ingo@1115: /*
ingo@1115:  * Copyright (c) 2010 by Intevation GmbH
ingo@1115:  *
ingo@1115:  * This program is free software under the LGPL (>=v2.1)
ingo@1115:  * Read the file LGPL.txt coming with the software for details
ingo@1115:  * or visit http://www.gnu.org/licenses/ if it does not exist.
ingo@1115:  */
ingo@1115: 
sascha@360: package de.intevation.gnv.math;
sascha@360: 
sascha@361: import com.vividsolutions.jts.geom.Coordinate;
sascha@360: 
sascha@360: /**
sascha@805:  * Implements {@link de.intevation.gnv.math.Metrics}
sascha@805:  * for linear interpolations and distance measurements.
sascha@798:  * @author <a href="mailto:sascha.teichmann@intevation.de">Sascha L. Teichmann</a>
sascha@360:  */
sascha@360: public final class LinearMetrics
sascha@360: implements         Metrics
sascha@360: {
sascha@805:     /**
sascha@805:      * Instance to prevent needless creations of instances.
sascha@805:      */
sascha@360:     public static final Metrics INSTANCE =
sascha@360:         new LinearMetrics();
sascha@360: 
sascha@805:     /**
sascha@805:      * Implements the corresponding linear interpolator.
sascha@805:      */
sascha@360:     public static final class LinearInterpolator
sascha@360:     implements                Interpolator
sascha@360:     {
sascha@360:         private double mx;
sascha@360:         private double bx;
sascha@360:         private double my;
sascha@360:         private double by;
sascha@360: 
sascha@805:         /**
sascha@805:          * Constructor to create a linear interpolator between two
sascha@805:          * given points.
sascha@805:          * @param p1 The first point.
sascha@805:          * @param p2 The second point.
sascha@805:          */
sascha@361:         public LinearInterpolator(Coordinate p1, Coordinate p2) {
sascha@360: 
sascha@360:             /*
sascha@360:              I) p1.x = 0*m + bx
sascha@360:             II) p2.x = 1*m + bx
sascha@360: 
sascha@360:             bx = p1.x
sascha@360: 
sascha@360:             p2.x = m + p1.x
sascha@360: 
sascha@360:             mx = p2.x - p1.x
sascha@360:             */
sascha@360: 
sascha@361:             bx = p1.x;
sascha@361:             mx = p2.x - bx;
sascha@360: 
sascha@361:             by = p1.y;
sascha@361:             my = p2.y - by;
sascha@360:         }
sascha@360: 
sascha@361:         public void interpolate(double t, Coordinate v) {
sascha@361:             v.x = t*mx + bx;
sascha@361:             v.y = t*my + by;
sascha@360:         }
sascha@360:     } // class LinearInterpolator
sascha@360: 
sascha@360:     private LinearMetrics() {
sascha@360:     }
sascha@360: 
sascha@361:     public double distance(Coordinate p1, Coordinate p2) {
sascha@360:         return p1.distance(p2);
sascha@360:     }
sascha@360: 
sascha@361:     public Interpolator getInterpolator(Coordinate p1, Coordinate p2) {
sascha@360:         return new LinearInterpolator(p1, p2);
sascha@360:     }
sascha@360: }
sascha@836: // vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 :