| public static FFT ( int n, bool invert, double ar, double ai ) : void | ||
| n | int | |
| invert | bool | |
| ar | double | |
| ai | double | |
| return | void | |
public override void Draw(float[] data)
{
float dx = (float)this.size.Width / (float)(data.Length / 4);
float y_offset = +20.0f;
int fftSize = data.Length / 2;
int height = this.size.Height / 2;
if (this.buffer.Length != fftSize)
{
this.buffer = new PointF[fftSize];
this.re = new double[fftSize];
this.im = new double[fftSize];
}
this.graphics.Clear(this.backgroundColor);
// L channel
{
for (int i = 0, j = 0; i < fftSize; i++, j += 2)
{
this.re[i] = data[j];
}
Array.Clear(this.im, 0, fftSize);
Utils.WindowingAsHanning(re);
Utils.FFT(fftSize, false, re, im);
for (int i = 0; i < fftSize; i++)
{
double d = 20.0 * Math.Log10(Math.Sqrt(re[i] * re[i] + im[i] * im[i]) / fftSize) + y_offset;
if (d <= -height)
{
d = -height;
}
else if (d > 0.0)
{
d = 0.0;
}
this.buffer[i] = new PointF(i * dx, -(float)d);
}
this.graphics.DrawLines(this.p, this.buffer);
}
// R channel
{
for (int i = 0, j = 1; i < fftSize; i++, j += 2)
{
this.re[i] = data[j];
}
Array.Clear(this.im, 0, fftSize);
Utils.WindowingAsHanning(re);
Utils.FFT(fftSize, false, re, im);
for (int i = 0; i < fftSize; i++)
{
double d = 20.0 * Math.Log10(Math.Sqrt(re[i] * re[i] + im[i] * im[i]) / fftSize) + y_offset;
if (d <= -height)
{
d = -height;
}
else if (d > 0.0)
{
d = 0.0;
}
this.buffer[i] = new PointF(i * dx, this.size.Height / 2 - (float)d);
}
this.graphics.DrawLines(this.p, this.buffer);
}
this.graphics.DrawLine(this.p, 0, height, this.size.Width, height);
this.graphics.Flush();
}
unsafe public override void Draw(float[] data)
{
float dx = (float)this.size.Width / (float)(data.Length / 4);
const float y_offset = +210.0f;
const float y_amplifier = 100.0f;
int fftSize = data.Length;
if (fftSize != this.re.Length)
{
this.re = new double[fftSize];
this.im = new double[fftSize];
this.spectrum = new Bitmap(1, fftSize / 4);
}
else
{
Array.Clear(this.im, 0, fftSize);
}
data.CopyTo(re, 0);
Utils.WindowingAsHanning(re);
Utils.FFT(fftSize, false, re, im);
for (int i = 0; i < fftSize / 4; i++)
{
re[i] = y_amplifier * Math.Log10(Math.Sqrt(re[i] * re[i] + im[i] * im[i]) / (fftSize * 4)) + y_offset;
if (re[i] < -255.0)
{
re[i] = -255.0;
}
else if (re[i] > 0.0)
{
re[i] = 0.0;
}
}
var bdata = this.bitmap.LockBits(new Rectangle(0, 0, this.bitmap.Width, this.bitmap.Height), ImageLockMode.ReadWrite, PixelFormat.Format32bppArgb);
{
for (byte *i = (byte *)bdata.Scan0, j = i + 4, l = i + bdata.Width * bdata.Height * 4; j < l; i++, j++)
{
*i = *j;
}
}
this.bitmap.UnlockBits(bdata);
bdata = this.spectrum.LockBits(new Rectangle(0, 0, 1, fftSize / 4), ImageLockMode.ReadWrite, PixelFormat.Format32bppArgb);
{
int j = 0;
for (byte *i = (byte *)bdata.Scan0, l = i + bdata.Height * 4; i < l; j++)
{
byte b = (byte)(255.0 + re[j]);
* i++ = b;
* i++ = b;
* i++ = b;
* i++ = 255;
}
}
this.spectrum.UnlockBits(bdata);
this.graphics.DrawImage(this.spectrum, this.size.Width - 1, this.size.Height - 1, 1, -this.size.Height);
this.graphics.Flush();
}
