Added first working visualization

KeyboardAudioVisualizer/App.xaml.cs

@@ -2,6 +2,7 @@
 using System.IO;
 using System.Windows;
 using Hardcodet.Wpf.TaskbarNotification;
+using KeyboardAudioVisualizer.AudioProcessing;
 using KeyboardAudioVisualizer.Helper;
 
 namespace KeyboardAudioVisualizer
@@ -42,6 +43,9 @@ namespace KeyboardAudioVisualizer
                     _taskbarIcon.ShowBalloonTip("Keyboard Audio-Visualizer is starting in the tray!", "Click on the icon to open the configuration.", BalloonIcon.Info);
                 }
                 ApplicationManager.Instance.Settings = settings;
+
+                AudioProcessor.Initialize();
+                ApplicationManager.Instance.InitializeDevices();
             }
             catch (Exception ex)
             {

KeyboardAudioVisualizer/ApplicationManager.cs

@@ -1,6 +1,13 @@
 using System.Windows;
+using KeyboardAudioVisualizer.AudioProcessing;
+using KeyboardAudioVisualizer.Brushes;
 using KeyboardAudioVisualizer.Helper;
 using KeyboardAudioVisualizer.UI;
+using RGB.NET.Brushes;
+using RGB.NET.Brushes.Gradients;
+using RGB.NET.Core;
+using RGB.NET.Devices.Corsair;
+using RGB.NET.Groups;
 
 namespace KeyboardAudioVisualizer
 {
@@ -28,13 +35,37 @@ namespace KeyboardAudioVisualizer
 
         #region Constructors
 
-        private ApplicationManager()
-        { }
+        private ApplicationManager() { }
 
         #endregion
 
         #region Methods
 
+        public void InitializeDevices()
+        {
+            RGBSurface surface = RGBSurface.Instance;
+            //surface.Exception += args =>;
+
+            surface.UpdateFrequency = 1 / 30.0; //TODO DarthAffe 03.08.2017: Settings
+            surface.UpdateMode = UpdateMode.Continuous;
+
+            surface.LoadDevices(CorsairDeviceProvider.Instance);
+            //surface.LoadDevices(LogitechDeviceProvider.Instance);
+            //surface.LoadDevices(CoolerMasterDeviceProvider.Instance);
+
+            ILedGroup background = new ListLedGroup(surface.Leds);
+            background.Brush = new SolidColorBrush(new Color(0, 0, 0));
+
+            //TODO DarthAffe 03.08.2017: Changeable, Settings etc.
+            foreach (IRGBDevice device in surface.Devices)
+            {
+                if (device.DeviceInfo.DeviceType == RGBDeviceType.Keyboard)
+                    new ListLedGroup(device).Brush = new FrequencyBarsBrush(AudioProcessor.Instance.PrimaryVisualizationProvider, new RainbowGradient(300, -14));
+            }
+
+            surface.Updating += args => AudioProcessor.Instance.Update();
+        }
+
         private void OpenConfiguration()
         {
             if (_configurationWindow == null) _configurationWindow = new ConfigurationWindow();

