// TODO: remove this )))
private void featuresListView_SelectedIndexChanged(object sender, EventArgs e)
{
if (featuresListView.SelectedItems.Count == 0)
{
return;
}
var pos = featuresListView.SelectedIndices[0];
var fft = new Fft(512);
var spectrum = fft.PowerSpectrum(_signal[pos * _hopSize, pos * _hopSize + _frameSize]).Samples;
var peaks = new int[10];
var freqs = new float[10];
Harmonic.Peaks(spectrum, peaks, freqs, _signal.SamplingRate);
peaksListBox.Items.Clear();
for (var p = 0; p < peaks.Length; p++)
{
peaksListBox.Items.Add($"peak #{p+1,-2} : {freqs[p],-7} Hz");
}
_spectrumImage = new Bitmap(512, spectrumPictureBox.Height);
var g = Graphics.FromImage(_spectrumImage);
g.Clear(Color.White);
var pen = new Pen(ForeColor);
var redpen = new Pen(Color.Red, 2);
var i = 1;
var Stride = 4;
var PaddingX = 5;
var PaddingY = 5;
var x = PaddingX + Stride;
var min = spectrum.Min();
var max = spectrum.Max();
var height = _spectrumImage.Height;
var gain = max - min < 1e-6 ? 1 : (height - 2 * PaddingY) / (max - min);
var offset = (int)(height - PaddingY + min * gain);
for (; i < spectrum.Length; i++)
{
g.DrawLine(pen, x - Stride, -spectrum[i - 1] * gain + offset,
x, -spectrum[i] * gain + offset);
x += Stride;
}
for (i = 0; i < peaks.Length; i++)
{
g.DrawLine(redpen, PaddingX + peaks[i] * Stride, PaddingY + offset,
PaddingX + peaks[i] * Stride, -PaddingY - spectrum[peaks[i]] * gain + offset);
}
pen.Dispose();
redpen.Dispose();
g.Dispose();
spectrumPictureBox.Image = _spectrumImage;
}
