Merge pull request #405 from chuongmep/methodcenter

Add Get Centroid method

src/GShark.Test.XUnit/Geometry/Point3Tests.cs

@@ -1,7 +1,6 @@
-using System.Security.Cryptography.X509Certificates;
+using System.Collections.Generic;
 using FluentAssertions;
 using GShark.Geometry;
-using haxe.ds;
 using Xunit;
 using Xunit.Abstractions;
 
@@ -126,6 +125,22 @@ public void It_Divides_A_Point3d_By_A_Number()
             // Assert
             divisionResult.Equals(expectedPoint).Should().Be(true);
         }
+
+        [Fact]
+        public void It_Returns_Centroid_Of_Collection_Points()
+        {
+            // Arrange
+            Point3 p1 = new Point3(1, 2, 3);
+            Point3 p2 = new Point3(4, 5, 6);
+            Point3 p3 = new Point3(7, 8, 9);
+            Point3 p4 = new Point3(10, 11, 12);
+            List<Point3> point3s = new List<Point3> { p1, p2, p3, p4 };
+            //Act
+            Point3 centroid = Point3.Centroid(point3s);
+            Point3 expectedCentroid = new Point3(5.5, 6.5, 7.5);
+            // Assert
+            centroid.Equals(expectedCentroid).Should().Be(true);
+        }
 
         [Fact]
         public void It_Returns_True_If_Two_Points_Are_Equal()

src/GShark/Geometry/Point3.cs

@@ -1,6 +1,7 @@
 using GShark.Core;
 using System;
 using System.Collections.Generic;
+using System.Linq;
 
 namespace GShark.Geometry
 {
@@ -496,7 +497,20 @@ public static Point3 PointBetween(Point3 p1, Point3 p2)
         {
             return Interpolate(p1, p2, 0.5);
         }
-
+
+        /// <summary>
+        /// Calculate the centroid of an arbitrary collection of points
+        /// </summary>
+        /// <param name="points">A collection of points.</param>
+        /// <returns>The centroid of the points</returns>
+        public static Point3 Centroid(IEnumerable<Point3> points)
+        {
+            IEnumerable<Point3> enumerable = points as Point3[] ?? points.ToArray();
+            return new Point3(
+                enumerable.Average(point => point.X),
+                enumerable.Average(point => point.Y),
+                enumerable.Average(point => point.Z));
+        }
         /// <summary>
         /// Constructs the string representation for the current point.
         /// </summary>