fix demo

samples/AvatarWithRoundedCorner/Program.cs

@@ -8,57 +8,69 @@ namespace AvatarWithRoundedCorner
     using SixLabors.Primitives;
     using SixLabors.Shapes;
 
-    class Program
+    static class Program
     {
         static void Main(string[] args)
         {
             System.IO.Directory.CreateDirectory("output");
+            using (var img = Image.Load("fb.jpg"))
+            {
+                // as generate returns a new IImage make sure we dispose of it
+                using (Image<Rgba32> dest = img.Generate(x => x.ConvertToAvatar(new Size(200, 200), 20)))
+                {
+                    dest.Save("output/fb.png");
+                }
+
+                using (Image<Rgba32> destRound = img.Generate(x => x.ConvertToAvatar(new Size(200, 200), 100)))
+                {
+                    destRound.Save("output/fb-round.png");
+                }
 
-            GenerateAvatar("fb.jpg", "output/fb.png", new Size(200, 200), 20);
-            GenerateAvatar("fb.jpg", "output/fb-round.png", new Size(200, 200), 100);
-            GenerateAvatar("fb.jpg", "output/fb-rounder.png", new Size(200, 200), 150);
+                using (Image<Rgba32> destRound = img.Generate(x => x.ConvertToAvatar(new Size(200, 200), 150)))
+                {
+                    destRound.Save("output/fb-rounder.png");
+                }
+                
+                // the original `img` object has not been altered at all.
+            }
         }
 
-        private static void GenerateAvatar(string source, string destination, Size size, float cornerRadius)
+        // lets create our custom image mutating pipeline
+        private static IImageOperations<Rgba32> ConvertToAvatar(this IImageOperations<Rgba32> operations, Size size, float cornerRadius)
         {
-            using (var image = Image.Load(source))
+            return operations.Resize(new ImageSharp.Processing.ResizeOptions
             {
-                image.Mutate(x => x
-                    .Resize(new ImageSharp.Processing.ResizeOptions
-                    {
-                        Size = size,
-                        Mode = ImageSharp.Processing.ResizeMode.Crop
-                    })
-                    .Run(i=>ApplyRoundedCourners(i, cornerRadius)));
-
-                image.Save(destination);
-            }
+                Size = size,
+                Mode = ImageSharp.Processing.ResizeMode.Crop
+            }).Run(i => ApplyRoundedCourners(i, cornerRadius));
         }
 
+        // the combination of `IImageOperations.Run()` + this could be replaced with an `IImageProcessor`
         public static void ApplyRoundedCourners(Image<Rgba32> img, float cornerRadius)
         {
             var corners = BuildCorners(img.Width, img.Height, cornerRadius);
-            // now we have our corners time to draw them
+
+            // mutating in here as we already have a cloned original
             img.Mutate(x => x.Fill(Rgba32.Transparent, corners, new GraphicsOptions(true)
             {
                 BlenderMode = ImageSharp.PixelFormats.PixelBlenderMode.Src // enforces that any part of this shape that has color is punched out of the background
             }));
         }
 
-        public static  IPathCollection BuildCorners(int imageWidth, int imageHeight, float cornerRadius)
+        public static IPathCollection BuildCorners(int imageWidth, int imageHeight, float cornerRadius)
         {
             // first create a square
             var rect = new SixLabors.Shapes.RectangularePolygon(-0.5f, -0.5f, cornerRadius, cornerRadius);
 
             // then cut out of the square a circle so we are left with a corner
-            var cornerToptLeft = rect.Clip(new SixLabors.Shapes.EllipsePolygon(cornerRadius-0.5f, cornerRadius - 0.5f, cornerRadius));
+            var cornerToptLeft = rect.Clip(new SixLabors.Shapes.EllipsePolygon(cornerRadius - 0.5f, cornerRadius - 0.5f, cornerRadius));
 
             // corner is now a corner shape positions top left
             //lets make 3 more positioned correctly, we cando that by translating the orgional artound the center of the image
             var center = new Vector2(imageWidth / 2, imageHeight / 2);
             var angle = Math.PI / 2f;
 
-            float rightPos = imageWidth - cornerToptLeft.Bounds.Width  +1;
+            float rightPos = imageWidth - cornerToptLeft.Bounds.Width + 1;
             float bottomPos = imageHeight - cornerToptLeft.Bounds.Height + 1;
 
             // move it across the widthof the image - the width of the shape