sascha@360: package de.intevation.gnv.math;
sascha@360: 
sascha@360: import java.awt.geom.Point2D;
sascha@360: 
sascha@360: import java.util.List;
sascha@360: import java.util.Iterator;
sascha@360: import java.util.NoSuchElementException;
sascha@360: 
sascha@360: /**
sascha@360:  *  @author Sascha L. Teichmann
sascha@360:  */
sascha@360: public class LinearToMap
sascha@360: {
sascha@360:     public interface Interpolator {
sascha@360: 
sascha@360:         void interpolate(double t, Point2D v);
sascha@360: 
sascha@360:     } // interface Interpolator
sascha@360: 
sascha@360:     public interface Metrics {
sascha@360: 
sascha@360:         double distance(Point2D p1, Point2D p2);
sascha@360: 
sascha@360:         Interpolator getInterpolator(Point2D p1, Point2D p2);
sascha@360: 
sascha@360:     } // interface Metrics
sascha@360: 
sascha@360:     public static final class Range {
sascha@360:         private Range next;
sascha@360: 
sascha@360:         private double from;
sascha@360:         private double to;
sascha@360:         private double b;
sascha@360: 
sascha@360:         private Point2D p1;
sascha@360:         private Point2D p2;
sascha@360: 
sascha@360:         private Interpolator interpolator;
sascha@360: 
sascha@360:         public Range() {
sascha@360:         }
sascha@360: 
sascha@360:         public Range(
sascha@360:             double       from, 
sascha@360:             double       to,
sascha@360:             Interpolator interpolator,
sascha@360:             Point2D      p1,
sascha@360:             Point2D      p2
sascha@360:         ) {
sascha@360:             this.from         = from;
sascha@360:             this.to           = to;
sascha@360:             this.interpolator = interpolator;
sascha@360:             this.p1           = p1;
sascha@360:             this.p2           = p2;
sascha@360: 
sascha@360:             b = from == to
sascha@360:                 ? 0d
sascha@360:                 : 1.0d/(to - from);
sascha@360:         }
sascha@360: 
sascha@360:         public void eval(double x, Point2D v) {
sascha@360:             interpolator.interpolate((x - from)*b, v);
sascha@360:         }
sascha@360: 
sascha@360:         public boolean inside(double x) {
sascha@360:             return x >= from && x <= to;
sascha@360:         }
sascha@360: 
sascha@360:         public Point2D startPoint() {
sascha@360:             return p1;
sascha@360:         }
sascha@360: 
sascha@360:         public Point2D endPoint() {
sascha@360:             return p2;
sascha@360:         }
sascha@360:     } // class Range
sascha@360: 
sascha@360:     protected Range head;
sascha@360:     protected Range last;
sascha@360: 
sascha@360:     public LinearToMap() {
sascha@360:     }
sascha@360: 
sascha@360:     public LinearToMap(
sascha@360:         List    path, 
sascha@360:         double  from, 
sascha@360:         double  to,
sascha@360:         Metrics metrics
sascha@360:     ) {
sascha@360:         double diagramLength = Math.abs(to - from);
sascha@360: 
sascha@360:         double worldLength = length(path, metrics);
sascha@360: 
sascha@360:         double rangeStart = from;
sascha@360: 
sascha@360:         Range last = null;
sascha@360: 
sascha@360:         for (int i = 1, N = path.size(); i < N; ++i) {
sascha@360:             Point2D p1 = (Point2D)path.get(i-1);
sascha@360:             Point2D p2 = (Point2D)path.get(i);
sascha@360:             double segmentLength = metrics.distance(p1, p2);
sascha@360: 
sascha@360:             double relativeLength = segmentLength / worldLength;
sascha@360: 
sascha@360:             double rangeLength = diagramLength * relativeLength;
sascha@360: 
sascha@360:             double rangeEnd = rangeStart + rangeLength;
sascha@360: 
sascha@360:             Range range = new Range(
sascha@360:                 rangeStart, rangeEnd,
sascha@360:                 metrics.getInterpolator(p1, p2),
sascha@360:                 p1, p2);
sascha@360: 
sascha@360:             if (last == null) {
sascha@360:                 last = head = range;
sascha@360:             }
sascha@360:             else {
sascha@360:                 last.next = range;
sascha@360:                 last = range;
sascha@360:             }
sascha@360:             rangeStart = rangeEnd;
sascha@360:         }
sascha@360:     }
sascha@360: 
sascha@360:     protected Range locateRange(double diagramX) {
sascha@360: 
sascha@360:         if (last != null && last.inside(diagramX)) {
sascha@360:             return last;
sascha@360:         }
sascha@360: 
sascha@360:         Range current = head;
sascha@360:         while (current != null) {
sascha@360:             if (current.inside(diagramX)) {
sascha@360:                 return last = current;
sascha@360:             }
sascha@360:             current = current.next;
sascha@360:         }
sascha@360: 
sascha@360:         return null;
sascha@360:     }
sascha@360: 
sascha@360:     public boolean locate(double diagramX, Point2D v) {
sascha@360:         Range range = locateRange(diagramX);
sascha@360:         if (range == null) {
sascha@360:             return false;
sascha@360:         }
sascha@360:         range.eval(diagramX, v);
sascha@360:         return true;
sascha@360:     }
sascha@360: 
sascha@360:     public static double length(List path, Metrics metrics) {
sascha@360:         double sum = 0d;
sascha@360:         for (int i = path.size()-1; i >= 1; --i) {
sascha@360:             Point2D p1 = (Point2D)path.get(i);
sascha@360:             Point2D p2 = (Point2D)path.get(i-1);
sascha@360:             sum += metrics.distance(p1, p2);
sascha@360:         }
sascha@360:         return sum;
sascha@360:     }
sascha@360: 
sascha@360:     public int numRanges() {
sascha@360:         int count = 0;
sascha@360:         Range current = head;
sascha@360:         while (current != null) {
sascha@360:             ++count;
sascha@360:             current = current.next;
sascha@360:         }
sascha@360:         return count;
sascha@360:     }
sascha@360: 
sascha@360:     public Iterator ranges() {
sascha@360:         return new Iterator() {
sascha@360: 
sascha@360:             Range current = head;
sascha@360: 
sascha@360:             public boolean hasNext() {
sascha@360:                 return current != null;
sascha@360:             }
sascha@360: 
sascha@360:             public Object next() {
sascha@360:                 if (!hasNext()) {
sascha@360:                     throw new NoSuchElementException();
sascha@360:                 }
sascha@360:                 Range x = current;
sascha@360:                 current = current.next;
sascha@360:                 return x;
sascha@360:             }
sascha@360: 
sascha@360:             public void remove() {
sascha@360:                 throw new UnsupportedOperationException();
sascha@360:             }
sascha@360:         };
sascha@360:     }
sascha@360: }
sascha@360: // vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8: