Added: ability to change fill type

src/SixLabors.Shapes/ClipperExtensions.cs

@@ -16,15 +16,16 @@ public static class ClipperExtensions
         /// </summary>
         /// <param name="shape">The shape.</param>
         /// <param name="holes">The holes.</param>
+        /// <param name="fillType">The fillType.</param>
         /// <returns>Returns a new shape with the holes cliped out out the shape.</returns>
-        public static IPath Clip(this IPath shape, IEnumerable<IPath> holes)
+        public static IPath Clip(this IPath shape, IEnumerable<IPath> holes, FillType fillType = FillType.EvenOdd)
         {
             var clipper = new Clipper();
 
             clipper.AddPath(shape, ClippingType.Subject);
             clipper.AddPaths(holes, ClippingType.Clip);
 
-            IPath[] result = clipper.GenerateClippedShapes();
+            IPath[] result = clipper.GenerateClippedShapes(fillType);
 
             return new ComplexPolygon(result);
         }

src/SixLabors.Shapes/FillType.cs

@@ -0,0 +1,31 @@
+// Copyright (c) Six Labors and contributors.
+// Licensed under the Apache License, Version 2.0.
+
+namespace SixLabors.Shapes
+{
+    /// <summary>
+    /// The fill type method used when filling a polygon.
+    /// </summary>
+    public enum FillType
+    {
+        /// <summary>
+        /// Even-Odd rule.
+        /// </summary>
+        EvenOdd = 0,
+
+        /// <summary>
+        /// Non-Zero rule.
+        /// </summary>
+        NonZero = 1,
+
+        /// <summary>
+        /// Positive rule.
+        /// </summary>
+        Positive = 2,
+
+        /// <summary>
+        /// Negative rule.
+        /// </summary>
+        Negative = 3,
+    }
+}

src/SixLabors.Shapes/PolygonClipper/Clipper.cs

@@ -40,16 +40,17 @@ public Clipper(params ClippablePath[] shapes)
         /// <summary>
         /// Executes the specified clip type.
         /// </summary>
+        /// <param name="fillType">The fillType.</param>
         /// <returns>
         /// Returns the <see cref="IPath" /> array containing the converted polygons.
         /// </returns>
-        public IPath[] GenerateClippedShapes()
+        public IPath[] GenerateClippedShapes(FillType fillType = FillType.EvenOdd)
         {
             var results = new List<PolyNode>();
 
             lock (this.syncRoot)
             {
-                this.innerClipper.Execute(ClipType.ctDifference, results);
+                this.innerClipper.Execute(ClipType.ctDifference, results, Convert(fillType));
             }
 
             var shapes = new IPath[results.Count];
@@ -153,5 +154,21 @@ internal void AddPath(ISimplePath path, ClippingType clippingType)
                 this.innerClipper.AddPath(points, type, path.IsClosed);
             }
         }
+
+        private static PolyFillType Convert(FillType type)
+        {
+            switch (type)
+            {
+                case FillType.NonZero:
+                    return PolyFillType.pftNonZero;
+                case FillType.Positive:
+                    return PolyFillType.pftPositive;
+                case FillType.Negative:
+                    return PolyFillType.pftNegative;
+                case FillType.EvenOdd:
+                default:
+                    return PolyFillType.pftEvenOdd;
+            }
+        }
     }
 }