KeyboardAudioVisualizer/AudioCapture/AudioBuffer.cs

@@ -0,0 +1,79 @@
+namespace KeyboardAudioVisualizer.AudioCapture
+{
+    public class AudioBuffer
+    {
+        #region Properties & Fields
+
+        private readonly int _capacity;
+        private readonly float[] _bufferLeft;
+        private readonly float[] _bufferRight;
+        private int _currentIndex;
+
+        public int Size => _capacity;
+
+        #endregion
+
+        #region Constructors
+
+        public AudioBuffer(int capacity)
+        {
+            this._capacity = capacity;
+
+            _bufferLeft = new float[capacity];
+            _bufferRight = new float[capacity];
+        }
+
+        #endregion
+
+        #region Methods
+
+        public void Put(float[] src, int offset, int count)
+        {
+            lock (_bufferLeft)
+            {
+                if ((count & 1) != 0) return; // we expect stereo-data to be an even amount of values
+
+                if (count > _capacity)
+                {
+                    offset += count - _capacity;
+                    count = _capacity;
+                }
+
+                for (int i = 0; i < count; i += 2)
+                {
+                    _currentIndex++;
+                    if (_currentIndex >= _capacity) _currentIndex = 0;
+
+                    _bufferLeft[_currentIndex] = src[offset + i];
+                    _bufferRight[_currentIndex] = src[offset + i + 1];
+                }
+            }
+        }
+
+        public void CopyLeftInto(ref float[] data, int offset)
+        {
+            lock (_bufferLeft)
+                for (int i = 0; i < _capacity; i++)
+                    data[offset + i] = _bufferLeft[(_currentIndex + i) % _capacity];
+        }
+
+        public void CopyRightInto(ref float[] data, int offset)
+        {
+            lock (_bufferLeft)
+                for (int i = 0; i < _capacity; i++)
+                    data[offset + i] = _bufferRight[(_currentIndex + i) % _capacity];
+        }
+
+        public void CopyMixInto(ref float[] data, int offset)
+        {
+            lock (_bufferLeft)
+                for (int i = 0; i < _capacity; i++)
+                {
+                    int index = (_currentIndex + i) % _capacity;
+                    data[offset + i] = (_bufferLeft[index] + _bufferRight[index]) / 2f;
+                }
+        }
+
+        #endregion
+    }
+}

KeyboardAudioVisualizer/AudioCapture/CSCoreAudioInput.cs

@@ -0,0 +1,50 @@
+using CSCore;
+using CSCore.SoundIn;
+using CSCore.Streams;
+
+namespace KeyboardAudioVisualizer.AudioCapture
+{
+    public class CSCoreAudioInput : IAudioInput
+    {
+        #region Properties & Fields
+
+        private WasapiCapture _capture;
+        private SoundInSource _soundInSource;
+        private SingleBlockNotificationStream _stream;
+
+        private readonly float[] _readBuffer = new float[2048];
+
+        public int SampleRate => _soundInSource?.WaveFormat?.SampleRate ?? -1;
+
+        #endregion
+
+        #region Event
+
+        public event AudioData DataAvailable;
+
+        #endregion
+
+        #region Methods
+
+        public void Initialize()
+        {
+            _capture = new WasapiLoopbackCapture();
+            _capture.Initialize();
+            _soundInSource = new SoundInSource(_capture) { FillWithZeros = false };
+            _stream = new SingleBlockNotificationStream(_soundInSource.ToStereo().ToSampleSource());
+
+            _soundInSource.DataAvailable += OnSoundDataAvailable;
+
+            _capture.Start();
+        }
+
+        private void OnSoundDataAvailable(object sender, DataAvailableEventArgs dataAvailableEventArgs)
+        {
+            int readCount;
+            while ((readCount = _stream.Read(_readBuffer, 0, _readBuffer.Length)) > 0)
+                DataAvailable?.Invoke(_readBuffer, 0, readCount);
+        }
+
+        #endregion
+    }
+}

KeyboardAudioVisualizer/AudioCapture/IAudioInput.cs

@@ -0,0 +1,13 @@
+namespace KeyboardAudioVisualizer.AudioCapture
+{
+    public delegate void AudioData(float[] data, int offset, int count);
+
+    public interface IAudioInput
+    {
+        int SampleRate { get; }
+
+        event AudioData DataAvailable;
+
+        void Initialize();
+    }
+}

