/*
 * @(#)RelativeLocator.java
 *
 * Project:		JHotdraw - a GUI framework for technical drawings
 *				http://www.jhotdraw.org
 *				http://jhotdraw.sourceforge.net
 * Copyright:	© by the original author(s) and all contributors
 * License:		Lesser GNU Public License (LGPL)
 *				http://www.opensource.org/licenses/lgpl-license.html
 */

package CH.ifa.draw.standard;

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

/**
 * A locator that specfies a point that is relative to the bounds
 * of a figure.
 *
 * @see Locator
 *
 * @version <$CURRENT_VERSION$>
 */
public class RelativeLocator extends AbstractLocator {
	/*
	 * Serialization support.
	 */
	private static final long serialVersionUID = 2619148876087898602L;
	private int relativeLocatorSerializedDataVersion = 1;

	double  fRelativeX;
	double  fRelativeY;

	public RelativeLocator() {
		fRelativeX = 0.0;
		fRelativeY = 0.0;
	}

	public boolean equals(Object o) {
		if (RelativeLocator.class.isInstance(o)) {
			RelativeLocator rl = (RelativeLocator) o;
			if ((rl.fRelativeX) == fRelativeX && (rl.fRelativeY == fRelativeY)) {
				return true;
			}
		}
		return false;
	}

	public RelativeLocator(double relativeX, double relativeY) {
		fRelativeX = relativeX;
		fRelativeY = relativeY;
	}

	public Point locate(Figure owner) {
		Rectangle r = owner.displayBox();
		return new Point(
			r.x + (int)(r.width * fRelativeX),
			r.y + (int)(r.height * fRelativeY)
		);
	}

	public void write(StorableOutput dw) {
		super.write(dw);
		dw.writeDouble(fRelativeX);
		dw.writeDouble(fRelativeY);
	}

	public void read(StorableInput dr) throws IOException {
		super.read(dr);
		fRelativeX = dr.readDouble();
		fRelativeY = dr.readDouble();
	}

	static public Locator east() {
		return new RelativeLocator(1.0, 0.5);
	}

	/**
	 * North.
	 */
	static public Locator north() {
		return new RelativeLocator(0.5, 0.0);
	}

	/**
	 * West.
	 */
	static public Locator west() {
		return new RelativeLocator(0.0, 0.5);
	}

	/**
	 * North east.
	 */
	static public Locator northEast() {
		return new RelativeLocator(1.0, 0.0);
	}

	/**
	 * North west.
	 */
	static public Locator northWest() {
		return new RelativeLocator(0.0, 0.0);
	}

	/**
	 * South.
	 */
	static public Locator south() {
		return new RelativeLocator(0.5, 1.0);
	}

	/**
	 * South east.
	 */
	static public Locator southEast() {
		return new RelativeLocator(1.0, 1.0);
	}

	/**
	 * South west.
	 */
	static public Locator southWest() {
		return new RelativeLocator(0.0, 1.0);
	}

	/**
	 * Center.
	 */
	static public Locator center() {
		return new RelativeLocator(0.5, 0.5);
	}
}