--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gnv-artifacts/src/main/java/de/intevation/gnv/math/LinearMetrics.java	Fri Sep 28 12:14:00 2012 +0200
@@ -0,0 +1,81 @@
+/*
+ * Copyright (c) 2010 by Intevation GmbH
+ *
+ * This program is free software under the LGPL (>=v2.1)
+ * Read the file LGPL.txt coming with the software for details
+ * or visit http://www.gnu.org/licenses/ if it does not exist.
+ */
+
+package de.intevation.gnv.math;
+
+import com.vividsolutions.jts.geom.Coordinate;
+
+/**
+ * Implements {@link de.intevation.gnv.math.Metrics}
+ * for linear interpolations and distance measurements.
+ * @author <a href="mailto:sascha.teichmann@intevation.de">Sascha L. Teichmann</a>
+ */
+public final class LinearMetrics
+implements         Metrics
+{
+    /**
+     * Instance to prevent needless creations of instances.
+     */
+    public static final Metrics INSTANCE =
+        new LinearMetrics();
+
+    /**
+     * Implements the corresponding linear interpolator.
+     */
+    public static final class LinearInterpolator
+    implements                Interpolator
+    {
+        private double mx;
+        private double bx;
+        private double my;
+        private double by;
+
+        /**
+         * Constructor to create a linear interpolator between two
+         * given points.
+         * @param p1 The first point.
+         * @param p2 The second point.
+         */
+        public LinearInterpolator(Coordinate p1, Coordinate p2) {
+
+            /*
+             I) p1.x = 0*m + bx
+            II) p2.x = 1*m + bx
+
+            bx = p1.x
+
+            p2.x = m + p1.x
+
+            mx = p2.x - p1.x
+            */
+
+            bx = p1.x;
+            mx = p2.x - bx;
+
+            by = p1.y;
+            my = p2.y - by;
+        }
+
+        public void interpolate(double t, Coordinate v) {
+            v.x = t*mx + bx;
+            v.y = t*my + by;
+        }
+    } // class LinearInterpolator
+
+    private LinearMetrics() {
+    }
+
+    public double distance(Coordinate p1, Coordinate p2) {
+        return p1.distance(p2);
+    }
+
+    public Interpolator getInterpolator(Coordinate p1, Coordinate p2) {
+        return new LinearInterpolator(p1, p2);
+    }
+}
+// vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 :