Update to latest Clipper

Author: JimBobSquarePants

src/ImageSharp.Drawing/Shapes/PolygonClipper/PolygonOffsetter.cs

@@ -426,19 +426,7 @@ private void OffsetPoint(Group group, PathF path, int j, ref int k)
                 sinA = -1F;
             }
 
-            // almost straight - less than 8 degrees
-            if (cosA > .99F)
-            {
-                group.OutPath.Add(this.GetPerpendic(path[j], this.normals[k]));
-
-                // greater than 1 degree (#424)
-                if (cosA < .9998F)
-                {
-                    // (#418)
-                    group.OutPath.Add(this.GetPerpendic(path[j], this.normals[j]));
-                }
-            }
-            else if (cosA > -.99F && (sinA * this.groupDelta < 0))
+            if (cosA > -0.99F && (sinA * this.groupDelta < 0F))
             {
                 // is concave
                 group.OutPath.Add(this.GetPerpendic(path[j], this.normals[k]));
@@ -448,10 +436,6 @@ private void OffsetPoint(Group group, PathF path, int j, ref int k)
                 group.OutPath.Add(path[j]); // (#405)
                 group.OutPath.Add(this.GetPerpendic(path[j], this.normals[j]));
             }
-            else if (this.joinType == JointStyle.Round)
-            {
-                this.DoRound(group, path, j, k, MathF.Atan2(sinA, cosA));
-            }
             else if (this.joinType == JointStyle.Miter)
             {
                 // miter unless the angle is so acute the miter would exceeds ML
@@ -464,17 +448,20 @@ private void OffsetPoint(Group group, PathF path, int j, ref int k)
                     this.DoSquare(group, path, j, k);
                 }
             }
-
-            // don't bother squaring angles that deviate < ~20 degrees because
-            // squaring will be indistinguishable from mitering and just be a lot slower
-            else if (cosA > .9F)
+            else if (cosA > 0.9998F)
             {
+                // almost straight - less than 1 degree (#424)
                 this.DoMiter(group, path, j, k, cosA);
             }
-            else
+            else if (cosA > 0.99F || this.joinType == JointStyle.Square)
             {
+                // angle less than 8 degrees or a squared join
                 this.DoSquare(group, path, j, k);
             }
+            else
+            {
+                this.DoRound(group, path, j, k, MathF.Atan2(sinA, cosA));
+            }
 
             k = j;
         }