Add examples project.

src/Triangle.Examples/Examples/Example4.cs

@@ -0,0 +1,69 @@
+
+namespace TriangleNet.Examples
+{
+    using TriangleNet;
+    using TriangleNet.Geometry;
+    using TriangleNet.Meshing;
+    using TriangleNet.Rendering.Text;
+    using TriangleNet.Smoothing;
+
+    /// <summary>
+    /// Refine only a part of a polygon mesh be using region pointers and an area constraint.
+    /// </summary>
+    public class Example4
+    {
+        public static void Run(bool print = false)
+        {
+            // Generate the input geometry.
+            var poly = CreatePolygon();
+            
+            // Define regions (first one defines the area constraint).
+            poly.Regions.Add(new RegionPointer(1.5, 0.0, 1, 0.01));
+            poly.Regions.Add(new RegionPointer(2.5, 0.0, 2));
+
+            // Set quality and constraint options.
+            var options = new ConstraintOptions()
+            {
+                ConformingDelaunay = true
+            };
+
+            var quality = new QualityOptions()
+            {
+                MinimumAngle = 25.0,
+                VariableArea = true
+            };
+
+            //quality.UserTest = (t, area) => t.Label == 1 && area > 0.01;
+
+            var mesh = poly.Triangulate(options, quality);
+
+            var smoother = new SimpleSmoother();
+
+            smoother.Smooth(mesh, 5);
+
+            if (print) SvgImage.Save(mesh, "example-4.png", 500);
+        }
+
+        public static IPolygon CreatePolygon()
+        {
+            // Generate three concentric circles.
+            var poly = new Polygon();
+
+            // Center point.
+            var center = new Point(0, 0);
+
+            // Inner contour (hole).
+            poly.Add(Generate.Circle(1.0, center, 0.1, 1), center);
+
+            // Internal contour.
+            poly.Add(Generate.Circle(2.0, center, 0.1, 2));
+
+            // Outer contour.
+            poly.Add(Generate.Circle(3.0, center, 0.3, 3));
+
+            // Note that the outer contour has a larger segment size!
+
+            return poly;
+        }
+    }
+}