         
                rotateNodes(false);
        }
        
        /**
         * Helper for actually rotationg the nodes.
         * @param setModified - true if rotated nodes should be flagged "modified"
         */
        private void rotateNodes(boolean setModified) {
                for (Node n : objects) {
                        double cosPhi = Math.cos(rotationAngle);
                        double sinPhi = Math.sin(rotationAngle);
                        EastNorth oldEastNorth = oldState.get(n).eastNorth;
                        double x = oldEastNorth.east() - pivot.eastNorth.east();
                        double y = oldEastNorth.north() - pivot.eastNorth.north();
                        double nx =  sinPhi * x + cosPhi * y + pivot.eastNorth.east();
                        double ny = -cosPhi * x + sinPhi * y + pivot.eastNorth.north();
                        n.eastNorth = new EastNorth(nx, ny);
                        n.coor = Main.proj.eastNorth2latlon(n.eastNorth);
                        if (setModified)
                                n.modified = true;      
                }
        }
        
        @Override public boolean executeCommand() {
                rotateNodes(true);
                return true;
        }

        @Override public void undoCommand() {
                for (Node n : objects) {
                        MoveCommand.OldState os = oldState.get(n);
                        n.eastNorth = os.eastNorth;
                        n.coor = os.latlon;
                        n.modified = os.modified;
                }
        }

        @Override public void fillModifiedData(Collection<OsmPrimitive> modified, Collection<OsmPrimitive> deleted, Collection<OsmPrimitive> added) {
                for (OsmPrimitive osm : objects)
                        modified.add(osm);
        }

        @Override public MutableTreeNode description() {
                return new DefaultMutableTreeNode(new JLabel(tr("Rotate")+" "+objects.size()+" "+trn("node","nodes",objects.size()), ImageProvider.get("data", "node"), JLabel.HORIZONTAL));
    }
}