added border to initial image used in final image calculation

SDFMapCreator/Program.cs

@@ -116,7 +116,7 @@ public static class Program {
         
         for (var x = 0; x < width; x++)
             for (var y = 0; y < height; y++)
-                finalImage[x, y] = new(Images[0].Pixels[x, y].X);
+                finalImage[x, y] = new(ImageMasks[0].Mask[x, y].X != 0 || ImageMasks[0].Mask[x, y].Y > 0 ? MAX : MIN);
         
         for (var i = 0; i < Gradients.Count; i++) {
             var mask = ImageMasks[i + 1];