guitar-note-name-tutor/GuitarNoteNameTutor/Window.xaml.cs

using System;
using System.Diagnostics;
using System.Windows;
using System.Collections.Generic;
using System.Windows.Threading;
using FrequencyDetection;
using SoundCapture;

namespace GuitarNoteNameTutor
{
	/// <summary>
	/// Interaction logic for Window1.xaml
	/// </summary>
	public partial class Window
	{
		private bool IsListenning { get; set; }

		private static readonly Dictionary<int, string> HalfNoteSharpNames =
			new Dictionary<int, string>
				{
					{0, "A"},
					{1, "A\u266F"},
					{2, "B"},
					{3, "C"},
					{4, "C\u266F"},
					{5, "D"},
					{6, "D\u266F"},
					{7, "E"},
					{8, "F"},
					{9, "F\u266F"},
					{10, "G"},
					{11, "G\u266F"},
				};

		private static readonly Dictionary<int, string> HalfNoteFlatNames =
			new Dictionary<int, string>
				{
					{0, "A"},
					{1, "B\u266D"},
					{2, "B"},
					{3, "C"},
					{4, "D\u266D"},
					{5, "D"},
					{6, "E\u266D"},
					{7, "E"},
					{8, "F"},
					{9, "G\u266D"},
					{10, "G"},
					{11, "A\u266D"},
				};

		static readonly double ToneStep = Math.Pow(2, 1.0 / 12);

		private readonly Random _rand = new Random();

		FrequencyInfoSource _frequencyInfoSource;

		public Window()
		{
			InitializeComponent();

			//timer = new DispatcherTimer {Interval = TimeSpan.FromSeconds(2)};
			//timer.Tick += timer_Tick;
			//timer.Start();
		}

		private void StopListenning()
		{
			IsListenning = false;
			_frequencyInfoSource.FrequencyDetected -= FrequencyInfoSource_FrequencyDetected;
			_frequencyInfoSource.Stop();
			_frequencyInfoSource = null;
		}

		private void StartListenning(SoundCaptureDevice device)
		{
			IsListenning = true;
			_frequencyInfoSource = new SoundFrequencyInfoSource(device);
			_frequencyInfoSource.FrequencyDetected += FrequencyInfoSource_FrequencyDetected;
			_frequencyInfoSource.Listen();
		}

		void FrequencyInfoSource_FrequencyDetected(object sender, FrequencyDetectedEventArgs e)
		{
			if (!Dispatcher.CheckAccess())
			{
				Dispatcher.BeginInvoke(
					new EventHandler<FrequencyDetectedEventArgs>(FrequencyInfoSource_FrequencyDetected), sender, e);
			}
			else
			{
				if (e.Frequency <= 0)
				{
					unknownFreqLabel.Visibility = Visibility.Visible;
					frequencyLabel.Content = "?";
					return;
				}
				unknownFreqLabel.Visibility = Visibility.Hidden;

				NoteFrequency closestNote = FindClosestNote(e.Frequency);
				label.Content = HalfNoteSharpNames[closestNote.HalfStepsFromA];
				frequencyLabel.Content = string.Format("{0:0.0}Hz", e.Frequency);
			}
		}

		private class NoteFrequency
		{
			public int HalfStepsFromA;
			public double Frequency;
		}

		private static NoteFrequency FindClosestNote(double frequency)
		{
			const double aFrequency = 440.0;
			const int toneIndexOffsetToPositives = 120;

			int toneIndex = (int)Math.Round(Math.Log(frequency / aFrequency, ToneStep));
			int toneHalfStep = (toneIndexOffsetToPositives + toneIndex) % HalfNoteSharpNames.Count;
			Debug.WriteLine(string.Format("{0}, {1}", toneIndexOffsetToPositives + toneIndex, (toneIndexOffsetToPositives + toneIndex) / 12 - 7));
			NoteFrequency noteFrequency = new NoteFrequency
          	{
				HalfStepsFromA = toneHalfStep,
          		Frequency = Math.Pow(ToneStep, toneIndex)*aFrequency,
          	};

			return noteFrequency;
		}

		private DispatcherTimer timer;

		private void Window_Closing(object sender, System.ComponentModel.CancelEventArgs e)
		{
			if (IsListenning)
			{
				StopListenning();
			}
		}

		private void startButton_Click(object sender, RoutedEventArgs e)
		{
			SoundCaptureDevice device = null;
			SelectDevice form = new SelectDevice {Owner = this};
			bool? dialogResponse = form.ShowDialog();
			if (dialogResponse.HasValue && dialogResponse == true)
			{
				device = form.SelectedDevice;
			}

			if (device != null)
			{
				label.Content = string.Empty;
				StartListenning(device);
			}
		}
	}
}