KeyboardAudioVisualizer/AudioProcessing/AudioProcessor.cs

@@ -0,0 +1,77 @@
+using KeyboardAudioVisualizer.AudioCapture;
+using KeyboardAudioVisualizer.AudioProcessing.Equalizer;
+using KeyboardAudioVisualizer.AudioProcessing.Spectrum;
+using KeyboardAudioVisualizer.AudioProcessing.VisualizationPRovider;
+
+namespace KeyboardAudioVisualizer.AudioProcessing
+{
+    public class AudioProcessor
+    {
+        #region Constants
+
+        private const int MAXIMUM_UPDATE_RATE = 40; // We won't allow to change the FPS beyond this
+
+        #endregion
+
+        #region Properties & Fields
+
+        public static AudioProcessor Instance { get; private set; }
+
+        private AudioBuffer _audioBuffer;
+        private IAudioInput _audioInput;
+        private ISpectrumProvider _spectrumProvider;
+        public IVisualizationProvider PrimaryVisualizationProvider { get; private set; }
+
+        #endregion
+
+        #region Constructors
+
+        private AudioProcessor() { }
+
+        #endregion
+
+        #region Methods
+
+        public void Update()
+        {
+            _spectrumProvider.Update();
+            PrimaryVisualizationProvider.Update();
+        }
+
+        public static void Initialize()
+        {
+            if (Instance != null) return;
+
+            Instance = new AudioProcessor();
+            Instance.InitializeInstance();
+        }
+
+        private void InitializeInstance()
+        {
+            _audioInput = new CSCoreAudioInput();
+            _audioInput.Initialize();
+
+            _audioBuffer = new AudioBuffer(CalculateSampleSize(_audioInput.SampleRate, MAXIMUM_UPDATE_RATE));
+            _audioInput.DataAvailable += (data, offset, count) => _audioBuffer.Put(data, offset, count);
+
+            _spectrumProvider = new FourierSpectrumProvider(_audioBuffer, _audioInput.SampleRate);
+            _spectrumProvider.Initialize();
+
+            //TODO DarthAffe 03.08.2017: Initialize correctly; Settings
+            MultiBandEqualizer equalizer = new MultiBandEqualizer { [0] = -5, [1] = -1, [2] = 0, [3] = 2, [4] = 2 };
+            PrimaryVisualizationProvider = new FrequencyBarsVisualizationProvider(new FrequencyBarsVisualizationProviderConfiguration { Scale = 38 }, _spectrumProvider) { Equalizer = equalizer };
+            PrimaryVisualizationProvider.Initialize();
+        }
+
+        private int CalculateSampleSize(int sampleRate, int maximumUpdateRate)
+        {
+            int sampleSize = 2;
+            while ((sampleSize * maximumUpdateRate) < sampleRate)
+                sampleSize <<= 1;
+
+            return sampleSize;
+        }
+
+        #endregion
+    }
+}

KeyboardAudioVisualizer/AudioProcessing/Equalizer/IEqualizer.cs

@@ -0,0 +1,8 @@
+namespace KeyboardAudioVisualizer.AudioProcessing.Equalizer
+{
+    public interface IEqualizer
+    {
+        bool IsEnabled { get; set; }
+        float[] CalculateValues(int values);
+    }
+}

KeyboardAudioVisualizer/AudioProcessing/Equalizer/MultiBandEqualizer.cs

@@ -0,0 +1,105 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace KeyboardAudioVisualizer.AudioProcessing.Equalizer
+{
+    public class MultiBandEqualizer : IEqualizer
+    {
+        #region Properties & Fields
+
+        private float[] _values;
+
+        private readonly List<Band> _bands = new List<Band>();
+
+        public int Bands => _bands.Count;
+        public float this[int band]
+        {
+            get => _bands[band].Value;
+            set
+            {
+                _bands[band].Value = value;
+                RecalculateValues();
+            }
+        }
+
+        public bool IsEnabled { get; set; } = true;
+
+        #endregion
+
+        #region Constructors
+
+        public MultiBandEqualizer(int bands = 5)
+        {
+            if (bands < 2) throw new ArgumentOutOfRangeException(nameof(bands), "There must be at least two bands for an working equalizer!");
+
+            float reference = (float)Math.Log(bands);
+
+            for (int i = bands - 1; i >= 0; i--)
+            {
+                Band band = new Band((reference - (float)Math.Log(i + 1)) / reference);
+                _bands.Add(band);
+            }
+
+            CalculateValues(1);
+        }
+
+        #endregion
+
+        #region Methods
+
+        public float[] CalculateValues(int values)
+        {
+            if ((_values == null) || (_values.Length != values))
+            {
+                _values = new float[values];
+                RecalculateValues();
+            }
+
+            return _values;
+        }
+
+        private void RecalculateValues()
+        {
+            float width = _values.Length;
+            for (int i = 0; i < _values.Length; i++)
+            {
+                float offset = (i / width);
+
+                Band bandBefore = _bands.Last(n => n.Offset <= offset);
+                Band bandAfter = _bands.First(n => n.Offset >= offset);
+
+                offset = bandAfter.Offset <= 0 ? 0 : (offset - bandBefore.Offset) / (bandAfter.Offset - bandBefore.Offset);
+
+                float value = (float)((3.0 * (offset * offset)) - (2.0 * (offset * offset * offset)));
+                _values[i] = bandBefore.Value + (value * (bandAfter.Value - bandBefore.Value));
+            }
+        }
+
+        #endregion
+
+        #region Data
+
+        private class Band
+        {
+            #region Properties & Fields
+
+            public float Offset { get; set; }
+            public float Value { get; set; }
+
+            #endregion
+
+            #region Constructors
+
+            public Band(float offset, float value = 0)
+            {
+                this.Offset = offset;
+                this.Value = value;
+            }
+
+            #endregion
+        }
+
+        #endregion
+    }
+}

