--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gnv-artifacts/src/main/java/de/intevation/gnv/raster/IsoAttributeGenerator.java	Fri Sep 28 12:14:00 2012 +0200
@@ -0,0 +1,56 @@
+/*
+ * 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.raster;
+
+/**
+ * Generates label attributes for iso lines. It takes the
+ * neighboring palette ranges and calculates the mid point
+ * between these two ranges.
+ * @author <a href="mailto:sascha.teichmann@intevation.de">Sascha L. Teichmann</a>
+ */
+public class IsoAttributeGenerator
+implements   IsoProducer.AttributeGenerator
+{
+    /**
+     * The palette where to look for the ranges.
+     */
+    protected Palette palette;
+
+    /**
+     * Default constructor.
+     */
+    public IsoAttributeGenerator() {
+    }
+
+    /**
+     * Constructor to create an IsoAttributeGenerator with
+     * a given lookup palette.
+     * @param palette The palette.
+     */
+    public IsoAttributeGenerator(Palette palette) {
+        this.palette = palette;
+    }
+
+    public Object generateAttribute(int neighbor1, int neighbor2) {
+        Palette.Entry e1 = palette.getEntryByIndex(neighbor1);
+        Palette.Entry e2 = palette.getEntryByIndex(neighbor2);
+
+        if (e1 == null || e2 == null) {
+            return null;
+        }
+
+        double e1t = e1.getFrom();
+        double e2f = e2.getTo();
+
+        return Double.valueOf(e2f >= e1t
+            ? 0.5d*(e1t+e2f)
+            : 0.5d*(e2.getTo()+e1.getFrom()));
+    }
+}
+// vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 :