/*
 * @(#)OffsetLocator.java 5.2
 *
 */

package CH.ifa.draw.standard;

import java.awt.*;
import java.io.IOException;
import CH.ifa.draw.framework.*;
import CH.ifa.draw.util.*;

/**
 * A locator to offset another Locator.
 * @see Locator
 */
public  class OffsetLocator extends AbstractLocator {

    /*
     * Serialization support.
     */
    private static final long serialVersionUID = 2679950024611847621L;
    private int offsetLocatorSerializedDataVersion = 1;

    private Locator fBase;
    private int     fOffsetX;
    private int     fOffsetY;

    public OffsetLocator() {
        fBase = null;
        fOffsetX = 0;
        fOffsetY = 0;
    }

    public OffsetLocator(Locator base) {
        this();
        fBase = base;
    }

    public OffsetLocator(Locator base, int offsetX, int offsetY) {
        this(base);
        fOffsetX = offsetX;
        fOffsetY = offsetY;
    }

    public Point locate(Figure owner) {
        Point p = fBase.locate(owner);
        p.x += fOffsetX;
        p.y += fOffsetY;
        return p;
    }

    public void moveBy(int dx, int dy) {
        fOffsetX += dx;
        fOffsetY += dy;
    }

    public void write(StorableOutput dw) {
        super.write(dw);
        dw.writeInt(fOffsetX);
        dw.writeInt(fOffsetY);
        dw.writeStorable(fBase);
    }

    public void read(StorableInput dr) throws IOException {
        super.read(dr);
        fOffsetX = dr.readInt();
        fOffsetY = dr.readInt();
        fBase = (Locator)dr.readStorable();
    }
}