sascha@1794: package de.intevation.flys.geom;
sascha@1794: 
sascha@1794: import java.io.Serializable;
sascha@1794: 
sascha@1794: import java.awt.Shape;
sascha@1794: 
sascha@1794: import java.awt.geom.Path2D;
sascha@1794: import java.awt.geom.Point2D;
sascha@1794: 
sascha@1794: import java.util.ArrayList;
sascha@1794: import java.util.List;
sascha@1794: import java.util.Arrays;
sascha@1794: import java.util.Comparator;
sascha@1794: import java.util.Collections;
sascha@1794: 
sascha@1794: public class Polygon2D
sascha@1794: implements   Serializable
sascha@1794: {
sascha@1795:     private static final double X(Point2D p) {
sascha@1795:         return p.getX();
sascha@1795:     }
sascha@1795: 
sascha@1795:     private static final double Y(Point2D p) {
sascha@1795:         return p.getY();
sascha@1795:     }
sascha@1795: 
sascha@1794:     public static final Comparator<Point2D> POINT_X_CMP =
sascha@1794:         new Comparator<Point2D>() {
sascha@1794:             public int compare(Point2D a, Point2D b) {
sascha@1795:                 double d = X(a) - X(b);
sascha@1794:                 if (d < 0d) return -1;
sascha@1794:                 return d > 0d ? + 1 : 0;
sascha@1794:             }
sascha@1794:         };
sascha@1794: 
sascha@1794:     public static final Comparator<Point2D []> FIRST_POINT_X =
sascha@1794:         new Comparator<Point2D []>() {
sascha@1794:             public int compare(Point2D [] a, Point2D [] b) {
sascha@1794:                 if (a.length == 0) return -1; // should not happen.
sascha@1794:                 if (b.length == 0) return +1; // should not happen.
sascha@1795:                 double d = X(a[0]) - Y(b[0]);
sascha@1794:                 if (d < 0d) return -1;
sascha@1794:                 return d > 0d ? + 1 : 0;
sascha@1794:             }
sascha@1794:         };
sascha@1794: 
sascha@1795:     protected List<Point2D> points;
sascha@1794: 
sascha@1794:     public Polygon2D() {
sascha@1795:         points = new ArrayList<Point2D>();
sascha@1795:     }
sascha@1795: 
sascha@1794:     public void add(double x, double y) {
sascha@1795:         points.add(new Point2D.Double(x, y));
sascha@1795:     }
sascha@1795: 
sascha@1795:     public boolean addCheck(Point2D p) {
sascha@1795:         switch (points.size()) {
sascha@1795:             case 0:
sascha@1795:                 points.add(p);
sascha@1795:                 return true;
sascha@1795:             case 1:
sascha@1797:                 if (VectorUtils.epsilonEquals(points.get(0), p)) {
sascha@1795:                     return false;
sascha@1795:                 }
sascha@1795:                 points.add(p);
sascha@1795:                 return true;
sascha@1795:             default:
sascha@1795:                 int L = points.size()-1;
sascha@1795:                 Point2D last = points.get(L);
sascha@1797:                 if (VectorUtils.epsilonEquals(last, p)) {
sascha@1795:                     return false;
sascha@1795:                 }
sascha@1795:                 Point2D before = points.get(L-1);
sascha@1797:                 if (VectorUtils.collinear(before, last, p)) {
sascha@1795:                     points.set(L, p);
sascha@1795:                 }
sascha@1795:                 else {
sascha@1795:                     points.add(p);
sascha@1795:                 }
sascha@1795:                 return true;
sascha@1795:         }
sascha@1795:     }
sascha@1795: 
sascha@1795:     public void addReversed(List<Point2D> other) {
sascha@1795:         for (int i = other.size()-1; i >= 0; --i) {
sascha@1795:             addCheck(other.get(i));
sascha@1795:         }
sascha@1795:     }
sascha@1795: 
sascha@1794:     public double area() {
sascha@1794:         double area = 0d;
sascha@1794: 
sascha@1795: 		for (int i = 0, N = points.size(); i < N; ++i) {
sascha@1794: 			int j = (i + 1) % N;
sascha@1795:             Point2D pi = points.get(i);
sascha@1795:             Point2D pj = points.get(j);
sascha@1795: 			area += X(pi)*Y(pj);
sascha@1795: 			area -= X(pj)*Y(pi);
sascha@1794: 		}
sascha@1794: 
sascha@1794:         return 0.5d*area;
sascha@1794:     }
sascha@1794: 
sascha@1794:     public Shape toShape() {
sascha@1794:         Path2D.Double path = new Path2D.Double();
sascha@1794: 
sascha@1795:         int N = points.size();
sascha@1794: 
sascha@1794:         if (N > 0) {
sascha@1795:             Point2D p = points.get(0);
sascha@1795:             path.moveTo(X(p), Y(p));
sascha@1794:             for (int i = 1; i < N; ++i) {
sascha@1795:                 p = points.get(i);
sascha@1795:                 path.lineTo(X(p), Y(p));
sascha@1794:             }
sascha@1794:             path.closePath();
sascha@1794:         }
sascha@1794: 
sascha@1794:         return path;
sascha@1794:     }
sascha@1794: 
sascha@1794:     protected static List<Point2D []> splitByNaNs(
sascha@1794:         double [] xs,
sascha@1794:         double [] ys
sascha@1794:     ) {
