fixes some corner clipping issues

src/ImageSharp.Drawing.Paths/ShapePath.cs

@@ -101,8 +101,8 @@ namespace ImageSharp.Drawing
         /// <inheritdoc/>
         public override int ScanY(int y, float[] buffer, int length, int offset)
         {
-            Vector2 start = new Vector2(float.MinValue, y);
-            Vector2 end = new Vector2(float.MaxValue, y);
+            Vector2 start = new Vector2(this.Bounds.Left - 1, y);
+            Vector2 end = new Vector2(this.Bounds.Right + 1, y);
             Vector2[] innerbuffer = ArrayPool<Vector2>.Shared.Rent(length);
             try
             {

src/ImageSharp.Drawing.Paths/ShapeRegion.cs

@@ -81,8 +81,8 @@ namespace ImageSharp.Drawing
         /// <inheritdoc/>
         public override int ScanY(int y, float[] buffer, int length, int offset)
         {
-            Vector2 start = new Vector2(float.MinValue, y);
-            Vector2 end = new Vector2(float.MaxValue, y);
+            Vector2 start = new Vector2(this.Bounds.Left - 1, y);
+            Vector2 end = new Vector2(this.Bounds.Right + 1, y);
             Vector2[] innerbuffer = ArrayPool<Vector2>.Shared.Rent(length);
             try
             {

src/ImageSharp.Drawing.Paths/project.json

@@ -44,7 +44,7 @@
     "ImageSharp.Drawing": {
       "target": "project"
     },
-    "SixLabors.Shapes": "0.1.0-alpha0002",
+    "SixLabors.Shapes": "0.1.0-alpha0003",
     "StyleCop.Analyzers": {
       "version": "1.0.0",
       "type": "build"

src/ImageSharp.Drawing/Processors/FillRegionProcessor.cs

@@ -57,7 +57,7 @@ namespace ImageSharp.Drawing.Processors
         /// <inheritdoc/>
         protected override void OnApply(ImageBase<TColor> source, Rectangle sourceRectangle)
         {
-            Rectangle rect = RectangleF.Ceiling(this.Region.Bounds); // rounds the points out away from the center
+            Rectangle rect = this.Region.Bounds;
 
             int polyStartY = sourceRectangle.Y - DrawPadding;
             int polyEndY = sourceRectangle.Bottom + DrawPadding;
@@ -102,6 +102,13 @@ namespace ImageSharp.Drawing.Processors
                             return;
                         }
 
+                        if (pointsFound == 1 && maxIntersections > 1)
+                        {
+                            // we must have clipped a corner lets just duplicate it into point 2 and continue :)
+                            buffer[1] = buffer[0];
+                            pointsFound++;
+                        }
+
                         if (pointsFound % 2 == 1)
                         {
                             // we seem to have just clipped a corner lets just skip it
@@ -246,6 +253,13 @@ namespace ImageSharp.Drawing.Processors
                                 return;
                             }
 
+                            if (pointsFound == 1 && maxIntersections > 1)
+                            {
+                                // we must have clipped a corner lets just duplicate it into point 2 and continue :)
+                                buffer[1] = buffer[0];
+                                pointsFound++;
+                            }
+
                             if (pointsFound % 2 == 1)
                             {
                                 // we seem to have just clipped a corner lets just skip it

tests/ImageSharp.Tests/Drawing/SolidPolygonTests.cs

@@ -13,6 +13,7 @@ namespace ImageSharp.Tests.Drawing
     using System.Numerics;
     using Xunit;
     using ImageSharp.Drawing.Brushes;
+    using SixLabors.Shapes;
 
     public class SolidPolygonTests : FileTestBase
     {
@@ -151,7 +152,7 @@ namespace ImageSharp.Tests.Drawing
                 {
                     image
                         .BackgroundColor(Color.Blue)
-                        .Fill(Color.HotPink, new SixLabors.Shapes.Rectangle(10,10, 190, 140))
+                        .Fill(Color.HotPink, new SixLabors.Shapes.Rectangle(10, 10, 190, 140))
                          .Save(output);
                 }
 
@@ -169,5 +170,78 @@ namespace ImageSharp.Tests.Drawing
                 }
             }
         }
+
+        [Fact]
+        public void ImageShouldBeOverlayedByFilledTriangle()
+        {
+            string path = this.CreateOutputDirectory("Drawing", "FilledPolygons");
+
+            using (Image image = new Image(100, 100))
+            {
+                using (FileStream output = File.OpenWrite($"{path}/Triangle.png"))
+                {
+                    image
+                        .BackgroundColor(Color.Blue)
+                        .Fill(Color.HotPink, new RegularPolygon(50, 50, 3, 30))
+                         .Save(output);
+                }
+
+                using (PixelAccessor<Color> sourcePixels = image.Lock())
+                {
+                    Assert.Equal(Color.HotPink, sourcePixels[25, 35]);
+
+                    Assert.Equal(Color.HotPink, sourcePixels[50, 79]);
+
+                    Assert.Equal(Color.HotPink, sourcePixels[75, 35]);
+
+                    Assert.Equal(Color.HotPink, sourcePixels[50, 50]);
+
+                    Assert.Equal(Color.Blue, sourcePixels[2, 2]);
+
+                    Assert.Equal(Color.Blue, sourcePixels[28, 60]);
+
+                    Assert.Equal(Color.Blue, sourcePixels[67, 67]);
+                }
+            }
+        }
+
+        [Fact]
+        public void ImageShouldBeOverlayedByFilledSeptagon()
+        {
+            string path = this.CreateOutputDirectory("Drawing", "FilledPolygons");
+
+            var config = Configuration.CreateDefaultInstance();
+            config.ParallelOptions.MaxDegreeOfParallelism = 1;
+            using (Image image = new Image(100, 100, config))
+            {
+                using (FileStream output = File.OpenWrite($"{path}/Septagon.png"))
+                {
+                    image
+                        .BackgroundColor(Color.Blue)
+                        .Fill(Color.HotPink, new RegularPolygon(50, 50, 7, 30, -(float)Math.PI))
+                         .Save(output);
+                }
+            }
+        }
+
+        [Fact]
+        public void ImageShouldBeOverlayedByFilledEllipse()
+        {
+            string path = this.CreateOutputDirectory("Drawing", "FilledPolygons");
+
+            var config = Configuration.CreateDefaultInstance();
+            config.ParallelOptions.MaxDegreeOfParallelism = 1;
+            using (Image image = new Image(100, 100, config))
+            {
+                using (FileStream output = File.OpenWrite($"{path}/ellipse.png"))
+                {
+                    image
+                        .BackgroundColor(Color.Blue)
+                        .Fill(Color.HotPink, new Ellipse(50, 50, 30, 50)
+                                                .Rotate((float)(Math.PI / 3)))
+                         .Save(output);
+                }
+            }
+        }
     }
 }