more reorganization of WPF demo code, also attempting to improve the FFT display

NAudio/Dsp/FastFourierTransform.cs

@@ -2,17 +2,17 @@ using System;
 
 namespace NAudio.Dsp
 {
-	/// <summary>
-	/// Summary description for FastFourierTransform.
-	/// </summary>
-	public class FastFourierTransform
-	{
-		/// <summary>
-		/// This computes an in-place complex-to-complex FFT 
-		/// x and y are the real and imaginary arrays of 2^m points.
-		/// </summary>
+    /// <summary>
+    /// Summary description for FastFourierTransform.
+    /// </summary>
+    public class FastFourierTransform
+    {
+        /// <summary>
+        /// This computes an in-place complex-to-complex FFT 
+        /// x and y are the real and imaginary arrays of 2^m points.
+        /// </summary>
         public static void FFT(bool forward, int m, Complex[] data)
-		{
+        {
             int n, i, i1, j, k, i2, l, l1, l2;
             float c1, c2, tx, ty, t1, t2, u1, u2, z;
 
@@ -87,5 +87,5 @@ namespace NAudio.Dsp
                 }
             }
         }
-	}
+    }
 }

NAudioWpfDemo/AudioPlaybackDemo.cs → NAudioWpfDemo/AudioPlaybackDemo/AudioPlaybackDemoPlugin.cs

@@ -8,10 +8,10 @@ using System.ComponentModel.Composition;
 namespace NAudioWpfDemo
 {
     [Export(typeof(IModule))]
-    class AudioPlaybackDemo : IModule
+    class AudioPlaybackDemoPlugin : IModule
     {
         AudioPlaybackDemoView view;
-        ControlPanelViewModel viewModel;
+        AudioPlaybackViewModel viewModel;
 
         public string Name
         {
@@ -26,8 +26,8 @@ namespace NAudioWpfDemo
         private void CreateView()
         {
             view = new AudioPlaybackDemoView();
-            this.viewModel = new ControlPanelViewModel(view.waveForm, view.analyzer);
-            view.controlPanel.DataContext = viewModel;
+            this.viewModel = new AudioPlaybackViewModel(view.waveForm, view.analyzer);
+            view.DataContext = viewModel;
         }
 
         public void Deactivate()

NAudioWpfDemo/AudioPlaybackDemoView.xaml → NAudioWpfDemo/AudioPlaybackDemo/AudioPlaybackDemoView.xaml

@@ -14,6 +14,16 @@
         </Grid.RowDefinitions>
         <local:PolygonWaveFormControl x:Name="waveForm"/>
         <local:SpectrumAnalyser x:Name="analyzer" Grid.Row="1"/>
-        <local:ControlPanel x:Name="controlPanel" Grid.Row="2" />
+        <StackPanel Orientation="Horizontal" Grid.Row="2">
+            <Button Command="{Binding CaptureCommand}" Margin="2" ToolTip="Record">
+                <Ellipse Fill="Red" Width="15" Height="15" Margin="3"/>
+            </Button>
+            <Button Command="{Binding StopCommand}" Margin="2" ToolTip="Stop">
+                <Rectangle Fill="DarkBlue" Width="15" Height="15" Margin="3" RadiusX="2" RadiusY="2"/>
+            </Button>
+            <Button Command="{Binding PlayFileCommand}" Margin="2" ToolTip="Play">
+                <Path Fill="DarkGreen" Margin="3" Width="15" Height="15" Data="M 0,0 L 1,1 L 0,2 Z" Stretch="Fill" StrokeLineJoin="Round"/>
+            </Button>
+        </StackPanel>
     </Grid>
 </UserControl>

NAudioWpfDemo/AudioPlaybackDemoView.xaml.cs → NAudioWpfDemo/AudioPlaybackDemo/AudioPlaybackDemoView.xaml.cs

@@ -19,7 +19,7 @@ namespace NAudioWpfDemo
     /// </summary>
     public partial class AudioPlaybackDemoView : UserControl
     {
-        ControlPanelViewModel viewModel;
+        AudioPlaybackViewModel viewModel;
 
         public AudioPlaybackDemoView()
         {

NAudioWpfDemo/ControlPanelViewModel.cs → NAudioWpfDemo/AudioPlaybackDemo/AudioPlaybackViewModel.cs

@@ -10,14 +10,14 @@ using NAudio.Wave;
 
 namespace NAudioWpfDemo
 {
-    class ControlPanelViewModel : INotifyPropertyChanged, IDisposable
+    class AudioPlaybackViewModel : INotifyPropertyChanged, IDisposable
     {
         int captureSeconds;
         AudioGraph audioGraph;
         IWaveFormRenderer waveFormRenderer;
         SpectrumAnalyser analyzer;
 
-        public ControlPanelViewModel(IWaveFormRenderer waveFormRenderer, SpectrumAnalyser analyzer)
+        public AudioPlaybackViewModel(IWaveFormRenderer waveFormRenderer, SpectrumAnalyser analyzer)
         {
             this.waveFormRenderer = waveFormRenderer;
             this.analyzer = analyzer;

