Add delaunay triangle generation to Geometry (#67)

Author: jericks

src/main/java/org/geoscript/js/geom/Geometry.java

@@ -11,6 +11,8 @@
 import org.geotools.geometry.jts.GeometryCoordinateSequenceTransformer;
 import org.geotools.geometry.jts.ReferencedEnvelope;
 import org.geotools.referencing.CRS;
+import org.locationtech.jts.triangulate.ConformingDelaunayTriangulationBuilder;
+import org.locationtech.jts.triangulate.DelaunayTriangulationBuilder;
 import org.mozilla.javascript.Context;
 import org.mozilla.javascript.FunctionObject;
 import org.mozilla.javascript.NativeArray;
@@ -312,6 +314,24 @@ public ScriptableObject randomPoints(int number) {
         return points;
     }
 
+    @JSFunction
+    public ScriptableObject createDelaunayTriangles(boolean isConforming) {
+        org.locationtech.jts.geom.Geometry geom;
+        if (isConforming) {
+            ConformingDelaunayTriangulationBuilder builder = new ConformingDelaunayTriangulationBuilder();
+            builder.setSites(geometry);
+            geom = builder.getTriangles(factory);
+        }
+        else {
+            DelaunayTriangulationBuilder builder = new DelaunayTriangulationBuilder();
+            builder.setSites(geometry);
+            geom = builder.getTriangles(factory);
+        }
+        ScriptableObject triangles = GeometryWrapper.wrap(getParentScope(), geom);
+        ((Geometry) triangles).projection = projection;
+        return triangles;
+    }
+
     @JSFunction
     public String getGeometryType() {
         return geometry.getGeometryType();

src/test/resources/org/geoscript/js/tests/geoscript/test_geom.js

@@ -163,6 +163,27 @@ exports["test: create random points"] = function() {
     var points = geom.randomPoints(10)
     ASSERT.ok(points instanceof GEOM.MultiPoint)
     ASSERT.strictEqual(points.components.length, 10, "geometry has 10 components");
+
+}
+
+exports["test: create conforming delaunay triangles"] = function() {
+
+    var geom = GEOM.Point([1,1]).buffer(50)
+    var points = geom.randomPoints(20)
+    var triangles = points.createDelaunayTriangles(true)
+    ASSERT.ok(triangles instanceof GEOM.GeometryCollection)
+    ASSERT.ok(triangles.components.length > 0, "there should be more than 0 triangles");
+
+}
+
+exports["test: create non-conforming delaunay triangles"] = function() {
+
+    var geom = GEOM.Point([1,1]).buffer(50)
+    var points = geom.randomPoints(20)
+    var triangles = points.createDelaunayTriangles(false)
+    ASSERT.ok(triangles instanceof GEOM.GeometryCollection)
+    ASSERT.ok(triangles.components.length > 0, "there should be more than 0 triangles");
+
 }