KeyboardAudioVisualizer/AudioProcessing/IAudioProcessor.cs

@@ -0,0 +1,8 @@
+namespace KeyboardAudioVisualizer.AudioProcessing
+{
+    public interface IAudioProcessor
+    {
+        void Initialize();
+        void Update();
+    }
+}

KeyboardAudioVisualizer/AudioProcessing/Spectrum/FourierSpectrumProvider.cs

@@ -0,0 +1,79 @@
+using KeyboardAudioVisualizer.AudioCapture;
+using MathNet.Numerics;
+using MathNet.Numerics.IntegralTransforms;
+
+namespace KeyboardAudioVisualizer.AudioProcessing.Spectrum
+{
+    public class FourierSpectrumProvider : ISpectrumProvider
+    {
+        #region Properties & Fields
+
+        private readonly AudioBuffer _audioBuffer;
+
+        private float[] _sampleData;
+        private double[] _hamming;
+
+        private float[] _spectrum;
+        public float[] Spectrum => _spectrum;
+
+        public int SampleRate { get; private set; }
+        public float Resolution { get; private set; }
+
+        #endregion
+
+        #region Constructors
+
+        public FourierSpectrumProvider(AudioBuffer audioBuffer, int sampleRate)
+        {
+            this._audioBuffer = audioBuffer;
+            this.SampleRate = sampleRate;
+        }
+
+        #endregion
+
+        #region Methods
+
+        public void Initialize()
+        {
+            _hamming = Window.Hamming(_audioBuffer.Size);
+            _sampleData = new float[_audioBuffer.Size];
+            _spectrum = new float[_audioBuffer.Size / 2];
+            Resolution = (float)SampleRate / (float)_audioBuffer.Size;
+        }
+
+        public void Update()
+        {
+            _audioBuffer.CopyMixInto(ref _sampleData, 0);
+            ApplyHamming(ref _sampleData);
+            CreateSpectrum(ref _sampleData);
+        }
+
+        private void ApplyHamming(ref float[] data)
+        {
+            for (int i = 0; i < data.Length; i++)
+                data[i] = (float)(data[i] * _hamming[i]);
+        }
+
+        private void CreateSpectrum(ref float[] data)
+        {
+            Complex32[] complexData = CreateComplexData(ref data);
+            Fourier.Forward(complexData, FourierOptions.NoScaling);
+            for (int i = 0; i < _spectrum.Length; i++)
+            {
+                Complex32 fourierData = complexData[i];
+                _spectrum[i] = (fourierData.Real * fourierData.Real) + (fourierData.Imaginary * fourierData.Imaginary);
+            }
+        }
+
+        private static Complex32[] CreateComplexData(ref float[] data)
+        {
+            Complex32[] complexData = new Complex32[data.Length];
+            for (int i = 0; i < data.Length; i++)
+                complexData[i] = new Complex32(data[i], 0);
+
+            return complexData;
+        }
+
+        #endregion   
+    }
+}

