Move TrackLength to cached property

MusicBoxConverter/MusicBoxScoreGenerator.cs

@@ -16,6 +16,14 @@ namespace MusicBoxConverter
 
 		public int holeSize { get; set; } = 5;
 
+		private int trackLength;
+		public int TrackLength {
+			get {
+				if(trackLength == null)
+					trackLength = (int)AllNotes().Max((Note arg) => arg.Time);
+				return trackLength;
+			}
+		}
 
 		MidiFile midiFile;
 		
@@ -27,7 +35,12 @@ namespace MusicBoxConverter
 		public void Output(string destinationFilename)
 		{
 			SvgWriter svg = new SvgWriter(destinationFilename);
-			svg.WriteRectangle(offset, new Vector2(TrackLength(), 128).Multiply(scaleFactor));
+			svg.WriteRectangle(offset, new Vector2(TrackLength, 128).Multiply(scaleFactor));
+			for(int i = 0; i < 255; i += 5)
+			{
+				Vector2 start = offset.Add(new Vector2(0, i));
+				svg.WriteLine(start, start.Add(new Vector2(TrackLength, 0)));
+			}
 
 			foreach(Note note in AllNotes())
 			{
@@ -44,11 +57,6 @@ namespace MusicBoxConverter
 			svg.Complete();
 		}
 
-		public int TrackLength()
-		{
-			return (int)AllNotes().Max((Note arg) => arg.Time);
-		}
-
 		public IEnumerable<Note> AllNotes()
 		{
 			foreach(TrackChunk chunk in midiFile.Chunks.OfType<TrackChunk>())

MusicBoxConverter/SvgWriter.cs

@@ -30,6 +30,11 @@ namespace MusicBoxConverter
 			xml.Close();
 		}
 
+		public void WriteLine(Vector2 start, Vector2 end, string strokeStyle = "darkgreen", int strokeWidth = 3)
+		{
+			WritePath($"M {start.X} {start.Y} L {end.X} {end.Y}", strokeStyle, strokeWidth);
+		}
+
 		public void WritePath(string pathData, string strokeStyle = "green", int strokeWidth = 3)
 		{
 			xml.WriteStartElement("path");