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.imgfmt.app.Area;
import uk.me.parabola.imgfmt.app.Coord;
import uk.me.parabola.log.Logger;
import uk.me.parabola.mkgmap.general.MapElement;
import uk.me.parabola.mkgmap.general.MapShape;
import uk.me.parabola.mkgmap.reader.osm.GType;
import uk.me.parabola.util.ShapeSplitter;

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 implements MapFilter {
        private static final Logger log = Logger.getLogger(PolygonSplitterFilter.class);

        public static final int MAX_POINT_IN_ELEMENT = 250;
        private int shift;
       
        @Override
        public void init(FilterConfig config) {
                shift = config.getShift();
        }
       
        /**
         * Split the given shape and place the resulting shapes in the outputs list.
         * @param shape The original shape (that is too big).
         * @param outputs The output list.
         */
        private void split(MapShape shape, List<MapShape> outputs) {
                int dividingLine = 0;
                boolean isLongitude = false;
                Area bounds = shape.getBounds();
                if (bounds.getWidth() > bounds.getHeight()) {
                        isLongitude = true;
                        Area[] tmpAreas = bounds.split(2, 1, shift);
                        dividingLine = tmpAreas != null ? tmpAreas[0].getMaxLong() : (bounds.getMinLong() + bounds.getWidth() / 2);
                } else {
                        Area[] tmpAreas = bounds.split(1, 2, shift);
                        dividingLine = tmpAreas != null ? tmpAreas[0].getMaxLat() : (bounds.getMinLat() + bounds.getHeight() / 2);
                }
                List<List<Coord>> subShapePoints = new ArrayList<>();
                ShapeSplitter.splitShape(shape.getPoints(), dividingLine << Coord.DELTA_SHIFT, isLongitude, subShapePoints, subShapePoints, null);
                for (List<Coord> subShape : subShapePoints) {
                        MapShape s = shape.copy();
                        s.setPoints(subShape);
                        outputs.add(s);
                }
        }

        /**
         * 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.
         */
        @Override
        public void doFilter(MapElement element, MapFilterChain next) {
                MapShape shape = (MapShape) element;

                try {
                        next.doFilter(shape);
                } catch (MustSplitException e) {
                        if (log.isDebugEnabled()) {
                                log.debug("splitting shape", GType.formatType(shape.getType()), "at shift", shift);
                        }
                        List<MapShape> outputs = new ArrayList<>();
                        split(shape, outputs); // split in half
                        for (MapShape s : outputs) {
                                doFilter(s, next); // recurse as components could still be too big
                        }
                }
        }

        // used for testing
        public List<MapShape> testSplit(MapShape shape, int shift) {
                this.shift = shift;
                List<MapShape> outputs = new ArrayList<>();
                split(shape, outputs); // split in half
                return outputs;
        }
}