Cancellation option is added to Triangulate, Refine and Smooth methods

src/Triangle/Geometry/ExtensionMethods.cs

@@ -1,7 +1,7 @@
 
 namespace TriangleNet.Geometry
 {
-    using System;
+    using System.Threading;
     using TriangleNet.Meshing;
 
     /// <summary>
@@ -34,9 +34,10 @@ public static IMesh Triangulate(this IPolygon polygon, ConstraintOptions options
         /// </summary>
         /// <param name="polygon">Polygon instance.</param>
         /// <param name="quality">Quality options.</param>
-        public static IMesh Triangulate(this IPolygon polygon, QualityOptions quality)
+        /// <param name="cancellationToken">A token that receives a cancellation notification when requested.</param>
+        public static IMesh Triangulate(this IPolygon polygon, QualityOptions quality, CancellationToken cancellationToken = default)
         {
-            return (new GenericMesher()).Triangulate(polygon, null, quality);
+            return (new GenericMesher()).Triangulate(polygon, null, quality, cancellationToken);
         }
 
         /// <summary>
@@ -45,9 +46,10 @@ public static IMesh Triangulate(this IPolygon polygon, QualityOptions quality)
         /// <param name="polygon">Polygon instance.</param>
         /// <param name="options">Constraint options.</param>
         /// <param name="quality">Quality options.</param>
-        public static IMesh Triangulate(this IPolygon polygon, ConstraintOptions options, QualityOptions quality)
+        /// <param name="cancellationToken">A token that receives a cancellation notification when requested.</param>
+        public static IMesh Triangulate(this IPolygon polygon, ConstraintOptions options, QualityOptions quality, CancellationToken cancellationToken = default)
         {
-            return (new GenericMesher()).Triangulate(polygon, options, quality);
+            return (new GenericMesher()).Triangulate(polygon, options, quality, cancellationToken);
         }
 
         /// <summary>

src/Triangle/Mesh.cs

@@ -9,6 +9,7 @@ namespace TriangleNet
 {
     using System;
     using System.Collections.Generic;
+    using System.Threading;
     using TriangleNet.Geometry;
     using TriangleNet.Meshing;
     using TriangleNet.Meshing.Data;
@@ -224,7 +225,8 @@ public Mesh(Configuration config, IList<Vertex> points)
         /// </summary>
         /// <param name="quality">The quality constraints.</param>
         /// <param name="delaunay">A value indicating, whether the refined mesh should be Conforming Delaunay.</param>
-        public void Refine(QualityOptions quality, bool delaunay = false)
+        /// <param name="cancellationToken">A token that receives a cancellation notification when requested.</param>
+        public void Refine(QualityOptions quality, bool delaunay = false, CancellationToken cancellationToken = default)
         {
             invertices = vertices.Count;
 
@@ -241,7 +243,7 @@ public void Refine(QualityOptions quality, bool delaunay = false)
             }
 
             // Enforce angle and area constraints.
-            qualityMesher.Apply(quality, delaunay);
+            qualityMesher.Apply(quality, delaunay, cancellationToken);
         }
 
         /// <summary>

src/Triangle/Meshing/GenericMesher.cs

@@ -8,6 +8,7 @@ namespace TriangleNet.Meshing
 {
     using System;
     using System.Collections.Generic;
+    using System.Threading;
     using TriangleNet.Geometry;
     using TriangleNet.IO;
     using TriangleNet.Meshing.Algorithm;
@@ -96,10 +97,11 @@ public IMesh Triangulate(IPolygon polygon, ConstraintOptions options)
         /// </summary>
         /// <param name="polygon">The input polygon.</param>
         /// <param name="quality">The <see cref="QualityOptions"/>.</param>
+        /// <param name="cancellationToken">A token that receives a cancellation notification when requested.</param>
         /// <returns>The mesh.</returns>
-        public IMesh Triangulate(IPolygon polygon, QualityOptions quality)
+        public IMesh Triangulate(IPolygon polygon, QualityOptions quality, CancellationToken cancellationToken = default)
         {
-            return Triangulate(polygon, null, quality);
+            return Triangulate(polygon, null, quality, cancellationToken);
         }
 
         /// <summary>
@@ -108,8 +110,9 @@ public IMesh Triangulate(IPolygon polygon, QualityOptions quality)
         /// <param name="polygon">The input polygon.</param>
         /// <param name="options">The <see cref="ConstraintOptions"/>.</param>
         /// <param name="quality">The <see cref="QualityOptions"/>.</param>
+        /// <param name="cancellationToken">A token that receives a cancellation notification when requested.</param>
         /// <returns>The mesh.</returns>
-        public IMesh Triangulate(IPolygon polygon, ConstraintOptions options, QualityOptions quality)
+        public IMesh Triangulate(IPolygon polygon, ConstraintOptions options, QualityOptions quality, CancellationToken cancellationToken = default)
         {
             var mesh = (Mesh)triangulator.Triangulate(polygon.Points, config);
 
