package jdraw.framework;

import java.awt.*;
import java.util.List;

/**
 * Base interface for all figures implemented in the grafic editor.
 * Every Figure-type has to implement this interface.
 *
 *
 * @author  Dominik Gruntz
 * @version 2.0, 26.04.01
 */
public interface Figure extends java.io.Serializable, Cloneable {

	/**
	 * Changes the bounds of the figure. The figure has to adjust its size
	 * and position when this method is called, and registered figure listeners
	 * have to be notified.
	 * @param origin the new origin
	 * @param corner the new corner
	 * @see #addFigureListener
	 */
	void setBounds(Point origin, Point corner);
	
	/**
	 * draw is called when the figure has to be drawn.
	 * @param g Graphics object on which figure has to be drawn.
	 * @see java.awt.Graphics
	 */
	void draw(Graphics g);
	
	/**
	 * Moves the figure. The figure has to adjust its coordinates 
	 * when this method is called, and registered figure listeners
	 * have to be notified.
	 * @param dx move distance in x direction (argument in pixels)
	 * @param dy move distance in y direction (argument in pixels)
	 * @see #addFigureListener
	 */
	void  move(int dx, int dy);
	
	/**
	 * Tests whether the mouse coordinates are contained in the figure.
	 * contains is called when the mouse is pressed in the grafic in
	 * order to decide which figure has to be selected.
	 * @param x x-coordinate of mouse position
	 * @param y y-coordinate of mouse position
	 * @return <tt>true</tt>, if coordinates are contained in the figure, 
	 *         <tt>false</tt> otherwise
	 */
	boolean contains(int x, int y);
	
	/**
	 * Returns the bounds of a figure. The bounds of a figure  is
	 * a rectangle which contains the figure.
	 * @return bounds of the figure
	 */
	Rectangle getBounds();
	
	/**
	 * Returns the center of a figure. The center is usually the center
	 * of its bounds rectangle.
	 * @return center of the figure
	 */
	Point getCenter();
	
	/**
	 * Returns a list of handles. Handles are used to manipulate a figure.
	 * If the figure does not support handles, <tt>null</tt> may be returned
	 * as result.
	 * @return list of handles (may be null if handles are not supported)
	 * @see Handle
	 */
	List  getHandles();
	
	/**
	 * Tests whether the figure is empty. This method may be called when a
	 * new figure is spawn in order to decide whether the figure should be
	 * included in the model or not. Empty figures may be discarded. This 
	 * behavior has to be implemented in the extensions of DrawTool.
	 * @return <tt>true</tt>, if figure is "empty"
	 *         <tt>false</tt> otherwise
	 * @see DrawTool
	 */
	boolean isEmpty();
	
	/**
	 * Adds the specified figure listener to receive figure events from 
	 * this figure. If listener is null, no exception is thrown and no 
	 * action is performed.
	 * @param listener the figure listener.
	 * @see FigureListener
	 */
	public void addFigureListener(FigureListener listener);
	
	/**
	 * Removes the specified figure listener so that it no longer receives
	 * figure events from this figure. This method performs no function, 
	 * nor does it throw an exception, if the listener specified by the 
	 * argument was not previously added to this figure. 
	 * If listener is null, no exception is thrown and no action is performed.
 	 * @param listener the figure listener.
	 * @see FigureListener
	 */
	public void removeFigureListener(FigureListener listener);
	
	/**
	 * Returns a Clone of this figure
	 * @return clone of figure
	 */	
	public Object clone();
	
}