sascha@1794:         List<Point2D []> parts = new ArrayList<Point2D []>();
sascha@1794: 
sascha@1794:         List<Point2D> tmp = new ArrayList<Point2D>(xs.length);
sascha@1794: 
sascha@1794:         for (int i = 0; i < xs.length; ++i) {
sascha@1794:             double x = xs[i];
sascha@1794:             double y = ys[i];
sascha@1794: 
sascha@1794:             if (Double.isNaN(x) || Double.isNaN(y)) {
sascha@1794:                 if (!tmp.isEmpty()) {
sascha@1794:                     Point2D [] part = new Point2D[tmp.size()];
sascha@1794:                     parts.add(tmp.toArray(part));
sascha@1794:                     tmp.clear();
sascha@1794:                 }
sascha@1794:             }
sascha@1794:             else {
sascha@1794:                 tmp.add(new Point2D.Double(x, y));
sascha@1794:             }
sascha@1794:         }
sascha@1794: 
sascha@1794:         if (!tmp.isEmpty()) {
sascha@1794:             Point2D [] part = new Point2D[tmp.size()];
sascha@1794:             parts.add(tmp.toArray(part));
sascha@1794:         }
sascha@1794: 
sascha@1794:         return parts;
sascha@1794:     }
sascha@1794: 
sascha@1795:     protected static boolean removeNoneIntersecting(
sascha@1795:         List<Point2D []> As,
sascha@1795:         List<Point2D []> Bs
sascha@1795:     ) {
sascha@1795:         OUTER: for (int i = 0; i < As.size();) {
sascha@1795:             Point2D [] a = As.get(i);
sascha@1795:             int lo = 0, hi = Bs.size()-1;
sascha@1795:             while (lo <= hi) {
sascha@1795:                 int mid = (lo + hi) >> 1;
sascha@1795:                 Point2D [] b = Bs.get(mid);
sascha@1795:                      if (X(a[0]) > X(b[b.length-1])) lo = mid+1;
sascha@1795:                 else if (X(a[a.length-1]) < X(b[0])) hi = mid-1;
sascha@1795:                 else {
sascha@1795:                     // found: keep
sascha@1795:                     ++i;
sascha@1795:                     continue OUTER;
sascha@1795:                 }
sascha@1795:             }
sascha@1795:             // not found: remove
sascha@1795:             As.remove(i);
sascha@1795:         }
sascha@1795: 
sascha@1795:         return As.isEmpty();
sascha@1795:     }
sascha@1795: 
sascha@1795:     protected static void buildPolygons(
sascha@1795:         Point2D []      as,
sascha@1795:         Point2D []      bs,
sascha@1795:         Point2D [][]    rest,
sascha@1795:         List<Polygon2D> positives,
sascha@1795:         List<Polygon2D> negatives
sascha@1795:     ) {
sascha@1795:     }
sascha@1795: 
sascha@1794:     public static void createPolygons(
sascha@1794:         double [] xAs, double [] yAs,
sascha@1794:         double [] xBs, double [] yBs,
sascha@1794:         List<Polygon2D> positives,
sascha@1794:         List<Polygon2D> negatives
sascha@1794:     ) {
sascha@1794:         if (xAs.length == 0 || xBs.length == 0) {
sascha@1794:             return;
sascha@1794:         }
sascha@1794: 
sascha@1794:         List<Point2D []> splAs = splitByNaNs(xAs, yAs);
sascha@1794:         List<Point2D []> splBs = splitByNaNs(xBs, yBs);
sascha@1794: 
sascha@1794:         // They feeded us with NaNs only.
sascha@1794:         if (splAs.isEmpty() || splBs.isEmpty()) {
sascha@1794:             return;
sascha@1794:         }
sascha@1794: 
sascha@1794:         // Sort each part by x to ensure that the first
sascha@1794:         // is the smallest.
sascha@1794:         for (Point2D [] splA: splAs) {
sascha@1794:             Arrays.sort(splA, POINT_X_CMP);
sascha@1794:         }
sascha@1794: 
sascha@1794:         for (Point2D [] splB: splBs) {
sascha@1794:             Arrays.sort(splB, POINT_X_CMP);
sascha@1794:         }
sascha@1794: 
sascha@1794:         // Now sort all parts by there first elements.
sascha@1794:         // Should be good enough to find overlapping regions.
sascha@1794:         Collections.sort(splAs, FIRST_POINT_X);
sascha@1794:         Collections.sort(splBs, FIRST_POINT_X);
sascha@1794: 
sascha@1794:         // Check if the two series intersect at all.
sascha@1794:         // If no then there will be no area between them.
sascha@1794: 
sascha@1794:         Point2D [] p1 = splAs.get(0);
sascha@1794:         Point2D [] p2 = splBs.get(splBs.size()-1);
sascha@1794: 
sascha@1795:         // Sort out the ranges that are not intersecting
sascha@1795:         // the ranges in the other series.
sascha@1795:         // We are going to merge them anyway
sascha@1795:         // so this is not strictly required. 
sascha@1795:         // Keep it to recude cases.
sascha@1795:         if (removeNoneIntersecting(splAs, splBs)
sascha@1795:         ||  removeNoneIntersecting(splBs, splAs)
sascha@1795:         ) {
sascha@1795:             // They do not intersect at all.
sascha@1794:             return;
sascha@1794:         }
sascha@1794: 
sascha@1794:         // TODO: Intersect/split the two series parts.
sascha@1794:     }
sascha@1794: }
sascha@1794: // vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 :