public DrawHandler(WindowGraphics windowGraphics)
{
this.windowGraphics = windowGraphics;
windowGraphics.TryUpdateGraphics();
DrawingContext = windowGraphics.drawingVisual.RenderOpen();
var transformGroup = new TransformGroup();
transformGroup.Children.Add(new ScaleTransform(1, -1));
transformGroup.Children.Add(new TranslateTransform(0, windowGraphics.height));
transformGroup.Freeze();
DrawingContext.PushTransform(transformGroup);
}
/// <summary>
/// 绘制波形
/// </summary>
/// <param name="win"></param>
/// <param name="waveQueueData"></param>
/// <param name="polylineStyle"></param>
/// <param name="id">区分线程，调试用</param>
static void DrawWave(Window win, FixedQueueArray <float> waveQueueData, bool polylineStyle, int id = 0)
{
var lineColor = Color.FromRgb(17, 125, 187);
var lineBrush = new SolidColorBrush(lineColor);
lineBrush.Freeze();
var pen = new Pen(lineBrush, 1);
pen.Freeze();
// WindowGraphics 这是一个可以跨进程绘制窗体的类
// 使用 WPF 中的 DrawingContext 进行绘制
var wg = new WindowGraphics(win);
while (true)
{
Task.Delay(20).Wait();
using (var drawCtx = wg.OpenDraw()) {
Span <float> waveData = new float[(int)drawCtx.Size.Width];
waveQueueData.Read(waveData);
drawCtx.DrawingContext.DrawRectangle(Brushes.White, null, new Rect(drawCtx.Size));
DrawBorder(drawCtx);
var h2 = drawCtx.Size.Height / 2;
Point[] points;
if (polylineStyle)
{
const int step = 10;
points = new Point[waveData.Length / step + 1];
for (int i = 0; i < points.Length; i++)
{
double sum = 0;
int count = 0;
for (int j = 0; j < step; j++)
{
if (i * step + j >= waveData.Length)
{
break;
}
sum += waveData[i * step + j];
count++;
}
var avg = count > 0 ? sum / count : 0;
points[i] = new Point(i * step, h2 + avg * h2);
}
points[points.Length - 1].X = drawCtx.Size.Width;
}
else
{
points = new Point[waveData.Length];
for (int i = 0; i < waveData.Length; i++)
{
double y = waveData[i] * h2;
points[i] = new Point(i, h2 + y);
}
}
var geometry = new StreamGeometry();
using (var geometryCtx = geometry.Open()) {
geometryCtx.BeginFigure(points[0], false, false);
geometryCtx.PolyLineTo(points, true, true);
}
geometry.Freeze();
drawCtx.DrawingContext.DrawGeometry(null, pen, geometry);
}
}
}
/// <summary>
/// 绘制频谱（FFT算法用的是FFTW库）
/// </summary>
/// <param name="win"></param>
/// <param name="nextData"></param>
/// <param name="sampleRate"></param>
/// <param name="polylineStyle"></param>
/// <param name="id">区分线程，调试用</param>
static void DrawSpectrum(Window win, float[] nextData, int sampleRate, bool polylineStyle, int id = 0)
{
double * inBuff = (double *)fftw.alloc_complex((IntPtr)FFTSize);
double * outBuff = (double *)fftw.alloc_complex((IntPtr)FFTSize);
IntPtr fft = fftw.dft_1d(FFTSize, (IntPtr)inBuff, (IntPtr)outBuff, fftw_direction.Forward, fftw_flags.Estimate);
Span <double> tempBuff = stackalloc double[FFTSize];
var cutLength = FFTTools.CutFrequencyLength(FFTSize, MinimumFrequency, MaximumFrequency, sampleRate, FFTComplexCount);
Span <double> cutData = tempBuff.Slice(0, cutLength);
DSP.Window fftWindow = new DSP.BlackmanNuttallWindow(FFTSize);
ILogarithm log = new DSP.Decade();
var lineBrush = new SolidColorBrush(Color.FromRgb(17, 125, 187));
var pen = new Pen(lineBrush, 1);
var backBrush = new SolidColorBrush(Color.FromRgb(241, 246, 250));
lineBrush.Freeze();
pen.Freeze();
backBrush.Freeze();
Point[] drawPoints = null;
Span <double> logData = null;
var wg = new WindowGraphics(win);
while (true)
{
Task.Delay(20).Wait();
using (var drawCtx = wg.OpenDraw()) {
lock (fftLock) {
for (int i = 0; i < nextData.Length; i++)
{
tempBuff[i] = nextData[i];
}
}
// 加窗
fftWindow?.Apply(tempBuff, tempBuff);
for (int i = 0; i < tempBuff.Length; i++)
{
inBuff[2 * i + 0] = tempBuff[i];
inBuff[2 * i + 1] = 0;
}
// 执行FFT
fftw.execute(fft);
if (logData == null || logData.Length != (int)drawCtx.Size.Width)
{
logData = new double[(int)drawCtx.Size.Width];
}
double h = drawCtx.Size.Height;
// FFT复数结果取模
FFTTools.Abs(FFTSize, new ReadOnlySpan <Complex>(outBuff, FFTSize), tempBuff, true, fftWindow);
// 保留感兴趣的频率区域
FFTTools.CutFrequency(FFTSize, MinimumFrequency, MaximumFrequency, sampleRate, tempBuff, cutData);
// 频率以对数方式显示
FFTTools.Logarithm(cutData, MinimumFrequency, MaximumFrequency, logData, log);
// 振幅以分贝方式显示
FFTTools.ToDB(logData, MaxDB);
// 因为上面的结果在区间[0,1]，所以乘以窗体高度h，才能画满整个窗体
FFTTools.Scale(logData, h);
if (polylineStyle)
{
const int step = 10;
var points = new Point[logData.Length / step + 1];
for (int i = 0; i < points.Length; i++)
{
double max = 0;
for (int j = 0; j < step; j++)
{
if (i * step + j >= logData.Length)
{
break;
}
max = Math.Max(logData[i * step + j], max);
}
points[i] = new Point(i * step, h - max);
}
points[points.Length - 1].X = drawCtx.Size.Width;
drawPoints = new Point[points.Length + 2];
points.AsSpan().CopyTo(drawPoints);
}
else
{
drawPoints = new Point[logData.Length + 2];
for (int i = 0; i < logData.Length; i++)
{
drawPoints[i] = new Point(i, h - logData[i]);
}
}
drawPoints[drawPoints.Length - 2] = new Point(drawCtx.Size.Width, drawCtx.Size.Height);
drawPoints[drawPoints.Length - 1] = new Point(0, drawCtx.Size.Height);
var geometry = new StreamGeometry();
using (var geometryCtx = geometry.Open()) {
geometryCtx.BeginFigure(drawPoints[0], true, true);
geometryCtx.PolyLineTo(drawPoints, true, true);
}
geometry.Freeze();
drawCtx.DrawingContext.DrawRectangle(Brushes.White, null, new Rect(drawCtx.Size));
drawCtx.DrawingContext.DrawGeometry(backBrush, null, geometry);
DrawBorder(drawCtx);
drawCtx.DrawingContext.DrawGeometry(null, pen, geometry);
}
}
}