NAudioWpfDemo/SampleAggregator.cs → NAudioWpfDemo/AudioPlaybackDemo/SampleAggregator.cs

@@ -30,7 +30,7 @@ namespace NAudioWpfDemo
             {
                 throw new ArgumentException("FFT Length must be a power of two");
             }
-            this.m = (int)Math.Log(fftLength, 2.0); // (int)(Math.Log(fftLength) / Math.Log(2.0) + 0.5);
+            this.m = (int)Math.Log(fftLength, 2.0);
             this.fftLength = fftLength;
             this.fftBuffer = new Complex[fftLength];
             this.fftArgs = new FftEventArgs(fftBuffer);

NAudioWpfDemo/ControlPanel.xaml

@@ -1,18 +0,0 @@
-<UserControl x:Class="NAudioWpfDemo.ControlPanel"
-    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
-    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
-    Height="Auto" Width="Auto">
-    <Grid Margin="5">
-        <StackPanel Orientation="Horizontal" >
-        <Button Command="{Binding CaptureCommand}" Margin="2" ToolTip="Record">
-            <Ellipse Fill="Red" Width="15" Height="15" Margin="3"/>
-        </Button>
-        <Button Command="{Binding StopCommand}" Margin="2" ToolTip="Stop">
-            <Rectangle Fill="DarkBlue" Width="15" Height="15" Margin="3" RadiusX="2" RadiusY="2"/>
-        </Button>
-            <Button Command="{Binding PlayFileCommand}" Margin="2" ToolTip="Play">
-                <Path Fill="DarkGreen" Margin="3" Width="15" Height="15" Data="M 0,0 L 1,1 L 0,2 Z" Stretch="Fill" StrokeLineJoin="Round"/>
-            </Button>
-        </StackPanel>
-    </Grid>
-</UserControl>

NAudioWpfDemo/ControlPanel.xaml.cs

@@ -1,27 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-using System.Windows;
-using System.Windows.Controls;
-using System.Windows.Data;
-using System.Windows.Documents;
-using System.Windows.Input;
-using System.Windows.Media;
-using System.Windows.Media.Imaging;
-using System.Windows.Navigation;
-using System.Windows.Shapes;
-
-namespace NAudioWpfDemo
-{
-    /// <summary>
-    /// Interaction logic for ControlPanel.xaml
-    /// </summary>
-    public partial class ControlPanel : UserControl
-    {
-        public ControlPanel()
-        {
-            InitializeComponent();
-        }
-    }
-}

NAudioWpfDemo/NAudioWpfDemo.csproj

@@ -91,16 +91,10 @@
       <Generator>MSBuild:Compile</Generator>
       <SubType>Designer</SubType>
     </ApplicationDefinition>
-    <Page Include="AudioPlaybackDemoView.xaml">
+    <Page Include="AudioPlaybackDemo\AudioPlaybackDemoView.xaml">
       <SubType>Designer</SubType>
       <Generator>MSBuild:Compile</Generator>
     </Page>
-    <Page Include="ControlPanel.xaml">
-      <SubType>Designer</SubType>
-      <Generator>MSBuild:Compile</Generator>
-      <Generator>MSBuild:Compile</Generator>
-      <SubType>Designer</SubType>
-    </Page>
     <Page Include="PolygonWaveFormControl.xaml">
       <Generator>MSBuild:Compile</Generator>
       <SubType>Designer</SubType>
@@ -135,8 +129,8 @@
       <DependentUpon>App.xaml</DependentUpon>
       <SubType>Code</SubType>
     </Compile>
-    <Compile Include="AudioPlaybackDemo.cs" />
-    <Compile Include="AudioPlaybackDemoView.xaml.cs">
+    <Compile Include="AudioPlaybackDemo\AudioPlaybackDemoPlugin.cs" />
+    <Compile Include="AudioPlaybackDemo\AudioPlaybackDemoView.xaml.cs">
       <DependentUpon>AudioPlaybackDemoView.xaml</DependentUpon>
     </Compile>
     <Compile Include="IModule.cs" />
@@ -146,13 +140,10 @@
     </Compile>
   </ItemGroup>
   <ItemGroup>
-    <Compile Include="AudioCapture.cs" />
-    <Compile Include="AudioGraph.cs" />
-    <Compile Include="AudioPlayback.cs" />
-    <Compile Include="ControlPanel.xaml.cs">
-      <DependentUpon>ControlPanel.xaml</DependentUpon>
-    </Compile>
-    <Compile Include="ControlPanelViewModel.cs" />
+    <Compile Include="AudioPlaybackDemo\AudioCapture.cs" />
+    <Compile Include="AudioPlaybackDemo\AudioGraph.cs" />
+    <Compile Include="AudioPlaybackDemo\AudioPlayback.cs" />
+    <Compile Include="AudioPlaybackDemo\AudioPlaybackViewModel.cs" />
     <Compile Include="MainWindowViewModel.cs" />
     <Compile Include="PolygonWaveFormControl.xaml.cs">
       <DependentUpon>PolygonWaveFormControl.xaml</DependentUpon>
@@ -175,14 +166,14 @@
       <DesignTimeSharedInput>True</DesignTimeSharedInput>
     </Compile>
     <Compile Include="RelayCommand.cs" />
-    <Compile Include="SampleAggregator.cs" />
+    <Compile Include="AudioPlaybackDemo\SampleAggregator.cs" />
     <Compile Include="SpectrumAnalyser.xaml.cs">
       <DependentUpon>SpectrumAnalyser.xaml</DependentUpon>
     </Compile>
     <Compile Include="WaveFormControl.xaml.cs">
       <DependentUpon>WaveFormControl.xaml</DependentUpon>
     </Compile>
-    <Compile Include="WaveformVisual.cs" />
+    <Compile Include="AudioPlaybackDemo\WaveformVisual.cs" />
     <EmbeddedResource Include="Properties\Resources.resx">
       <Generator>ResXFileCodeGenerator</Generator>
       <LastGenOutput>Resources.Designer.cs</LastGenOutput>
@@ -217,6 +208,7 @@
       <Install>true</Install>
     </BootstrapperPackage>
   </ItemGroup>
+  <ItemGroup />
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
   <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
        Other similar extension points exist, see Microsoft.Common.targets.

