support roll display

swharden · swharden · commit 692ea3b937f0 · 2020-06-06T17:18:22.000-04:00
diff --git a/src/Spectrogram.MicrophoneDemo/Form1.Designer.cs b/src/Spectrogram.MicrophoneDemo/Form1.Designer.cs
diff --git a/src/Spectrogram.MicrophoneDemo/Form1.cs b/src/Spectrogram.MicrophoneDemo/Form1.cs
@@ -72,13 +72,26 @@ private void timer1_Tick(object sender, EventArgs e)
                 Stopwatch sw = Stopwatch.StartNew();
                 spec.Process();
                 spec.TrimWidth(pictureBox1.Width);
-                Bitmap bmp = spec.GetBitmap(multiplier, cbDecibels.Checked);
+                Bitmap bmp = spec.GetBitmap(multiplier, cbDecibels.Checked, cbRoll.Checked);
+                Bitmap bmp2 = new Bitmap(spec.Width, spec.Height, System.Drawing.Imaging.PixelFormat.Format32bppPArgb);
+                using (var gfx = Graphics.FromImage(bmp2))
+                using (var pen = new Pen(Color.White))
+                {
+                    gfx.DrawImage(bmp, 0, 0);
+                    if (cbRoll.Checked)
+                    {
+                        int x = spec.FftsProcessed % pictureBox1.Width - 1;
+                        gfx.DrawLine(pen, x, 0, x, pictureBox1.Height);
+                    }
+                }
+                bmp.Dispose();
+
                 sw.Stop();
                 pictureBox1.Image?.Dispose();
-                pictureBox1.Image = bmp;
+                pictureBox1.Image = bmp2;
                 lblStatus3.Text = $"Render time: {sw.ElapsedMilliseconds:D2} ms";
             }
-            
+
             lblStatus1.Text = $"Time: {listener.TotalTimeSec:N3} sec";
             lblStatus2.Text = $"FFTs processed: {spec.FftsProcessed:N0}";
             pbAmplitude.Value = (int)(listener.AmplitudeFrac * pbAmplitude.Maximum);
diff --git a/src/Spectrogram/Spectrogram.cs b/src/Spectrogram/Spectrogram.cs
@@ -78,17 +78,16 @@ public void Process()
                 newFfts[newFftIndex] = new double[settings.Height];
                 for (int i = 0; i < settings.Height; i++)
                     newFfts[newFftIndex][i] = buffer[settings.FftIndex1 + i].Magnitude / settings.FftSize;
-
-                FftsProcessed += 1;
             });
 
             foreach (var newFft in newFfts)
                 ffts.Add(newFft);
+            FftsProcessed += newFfts.Length;
 
             newAudio.RemoveRange(0, newFftCount * settings.StepSize);
         }
 
-        public Bitmap GetBitmap(double multiplier = 1, bool dB = false)
+        public Bitmap GetBitmap(double multiplier = 1, bool dB = false, bool roll = false)
         {
             if (Width == 0)
                 return null;
@@ -103,9 +102,17 @@ public Bitmap GetBitmap(double multiplier = 1, bool dB = false)
             byte[] bytes = new byte[bitmapData.Stride * bmp.Height];
             for (int col = 0; col < Width; col++)
             {
+                int sourceCol = col;
+                if (roll)
+                {
+                    sourceCol += Width - FftsProcessed % Width;
+                    if (sourceCol >= Width)
+                        sourceCol -= Width;
+                }
+
                 for (int row = 0; row < Height; row++)
                 {
-                    double value = ffts[col][row];
+                    double value = ffts[sourceCol][row];
                     if (dB)
                         value = 20 * Math.Log10(value + 1);
                     value *= multiplier;
