Basic support for region area constraints.

git-svn-id: https://triangle.svn.codeplex.com/svn@79346 0e2699bc-83d4-4a8f-98e7-55e24ab8c7a5

Triangle.NET/Triangle/Geometry/RegionPointer.cs

@@ -17,6 +17,23 @@ namespace TriangleNet.Geometry
     {
         internal Point point;
         internal int id;
+        internal double area;
+
+        /// <summary>
+        /// Gets or sets a region area constraint.
+        /// </summary>
+        public double Area
+        {
+            get { return area; }
+            set
+            {
+                if (value < 0.0)
+                {
+                    throw new ArgumentException("Area constraints must not be negative.");
+                }
+                area = value;
+            }
+        }
 
         /// <summary>
         /// Initializes a new instance of the <see cref="RegionPointer" /> class.
@@ -25,9 +42,22 @@ namespace TriangleNet.Geometry
         /// <param name="y">Y coordinate of the region.</param>
         /// <param name="id">Region id.</param>
         public RegionPointer(double x, double y, int id)
+            : this(x, y, id, 0.0)
+        {
+        }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="RegionPointer" /> class.
+        /// </summary>
+        /// <param name="x">X coordinate of the region.</param>
+        /// <param name="y">Y coordinate of the region.</param>
+        /// <param name="id">Region id.</param>
+        /// <param name="area">Area constraint.</param>
+        public RegionPointer(double x, double y, int id, double area)
         {
             this.point = new Point(x, y);
             this.id = id;
+            this.area = area;
         }
     }
 }

Triangle.NET/Triangle/IO/TriangleReader.cs

@@ -446,7 +446,7 @@ namespace TriangleNet.IO
                 // Read area constraints (optional).
                 if (TryReadLine(reader, out line))
                 {
-                    int regions = int.Parse(line[0]);
+                    int id, regions = int.Parse(line[0]);
 
                     if (regions > 0)
                     {
@@ -462,10 +462,32 @@ namespace TriangleNet.IO
                                 throw new Exception("Invalid region attributes.");
                             }
 
+                            if (!int.TryParse(line[3], out id))
+                            {
+                                id = i;
+                            }
+
+                            double area = 0.0;
+
+                            if (line.Length > 4)
+                            {
+                                double.TryParse(line[4], NumberStyles.Number, nfi, out area);
+                            }
+
+                            // Triangle's .poly file format allows region definitions with
+                            // either 4 or 5 parameters, and different interpretations for
+                            // them depending on the number of parameters.
+                            //
+                            // See http://www.cs.cmu.edu/~quake/triangle.poly.html
+                            //
+                            // The .NET version will interpret the fourth parameter always
+                            // as an integer region id and the optional fifth parameter as
+                            // an area constraint.
+
                             data.Regions.Add(new RegionPointer(
                                 double.Parse(line[1], nfi), // Region x
                                 double.Parse(line[2], nfi), // Region y
-                                int.Parse(line[3]))); // Region id
+                                id, area));
                         }
                     }
                 }

Triangle.NET/Triangle/Meshing/ConstraintMesher.cs

@@ -186,6 +186,7 @@ namespace TriangleNet.Meshing
                                 // holes have been carved.
                                 regionTris[i] = searchtri.tri;
                                 regionTris[i].label = region.id;
+                                regionTris[i].area = region.area;
                             }
                         }
                     }

Triangle.NET/Triangle/Meshing/Iterators/RegionIterator.cs

@@ -92,7 +92,11 @@ namespace TriangleNet.Meshing.Iterators
         public void Process(Triangle triangle)
         {
             // Default action is to just set the region id for all trianlges.
-            this.Process(triangle, (tri) => { tri.label = triangle.label; });
+            this.Process(triangle, (tri) =>
+            {
+                tri.label = triangle.label;
+                tri.area = triangle.area;
+            });
         }
 
         /// <summary>