NAudioWpfDemo/SpectrumAnalyser.xaml.cs

@@ -38,40 +38,66 @@ namespace NAudioWpfDemo
 
         void SpectrumAnalyser_SizeChanged(object sender, SizeChangedEventArgs e)
         {
-            CalculateXScale();            
+            CalculateXScale();
         }
 
         private void CalculateXScale()
         {
-            this.xScale = this.ActualWidth / bins;
+            this.xScale = this.ActualWidth / (bins / binsPerPoint);
         }
 
+        private const int binsPerPoint = 2; // reduce the number of points we plot for a less jagged line?
+        private int updateCount;
+
         public void Update(Complex[] fftResults)
         {
+            // no need to repaint too many frames per second
+            if (updateCount++ % 2 == 0)
+            {
+                return;
+            }
+
             if (fftResults.Length / 2 != bins)
             {
                 this.bins = fftResults.Length / 2;
                 CalculateXScale();
             }
             
-            this.xScale = this.ActualWidth / bins;
-            for (int n = 0; n < fftResults.Length / 2; n++)
+            for (int n = 0; n < fftResults.Length / 2; n+= binsPerPoint)
             {
-                //double yScale = 1000
-                //double intensity = Math.Sqrt(fftResults[n].X * fftResults[n].X + fftResults[n].Y * fftResults[n].Y);
-                //double yPos = this.ActualHeight - intensity * yScale;
+                double yPos = GetYPosLog(fftResults[n]);
+                AddResult(n / binsPerPoint, yPos);
+            }
+        }
 
-                // can also try 5 * without the sqrt seems to give decent results
-                double intensityDB = 10 * Math.Log(Math.Sqrt(fftResults[n].X * fftResults[n].X + fftResults[n].Y * fftResults[n].Y));
-                double minDB = -96;
-                if (intensityDB < minDB) intensityDB = minDB;
-                double percent = intensityDB / minDB;
-                // we want 0dB to be at the top (i.e. yPos = 0)
-                double yPos = percent * this.ActualHeight;
+        private double GetYPosIntensityOnly(Complex c)
+        {
+            double yScale = 1000;
+            double intensity = Math.Sqrt(c.X * c.X + c.Y * c.Y);
+            double yPos = this.ActualHeight - intensity * yScale;
+            return yPos;
+        }
 
-                
-                AddResult(n, yPos);
-            }
+        private double GetYPosLog(Complex c)
+        {
+            // in theory should be 20x to get the power, but doesn't seem to give me sensible values (may be because we throw half the FFT away - bin 0 might need to be halved)
+            double intensityDB = 10 * Math.Log(Math.Sqrt(c.X * c.X + c.Y * c.Y));
+            double minDB = -96;
+            if (intensityDB < minDB) intensityDB = minDB;
+            double percent = intensityDB / minDB;
+            // we want 0dB to be at the top (i.e. yPos = 0)
+            double yPos = percent * this.ActualHeight;
+            return yPos;
+        }
+
+        private double GetYPosAnotherTry(Complex c, int binNumber, int fftLength)
+        {
+            // this technique based on http://www.mathworks.com/support/tech-notes/1700/1702.html
+            double abs = Math.Sqrt(c.X * c.X + c.Y * c.Y); // do not scale by FFT length as NAudio already does this.
+            abs = abs * abs;
+            if (binNumber != 0) abs *= 2;
+            double yPos = abs * this.ActualHeight;
+            return yPos;
         }
 
         private void AddResult(int index, double power)