add circle hatch example file

Author: thaiguer

src/ACadSharp.Examples/Entities/CircleHatchExample.cs

@@ -0,0 +1,50 @@
+using ACadSharp.Entities;
+using CSMath;
+using System.Collections.Generic;
+
+namespace ACadSharp.Examples.Entities
+{
+	internal class CircleHatchExample
+	{
+		public static Hatch CreateCircleHatch(XY center, double radius)
+		{
+			Hatch hatch = new Hatch();
+			hatch.IsSolid = true;
+			hatch.SeedPoints.Add(new XY());
+			hatch.Color = new Color(15);
+
+			List<Hatch.BoundaryPath.Line> edges = new List<Hatch.BoundaryPath.Line>();
+
+			Hatch.BoundaryPath.Arc arc = new();
+			arc.Center = center;
+			arc.CounterClockWise = true;
+			arc.Radius = radius;
+			arc.StartAngle = 0;
+			arc.EndAngle = MathHelper.TwoPI;
+
+			Hatch.BoundaryPath path = new Hatch.BoundaryPath();
+			path.Edges.Add(arc);
+			hatch.Paths.Add(path);
+
+			return hatch;
+		}
+
+		/// <summary>
+		/// Create some circle hatches and add them to the model
+		/// </summary>
+		public static void AddInsertIntoModel()
+		{
+			var hatches = new List<Hatch>();
+			hatches.Add(CreateCircleHatch(new XY(0, 15), 10));
+			hatches.Add(CreateCircleHatch(new XY(30, 12), 5));
+			hatches.Add(CreateCircleHatch(new XY(50, 50), 25.3));
+			hatches.Add(CreateCircleHatch(new XY(100, 50), 5));
+			hatches.Add(CreateCircleHatch(new XY(-30, 10), 30));
+
+			CadDocument doc = new CadDocument();
+			doc.ModelSpace.Entities.AddRange(hatches);
+
+			//Once the file is saved you will have some circular hatches added to its modelspace
+		}
+	}
+}