//
// $Id: SmartPolygon.java,v 1.5 2003/10/10 17:49:25 mdb Exp $
//
// samskivert library - useful routines for java programs
// Copyright (C) 2001 Michael Bayne
// 
// This library is free software; you can redistribute it and/or modify it
// under the terms of the GNU Lesser General Public License as published
// by the Free Software Foundation; either version 2.1 of the License, or
// (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

package com.samskivert.swing;

import java.awt.Polygon;
import java.awt.Rectangle;

/**
 * Extends the AWT polygon class and provides a {@link #getBounds} method
 * that doesn't annoyingly make a copy of the bounds rectangle every time
 * it is returned.
 */
public class SmartPolygon extends Polygon
{
    /**
     * Returns the internally cached bounds rectangle for this polygon.
     * <em>Don't modify it!</em>
     */
    public Rectangle getBoundingBox ()
    {
        if (bounds == null) {
            // this is inlined from Polygon.getBoundingBox() and
            // Polygon.computeBounds() because we can't call
            // super.getBoundingBox() without the compiler bitching about
            // deprecation, we can't just override getBounds() because a
            // few methods in Polygon still call getBoundingBox() and we
            // can't call computeBounds() because it's package protected
            // (thank's Sun!)
            if (npoints == 0) {
                bounds = new Rectangle();
            } else {
                int boundsMinX = Integer.MAX_VALUE;
                int boundsMinY = Integer.MAX_VALUE;
                int boundsMaxX = Integer.MIN_VALUE;
                int boundsMaxY = Integer.MIN_VALUE;
	
                for (int i = 0; i < npoints; i++) {
                    int x = xpoints[i];
                    boundsMinX = Math.min(boundsMinX, x);
                    boundsMaxX = Math.max(boundsMaxX, x);
                    int y = ypoints[i];
                    boundsMinY = Math.min(boundsMinY, y);
                    boundsMaxY = Math.max(boundsMaxY, y);
                }
                bounds = new Rectangle(boundsMinX, boundsMinY,
                                       boundsMaxX - boundsMinX,
                                       boundsMaxY - boundsMinY);
            }
        }
        return bounds;
    }
}
