SoundtrackControl.cs

namespace ToneGenerator
{
	public partial class SoundtrackControl : UserControl
	{
		public SoundtrackControl() : this(true) { }

		public SoundtrackControl(bool play)
		{
			InitializeComponent();

			frequencyNumeric.Maximum = SineWaveProvider.SAMPLE_RATE / 2M;

			Amplitude = 1f;
			Soundtrack.Frequency = (float)frequencyNumeric.Value;
			Soundtrack.Left = leftCheckBox.Checked = play;
			Soundtrack.Right = rightCheckBox.Checked = play;
		}

		public Soundtrack Soundtrack { get; private set; } = new Soundtrack();

		public float Amplitude
		{
			get => Soundtrack.Amplitude;
			set
			{
				if (value < 0.0f)
					value = 0.0f;
				if (value != Amplitude)
				{
					volumeLabel.Text = "Amplitude: " + value;
					Soundtrack.Amplitude = value;
					dBVolumeSlider.Volume = value;
				}
			}
		}

		public void SetMinimumVolume(float minVolume)
		{
			dBVolumeSlider.MinimumDB = minVolume;
		}

		internal void SetMaximumValue(float maxVolume)
		{
			dBVolumeSlider.MaximumDB = maxVolume;
		}

		public void SetLeft(bool value)
		{
			Soundtrack.Left = leftCheckBox.Checked = value;
		}

		public void SetRight(bool value)
		{
			Soundtrack.Right = rightCheckBox.Checked = value;
		}

		public void MultiplyFrequency(double factor)
		{
			var value = frequencyNumeric.Value * (decimal)factor;
			if (value < frequencyNumeric.Minimum)
				value = frequencyNumeric.Minimum;
			if (value > frequencyNumeric.Maximum)
				value = frequencyNumeric.Maximum;
			frequencyNumeric.Value = value;
		}

		/// <summary>
		/// Processes shortcut keys for frequency and volume controls.
		/// </summary>
		/// <param name="msg">A <see cref="Message"/>, passed by reference, that represents the Win32 message to process.</param>
		/// <param name="keyData">One of the <see cref="Keys"/> values that represents the key to process.</param>
		/// <returns>true if the keystroke was processed and consumed by the control; otherwise, false to allow further processing.</returns>
		protected override bool ProcessCmdKey(ref Message msg, Keys keyData)
		{
			if (keyData == Keys.Add || keyData == Keys.Subtract)
			{
				// Change dbVolume by ±1 dB.
				double logVolume = Math.Log10(dBVolumeSlider.Volume);
				if (keyData == Keys.Subtract)
					logVolume -= 0.05f;
				else if (keyData == Keys.Add)
					logVolume += 0.05f;
				Amplitude = (float)Math.Pow(10, logVolume);
				return true;
			}

			switch (keyData)
			{
				case Keys.OemMinus:
					MultiplyFrequency(1.0 / GetHalfFrequencyIncrement());
					return true;
				case Keys.Oemplus:
					MultiplyFrequency(GetHalfFrequencyIncrement());
					return true;
				case Keys.Oemcomma:
					MultiplyFrequency(1.0 / GetFrequencyIncrement());
					return true;
				case Keys.OemPeriod:
					MultiplyFrequency(GetFrequencyIncrement());
					return true;
				case Keys.OemSemicolon:
					MultiplyFrequency(1.0 / GetDoubleFrequencyIncrement());
					return true;
				case Keys.OemQuotes:
					MultiplyFrequency(GetDoubleFrequencyIncrement());
					return true;
				case Keys.OemOpenBrackets:
					MultiplyFrequency(0.5);
					return true;
				case Keys.OemCloseBrackets:
					MultiplyFrequency(2);
					return true;
				default:
					return base.ProcessCmdKey(ref msg, keyData);
			}

		}

		private double GetFrequencyIncrement()
		{
			return ParentForm is not Form1 parent ? Math.Pow(2.0, 1.0 / 12) : parent.FrequencyIncrement;
		}

		private double GetDoubleFrequencyIncrement()
		{
			var x = GetFrequencyIncrement();
			return x * x;
		}

		private double GetHalfFrequencyIncrement()
		{
			return Math.Sqrt(GetFrequencyIncrement());
		}

		private void DBVolumeSlider_VolumeChanged(object sender, EventArgs e)
		{
			Amplitude = dBVolumeSlider.Volume;
		}

		private void FrequencyNumeric_ValueChanged(object sender, EventArgs e)
		{
			Soundtrack.Frequency = (float)frequencyNumeric.Value;
		}

		private void ChangeFrequencyButtons_Click(object sender, EventArgs e)
		{
			if (sender == minusButton)
				MultiplyFrequency(1.0 / GetHalfFrequencyIncrement());
			else if (sender == plusButton)
				MultiplyFrequency(GetHalfFrequencyIncrement());
			else if (sender == prevNoteButton)
				MultiplyFrequency(1.0 / GetFrequencyIncrement());
			else if (sender == nextNoteButton)
				MultiplyFrequency(GetFrequencyIncrement());
			else if (sender == minus2Button)
				MultiplyFrequency(1.0 / GetDoubleFrequencyIncrement());
			else if (sender == plus2Button)
				MultiplyFrequency(GetDoubleFrequencyIncrement());
			else if (sender == prevOctaveButton)
				MultiplyFrequency(0.5);
			else if (sender == nextOctaveButton)
				MultiplyFrequency(2.0);
		}

		private void LeftCheckBox_CheckedChanged(object sender, EventArgs e)
		{
			SetLeft(leftCheckBox.Checked);
		}

		private void RightCheckBox_CheckedChanged(object sender, EventArgs e)
		{
			SetRight(rightCheckBox.Checked);
		}
	}
}