@@ -122,7 +125,7 @@ public IMesh Triangulate(IPolygon polygon, ConstraintOptions options, QualityOpt
             cmesher.Apply(polygon, options);
 
             // Refine mesh.
-            qmesher.Apply(quality);
+            qmesher.Apply(quality, options?.ConformingDelaunay ?? false, cancellationToken);
 
             return mesh;
         }

src/Triangle/Meshing/IMesh.cs

@@ -2,6 +2,7 @@
 namespace TriangleNet.Meshing
 {
     using System.Collections.Generic;
+    using System.Threading;
     using TriangleNet.Topology;
     using TriangleNet.Geometry;
 
@@ -49,9 +50,8 @@ public interface IMesh
         /// Refine the mesh.
         /// </summary>
         /// <param name="quality">The quality constraints.</param>
-        /// <param name="delaunay">
-        /// A value indicating, whether the refined mesh should be Conforming Delaunay.
-        /// </param>
-        void Refine(QualityOptions quality, bool delaunay);
+        /// <param name="delaunay">A value indicating, whether the refined mesh should be Conforming Delaunay.</param>
+        /// <param name="cancellationToken">A token that receives a cancellation notification when requested.</param>
+        void Refine(QualityOptions quality, bool delaunay, CancellationToken cancellationToken = default);
     }
 }

src/Triangle/Meshing/QualityMesher.cs

@@ -9,6 +9,7 @@ namespace TriangleNet.Meshing
 {
     using System;
     using System.Collections.Generic;
+    using System.Threading;
     using TriangleNet.Geometry;
     using TriangleNet.Meshing.Data;
     using TriangleNet.Topology;
@@ -55,7 +56,8 @@ public QualityMesher(Mesh mesh, Configuration config)
         /// </summary>
         /// <param name="quality">The quality constraints.</param>
         /// <param name="delaunay">A value indicating, whether the refined mesh should be Conforming Delaunay.</param>
-        public void Apply(QualityOptions quality, bool delaunay = false)
+        /// <param name="cancellationToken">A token that receives a cancellation notification when requested.</param>
+        public void Apply(QualityOptions quality, bool delaunay = false, CancellationToken cancellationToken = default)
         {
             // Copy quality options
             if (quality != null)
@@ -98,7 +100,7 @@ public void Apply(QualityOptions quality, bool delaunay = false)
             if (behavior.Quality && mesh.triangles.Count > 0)
             {
                 // Enforce angle and area constraints.
-                EnforceQuality();
+                EnforceQuality(cancellationToken);
             }
         }
 
@@ -841,7 +843,7 @@ private void SplitTriangle(BadTriangle badtri)
         /// <summary>
         /// Remove all the encroached subsegments and bad triangles from the triangulation.
         /// </summary>
-        private void EnforceQuality()
+        private void EnforceQuality(CancellationToken cancellationToken)
         {
             BadTriangle badtri;
 
@@ -864,6 +866,9 @@ private void EnforceQuality()
                 mesh.checkquality = true;
                 while ((queue.Count > 0) && (mesh.steinerleft != 0))
                 {
+                    // throw an OperationCanceledException if cancellation is requested
+                    cancellationToken.ThrowIfCancellationRequested();
+
                     // Fix one bad triangle by inserting a vertex at its circumcenter.
                     badtri = queue.Dequeue();
                     SplitTriangle(badtri);

src/Triangle/Smoothing/SimpleSmoother.cs

@@ -5,6 +5,7 @@
 // -----------------------------------------------------------------------
 
 using System;
+using System.Threading;
 
 namespace TriangleNet.Smoothing
 {
@@ -77,11 +78,12 @@ public SimpleSmoother(IVoronoiFactory factory, Configuration config)
         /// the previous and the current solutions. If their relative difference
         /// is not greater than the tolerance, the current solution is
         /// considered good enough already.</param>
+        /// <param name="cancellationToken">A token that receives a cancellation notification when requested.</param>
         /// <returns>The number of actual iterations performed. It is 0 if a
         /// non-positive limit is passed. Otherwise, it is always a value
         /// between 1 and the limit (inclusive).
         /// </returns>
-        public int Smooth(IMesh mesh, int limit = 10, double tol = .01)
+        public int Smooth(IMesh mesh, int limit = 10, double tol = .01, CancellationToken cancellationToken = default)
         {
             if (limit <= 0)
               return 0;
@@ -106,6 +108,9 @@ public int Smooth(IMesh mesh, int limit = 10, double tol = .01)
             int i = 0;
             while (i < limit && Math.Abs(currMax - prevMax) > tol * currMax)
             {
+                // throw an OperationCanceledException if cancellation is requested
+                cancellationToken.ThrowIfCancellationRequested();
+
                 prevMax = currMax;
                 currMax = Step(smoothedMesh, factory, predicates);