001// License: GPL. For details, see LICENSE file.
002package org.openstreetmap.josm.command;
003
004import static org.openstreetmap.josm.tools.I18n.trn;
005
006import java.util.Collection;
007import java.util.Objects;
008
009import org.openstreetmap.josm.data.coor.EastNorth;
010import org.openstreetmap.josm.data.osm.Node;
011import org.openstreetmap.josm.data.osm.OsmPrimitive;
012
013/**
014 * Command, to scale a given set of primitives.
015 * The relative distance of the nodes will be increased/decreased.
016 */
017public class ScaleCommand extends TransformNodesCommand {
018    /**
019     * Pivot point
020     */
021    private final EastNorth pivot;
022
023    /**
024     * Current scaling factor applied
025     */
026    private double scalingFactor;
027
028    /**
029     * World position of the mouse when the user started the command.
030     */
031    private final EastNorth startEN;
032
033    /**
034     * Creates a ScaleCommand.
035     * Assign the initial object set, compute pivot point.
036     * Computation of pivot point is done by the same rules that are used in
037     * the "align nodes in circle" action.
038     * @param objects objects to fetch nodes from
039     * @param currentEN cuurent eats/north
040     */
041    public ScaleCommand(Collection<? extends OsmPrimitive> objects, EastNorth currentEN) {
042        super(objects);
043
044        pivot = getNodesCenter();
045
046        // We remember the very first position of the mouse for this action.
047        // Note that SelectAction will keep the same ScaleCommand when the user
048        // releases the button and presses it again with the same modifiers.
049        // The very first point of this operation is stored here.
050        startEN = currentEN;
051
052        handleEvent(currentEN);
053    }
054
055    /**
056     * Compute new scaling factor and transform nodes accordingly.
057     */
058    @Override
059    public final void handleEvent(EastNorth currentEN) {
060        double startAngle = Math.atan2(startEN.east()-pivot.east(), startEN.north()-pivot.north());
061        double endAngle = Math.atan2(currentEN.east()-pivot.east(), currentEN.north()-pivot.north());
062        double startDistance = pivot.distance(startEN);
063        double currentDistance = pivot.distance(currentEN);
064        setScalingFactor(Math.cos(startAngle-endAngle) * currentDistance / startDistance);
065        transformNodes();
066    }
067
068    /**
069     * Set the scaling factor
070     * @param scalingFactor The scaling factor.
071     */
072    protected void setScalingFactor(double scalingFactor) {
073        this.scalingFactor = scalingFactor;
074    }
075
076    /**
077     * Scale nodes.
078     */
079    @Override
080    protected void transformNodes() {
081        for (Node n : nodes) {
082            EastNorth oldEastNorth = oldStates.get(n).getEastNorth();
083            double dx = oldEastNorth.east() - pivot.east();
084            double dy = oldEastNorth.north() - pivot.north();
085            double nx = pivot.east() + scalingFactor * dx;
086            double ny = pivot.north() + scalingFactor * dy;
087            n.setEastNorth(new EastNorth(nx, ny));
088        }
089    }
090
091    @Override
092    public String getDescriptionText() {
093        return trn("Scale {0} node", "Scale {0} nodes", nodes.size(), nodes.size());
094    }
095
096    @Override
097    public int hashCode() {
098        return Objects.hash(super.hashCode(), pivot, scalingFactor, startEN);
099    }
100
101    @Override
102    public boolean equals(Object obj) {
103        if (this == obj) return true;
104        if (obj == null || getClass() != obj.getClass()) return false;
105        if (!super.equals(obj)) return false;
106        ScaleCommand that = (ScaleCommand) obj;
107        return Double.compare(that.scalingFactor, scalingFactor) == 0 &&
108                Objects.equals(pivot, that.pivot) &&
109                Objects.equals(startEN, that.startEN);
110    }
111}