KeyboardAudioVisualizer/AudioProcessing/Spectrum/ISpectrumProvider.cs

@@ -0,0 +1,9 @@
+namespace KeyboardAudioVisualizer.AudioProcessing.Spectrum
+{
+    public interface ISpectrumProvider : IAudioProcessor
+    {
+        float[] Spectrum { get; }
+        int SampleRate { get; }
+        float Resolution { get; }
+    }
+}

KeyboardAudioVisualizer/AudioProcessing/VisualizationPRovider/FrequencyBarsVisualizationProvider.cs

@@ -0,0 +1,183 @@
+using System;
+using System.Linq;
+using KeyboardAudioVisualizer.AudioProcessing.Equalizer;
+using KeyboardAudioVisualizer.AudioProcessing.Spectrum;
+using KeyboardAudioVisualizer.Configuration;
+using KeyboardAudioVisualizer.Helper;
+
+namespace KeyboardAudioVisualizer.AudioProcessing.VisualizationPRovider
+{
+    #region Configuration
+
+    public class FrequencyBarsVisualizationProviderConfiguration : AbstractConfiguration
+    {
+        private int _bars = 48;
+        public int Bars
+        {
+            get => _bars;
+            set => SetProperty(ref _bars, value);
+        }
+
+        private double _smoothing = 8;
+        public double Smoothing
+        {
+            get => _smoothing;
+            set => SetProperty(ref _smoothing, value);
+        }
+
+        private double _minFrequency = 100;
+        public double MinFrequency
+        {
+            get => _minFrequency;
+            set => SetProperty(ref _minFrequency, value);
+        }
+
+        private double _maxFrequency = 15000;
+        public double MaxFrequency
+        {
+            get => _maxFrequency;
+            set => SetProperty(ref _maxFrequency, value);
+        }
+
+        private double _scale = 20;
+        public double Scale
+        {
+            get => _scale;
+            set => SetProperty(ref _scale, value);
+        }
+
+        private int _emphasisePeaks = 1;
+        public int EmphasisePeaks
+        {
+            get => _emphasisePeaks;
+            set => SetProperty(ref _emphasisePeaks, value);
+        }
+
+        private double _gamma = 3;
+        public double Gamma
+        {
+            get => _gamma;
+            set => SetProperty(ref _gamma, value);
+        }
+    }
+
+    #endregion
+
+    public class FrequencyBarsVisualizationProvider : IVisualizationProvider
+    {
+        #region Properties & Fields
+
+        private readonly FrequencyBarsVisualizationProviderConfiguration _configuration;
+        private readonly ISpectrumProvider _spectrumProvider;
+
+        private int _frequencySkipCount;
+        private int _frequencyCount;
+        private double _smoothingFactor;
+        private double _scalingValue;
+
+        public IEqualizer Equalizer { get; set; }
+        public float[] VisualizationData { get; private set; }
+
+        #endregion
+
+        #region Constructors
+
+        public FrequencyBarsVisualizationProvider(FrequencyBarsVisualizationProviderConfiguration configuration, ISpectrumProvider spectrumProvider)
+        {
+            this._configuration = configuration;
+            this._spectrumProvider = spectrumProvider;
+
+            configuration.PropertyChanged += (sender, args) => RecalculateConfigValues(args.PropertyName);
+        }
+
+        #endregion
+
+        #region Methods
+
+        public void Initialize() => RecalculateConfigValues(null);
+
+        private void RecalculateConfigValues(string changedPropertyName)
+        {
+            if ((changedPropertyName == null) || (changedPropertyName == nameof(FrequencyBarsVisualizationProviderConfiguration.Bars)))
+                VisualizationData = new float[_configuration.Bars];
+
+            if ((changedPropertyName == null) || (changedPropertyName == nameof(FrequencyBarsVisualizationProviderConfiguration.Smoothing)))
+                _smoothingFactor = Math.Pow((0.0000025 * Math.Pow(2, _configuration.Smoothing)), ((double)_spectrumProvider.Spectrum.Length * 2) / (double)_spectrumProvider.SampleRate);
