--- a/gnv-artifacts/ChangeLog	Mon Dec 28 17:13:12 2009 +0000
+++ b/gnv-artifacts/ChangeLog	Tue Dec 29 06:53:31 2009 +0000
@@ -1,3 +1,17 @@
+2009-12-29	Sascha L. Teichmann	<sascha.teichmann@intevation.de>
+
+	* src/main/java/de/intevation/gnv/raster/Filter.java: New.
+	  General filter mechanism raster in -> raster out. Useful
+	  to chain processing. The Filter.Factory takes an 
+	  DOM element to configure itself.
+
+	* src/main/java/de/intevation/gnv/raster/KernelFilter.java:
+	  New. Implements raster filters based on kernel folding. Has
+	  an inner class GaussFactory which acts as a factory to create 
+	  Gauss filters. The attributes "sigma" and "radius" are read
+	  from the configuring DOM element to set up the parameters
+	  of the kernel.
+
 2009-12-28	Sascha L. Teichmann	<sascha.teichmann@intevation.de>
 
 	* src/main/java/de/intevation/gnv/state/profile/horizontal/HorizontalProfileMeshCrossOutputState.java,

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gnv-artifacts/src/main/java/de/intevation/gnv/raster/Filter.java	Tue Dec 29 06:53:31 2009 +0000
@@ -0,0 +1,20 @@
+package de.intevation.gnv.raster;
+
+import org.w3c.dom.Element;
+
+/**
+ * @author Sascha L. Teichmann (sascha.teichmann@intevation.de)
+ */
+public interface Filter
+{
+    public interface Factory {
+
+        void init(Element element);
+
+        Filter create();
+
+    } // interface Factory
+
+    Raster filter(Raster raster);
+}
+// vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8:

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gnv-artifacts/src/main/java/de/intevation/gnv/raster/KernelFilter.java	Tue Dec 29 06:53:31 2009 +0000
@@ -0,0 +1,70 @@
+package de.intevation.gnv.raster;
+
+import org.w3c.dom.Element;
+
+import org.apache.log4j.Logger;
+
+/**
+ * @author Sascha L. Teichmann (sascha.teichmann@intevation.de)
+ */
+public class KernelFilter
+implements   Filter
+{
+    private static Logger log = Logger.getLogger(KernelFilter.class);
+
+    public static class GaussFactory
+    implements          Filter.Factory
+    {
+        public static final double DEFAULT_SIGMA  = 1.0d;
+        public static final int    DEFAULT_RADIUS = 5;
+
+        protected double sigma;
+        protected int    radius;
+
+        public GaussFactory() {
+            sigma  = DEFAULT_SIGMA;
+            radius = DEFAULT_RADIUS;
+        }
+
+        public void init(Element element) {
+            String s = element.getAttribute("sigma");
+            String r = element.getAttribute("radius");
+
+            if ((s = s.trim()).length() > 0) {
+                try {
+                    sigma = Math.abs(Double.parseDouble(s));
+                }
+                catch (NumberFormatException nfe) {
+                    log.warn("gauss sigma '" + s + "' not a valid float value.");
+                }
+            }
+
+            if ((r = r.trim()).length() > 0) {
+                try {
+                    radius = Math.min(3, Math.abs(Integer.parseInt(r)));
+                }
+                catch (NumberFormatException nfe) {
+                    log.warn("gauss radius '" + r + "' not a valid integer value.");
+                }
+            }
+        }
+
+        public Filter create() {
+            return new KernelFilter(Raster.Kernel.createGauss(sigma, radius));
+        }
+    } // class GaussFactory
+
+    protected Raster.Kernel kernel;
+
+    public KernelFilter() {
+    }
+
+    public KernelFilter(Raster.Kernel kernel) {
+        this.kernel = kernel;
+    }
+
+    public Raster filter(Raster raster) {
+        return raster.create(kernel);
+    }
+}
+// vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8: