Subversion Repositories mkgmap

/*
 * Copyright (C) 2007 Steve Ratcliffe
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 2 as
 *  published by the Free Software Foundation.
 *
 *  This program 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 General Public License for more details.
 *
 *
 * Author: Steve Ratcliffe
 * Create date: Dec 2, 2007
 */
package uk.me.parabola.mkgmap.filters;

import uk.me.parabola.mkgmap.general.MapElement;
import uk.me.parabola.mkgmap.general.MapShape;

import java.util.ArrayList;
import java.util.List;

/**
 * Split polygons so that they have less than the maximum number of points.
 *
 * @author Gerd Petermann
 */
public class PolygonSplitterFilter extends PolygonSplitterBase implements MapFilter {

        public static final int MAX_POINT_IN_ELEMENT = 250;

//      public PolygonSplitterFilter() {
//      }

        /**
         * This filter splits a polygon if any of the subsequent filters throws a
         * {@link MustSplitException}.
         * This will not happen often.
         *
         * @param element A map element, only polygons will be processed.
         * @param next  This is used to pass the possibly transformed element onward.
         */
        public void doFilter(MapElement element, MapFilterChain next) {
                assert element instanceof MapShape;
                MapShape shape = (MapShape) element;

                try {
                        next.doFilter(shape);
                } catch (MustSplitException e) {
                        List<MapShape> outputs = new ArrayList<MapShape>();
                        split(shape, outputs); // split in half
                        for (MapShape s : outputs) {
                                doFilter(s, next); // recurse as components could still be too big
                        }
                }
        }
}