Port AddPolygon -> WritePolygon from the FloatingIslands, but we should consider creating a NuGet package.

MusicBoxConverter/MusicBoxScoreGenerator.cs

@@ -69,8 +69,9 @@ namespace MusicBoxConverter
 			SvgWriter svg = new SvgWriter(
 				destinationFilename,
 				$"{size.X}mm", $"{size.Y}mm"
-			);
+			) {
-			svg.UnitSuffix = "mm";
+				UnitSuffix = "mm"
+			};
 
 			// Draw the note lines
 			for(float i = 0; i < area.Y; i += ScaleFactor.Y) {

MusicBoxConverter/SvgWriter.cs

@@ -1,5 +1,6 @@
 using System;
 using System.IO;
+using System.Linq;
 using System.Xml;
 using SBRL.Utilities;
 
@@ -17,6 +18,9 @@ namespace MusicBoxConverter
 		}
 	}
 
+	/// <summary>
+	/// TODO: Replace this with the (much) better version from the FloatingIslands
+	/// </summary>
 	public class SvgWriter
 	{
 		public XmlWriter xml;
@@ -106,5 +110,18 @@ namespace MusicBoxConverter
 			xml.WriteAttributeString("fill", fillStyle);
 			xml.WriteEndElement();
 		}
+		/// <summary>
+		/// Adds a solid n-sided polygon to the image.
+		/// </summary>
+		/// <param name="fillStyle">The colour to fill the polygon with.</param>
+		/// <param name="points">The co-ordinates that make up the polygon.</param>
+		public void WritePolygon(string fillStyle, params Vector2[] points)
+		{
+			xml.WriteStartElement("polygon");
+			xml.WriteAttributeString("fill", fillStyle);
+			string pointsSpec = string.Join(" ", points.Select((Vector2 point) => $"{point.X},{point.Y}"));
+			xml.WriteAttributeString("points", pointsSpec);
+			xml.WriteEndElement();
+		}
 	}
 }