+
+            if ((changedPropertyName == null)
+                || (changedPropertyName == nameof(FrequencyBarsVisualizationProviderConfiguration.MinFrequency))
+                || (changedPropertyName == nameof(FrequencyBarsVisualizationProviderConfiguration.MaxFrequency)))
+                CalculateFrequencyCount(MathHelper.Clamp(_configuration.MinFrequency, 0, _spectrumProvider.SampleRate / 2.0),
+                                        MathHelper.Clamp(_configuration.MaxFrequency, 0, _spectrumProvider.SampleRate / 2.0),
+                                        _spectrumProvider.SampleRate, _spectrumProvider.Spectrum.Length * 2);
+
+            if ((changedPropertyName == null) || (changedPropertyName == nameof(FrequencyBarsVisualizationProviderConfiguration.Scale)))
+                _scalingValue = _configuration.Scale * 0.0001;
+        }
+
+        private void CalculateFrequencyCount(double minFrequency, double maxFrequency, int sampleRate, int sampleSize)
+        {
+            int firstFrequency = Math.Max(0, (int)Math.Ceiling((minFrequency / sampleRate) * sampleSize) - 1);
+            int lastFrequency = Math.Max(firstFrequency, (int)Math.Ceiling((maxFrequency / sampleRate) * sampleSize));
+
+            if (firstFrequency == lastFrequency)
+            {
+                if (firstFrequency == 0) lastFrequency++;
+                else firstFrequency--;
+            }
+
+            _frequencyCount = lastFrequency - firstFrequency;
+            _frequencySkipCount = firstFrequency;
+        }
+
+        public void Update()
+        {
+            float[] spectrum = _spectrumProvider.Spectrum.Skip(_frequencySkipCount).Take(_frequencyCount).ToArray();
+
+            int startFrequency = 0;
+            for (int i = 0; i < VisualizationData.Length; i++)
+            {
+                int endFrequency = Math.Max(startFrequency + 1, Math.Min(_frequencyCount, (int)Math.Round(Math.Pow((i + 1f) / VisualizationData.Length, _configuration.Gamma) * _frequencyCount)));
+                int bandWidth = endFrequency - startFrequency;
+                double binPower = 0;
+
+                for (int j = 0; j < bandWidth; j++)
+                {
+                    float power = spectrum[Math.Min(spectrum.Length - 1, startFrequency + j)];
+                    binPower = Math.Max(power, binPower);
+                }
+
+                if (Equalizer?.IsEnabled == true)
+                {
+                    float value = Equalizer.CalculateValues(VisualizationData.Length)[i];
+                    if (Math.Abs(value) > 0.000001)
+                    {
+                        bool lower = value < 0;
+                        value = 1 + (value * value);
+                        binPower *= lower ? 1f / value : value;
+                    }
+                }
+
+                binPower = Math.Log(binPower);
+                binPower = Math.Max(0, binPower);
+
+                if (_configuration.EmphasisePeaks == 1)
+                {
+                    binPower *= binPower;
+                    binPower *= 0.15;
+                }
+                if (_configuration.EmphasisePeaks == 2)
+                    binPower *= binPower * binPower;
+                else
+                    binPower *= 40;
+
+                VisualizationData[i] = (float)((VisualizationData[i] * _smoothingFactor) + (binPower * _scalingValue * (1.0 - _smoothingFactor)));
+                if (double.IsNaN(VisualizationData[i])) VisualizationData[i] = 0;
+
+                startFrequency = endFrequency;
+            }
+        }
+
+        #endregion
+    }
+}

KeyboardAudioVisualizer/AudioProcessing/VisualizationPRovider/IVisualizationProvider.cs

@@ -0,0 +1,7 @@
+namespace KeyboardAudioVisualizer.AudioProcessing.VisualizationPRovider
+{
+    public interface IVisualizationProvider : IAudioProcessor
+    {
+        float[] VisualizationData { get; }
+    }
+}

