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.
 *
 */
package uk.me.parabola.mkgmap.filters;

import java.util.List;

import uk.me.parabola.imgfmt.app.Coord;
import uk.me.parabola.mkgmap.general.MapElement;
import uk.me.parabola.mkgmap.general.MapLine;

public class PreserveHorizontalAndVerticalLinesFilter implements MapFilter {

        private int shift;

        public void init(FilterConfig config) {
                shift = config.getShift();
        }

        /**
         * @param element A map element that will be a line or a polygon.
         * @param next This is used to pass the possibly transformed element onward.
         */
        public void doFilter(MapElement element, MapFilterChain next) {
                MapLine line = (MapLine) element;

                if(shift != 0) {
                        // preserve the end points of horizontal and vertical lines
                        List<Coord> points = line.getPoints();
                        Coord first = points.get(0);
                        Coord prev = first;
                        Coord last = first;
                        for(int i = 1; i < points.size(); ++i) {
                                last = points.get(i);
                                if(last.getLatitude() == prev.getLatitude() ||
                                   last.getLongitude() == prev.getLongitude()) {
                                        last.preserved(true);
                                        prev.preserved(true);
                                }
                                prev = last;
                        }
                        // if the way has the same point at each end, make sure
                        // that if either is preserved, they both are
                        if(first.equals(last) && first.preserved() != last.preserved()) {
                                first.preserved(true);
                                last.preserved(true);
                        }
                }

                next.doFilter(line);
        }
}