Reduced scope of variables left and right in `OtherExtensions.Cre…

…atePolygonSet` (#313)

* Reduced scope of variables `left` and `right` in `OtherExtensions.CreatePolygonSet`

* Used `PointD` overloads in `ContainsPoint()`, had to add `explicit` operator overload to PointD

* Fixed formatting

---------

Co-authored-by: Lehonti Ramos <john@doe>

Pinta.Core/Classes/Point.cs

@@ -79,6 +79,8 @@ public readonly double Magnitude ()
 		{
 			return new PointD (a.X + b.X, a.Y + b.Y);
 		}
+
+		public static explicit operator PointD (PointI p) => new PointD (p.X, p.Y);
 	}
 
 	public record struct Size

Pinta.Core/Extensions/OtherExtensions.cs

@@ -132,22 +132,25 @@ public static IReadOnlyList<IReadOnlyList<PointI>> CreatePolygonSet (this BitMas
 				PointI last = new (start.X, start.Y + 1);
 				PointI curr = new (start.X, start.Y);
 				PointI next = curr;
-				PointI left = new ();
-				PointI right = new ();
 
 				// trace island outline
 				while (true) {
-					left.X = ((curr.X - last.X) + (curr.Y - last.Y) + 2) / 2 + curr.X - 1;
-					left.Y = ((curr.Y - last.Y) - (curr.X - last.X) + 2) / 2 + curr.Y - 1;
 
-					right.X = ((curr.X - last.X) - (curr.Y - last.Y) + 2) / 2 + curr.X - 1;
-					right.Y = ((curr.Y - last.Y) + (curr.X - last.X) + 2) / 2 + curr.Y - 1;
+					PointI left = new (
+						x: ((curr.X - last.X) + (curr.Y - last.Y) + 2) / 2 + curr.X - 1,
+						y: ((curr.Y - last.Y) - (curr.X - last.X) + 2) / 2 + curr.Y - 1
+					);
 
-					if (bounds.ContainsPoint (left.X, left.Y) && stencil[left]) {
+					PointI right = new (
+						x: ((curr.X - last.X) - (curr.Y - last.Y) + 2) / 2 + curr.X - 1,
+						y: ((curr.Y - last.Y) + (curr.X - last.X) + 2) / 2 + curr.Y - 1
+					);
+
+					if (bounds.ContainsPoint ((PointD) left) && stencil[left]) {
 						// go left
 						next.X += curr.Y - last.Y;
 						next.Y -= curr.X - last.X;
-					} else if (bounds.ContainsPoint (right.X, right.Y) && stencil[right]) {
+					} else if (bounds.ContainsPoint ((PointD) right) && stencil[right]) {
 						// go straight
 						next.X += curr.X - last.X;
 						next.Y += curr.Y - last.Y;