KeyboardAudioVisualizer/Brushes/FrequencyBarsBrush.cs

@@ -0,0 +1,42 @@
+using System;
+using KeyboardAudioVisualizer.AudioProcessing.VisualizationPRovider;
+using RGB.NET.Brushes;
+using RGB.NET.Brushes.Gradients;
+using RGB.NET.Core;
+using Color = RGB.NET.Core.Color;
+using Rectangle = RGB.NET.Core.Rectangle;
+
+namespace KeyboardAudioVisualizer.Brushes
+{
+    public class FrequencyBarsBrush : LinearGradientBrush
+    {
+        #region Properties & Fields
+
+        private readonly IVisualizationProvider _visualizationProvider;
+
+        #endregion
+
+        #region Constructors
+
+        public FrequencyBarsBrush(IVisualizationProvider visualizationProvider, IGradient gradient)
+            : base(gradient)
+        {
+            this._visualizationProvider = visualizationProvider;
+        }
+
+        #endregion
+
+        #region Methods
+
+        protected override Color GetColorAtPoint(Rectangle rectangle, BrushRenderTarget renderTarget)
+        {
+            int barSampleIndex = (int)Math.Floor(_visualizationProvider.VisualizationData.Length * (renderTarget.Point.X / (rectangle.Location.X + rectangle.Size.Width)));
+            double curBarHeight = 1.0 - Math.Max(0f, _visualizationProvider.VisualizationData[barSampleIndex]);
+            double verticalPos = (renderTarget.Point.Y / rectangle.Size.Height);
+
+            return curBarHeight <= verticalPos ? base.GetColorAtPoint(rectangle, renderTarget) : Color.Transparent;
+        }
+
+        #endregion
+    }
+}

KeyboardAudioVisualizer/Configuration/AbstractConfiguration.cs

@@ -0,0 +1,38 @@
+using System;
+using System.ComponentModel;
+using System.Runtime.CompilerServices;
+
+namespace KeyboardAudioVisualizer.Configuration
+{
+    public class AbstractConfiguration : INotifyPropertyChanged
+    {
+        #region Events
+
+        public event PropertyChangedEventHandler PropertyChanged;
+
+        #endregion
+
+        #region Methods
+
+        protected virtual bool SetProperty<T>(ref T storage, T value, [CallerMemberName] string propertyName = null)
+        {
+            if ((typeof(T) == typeof(double)) || (typeof(T) == typeof(float)))
+            {
+                if (Math.Abs((double)(object)storage - (double)(object)value) < 0.000001) return false;
+            }
+            else
+            {
+                if (Equals(storage, value)) return false;
+            }
+
+            storage = value;
+            // ReSharper disable once ExplicitCallerInfoArgument
+            OnPropertyChanged(propertyName);
+            return true;
+        }
+
+        protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null) => PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
+
+        #endregion
+    }
+}

KeyboardAudioVisualizer/Helper/MathHelper.cs

@@ -0,0 +1,14 @@
+using System;
+
+namespace KeyboardAudioVisualizer.Helper
+{
+    public static class MathHelper
+    {
+        #region Methods
+
+        public static double Clamp(double value, double min, double max) => Math.Max(min, Math.Min(max / 2.0, value));
+        public static float Clamp(float value, float min, float max) => (float)Clamp((double)value, min, max);
+
+        #endregion
+    }
+}

KeyboardAudioVisualizer/KeyboardAudioVisualizer.csproj

@@ -63,6 +63,7 @@
     <Reference Include="System" />
     <Reference Include="System.Data" />
     <Reference Include="System.Drawing" />
+    <Reference Include="System.Numerics" />
     <Reference Include="System.Xml" />
     <Reference Include="Microsoft.CSharp" />
     <Reference Include="System.Core" />
@@ -86,9 +87,23 @@
       <SubType>Code</SubType>
     </Compile>
     <Compile Include="ApplicationManager.cs" />
+    <Compile Include="AudioCapture\AudioBuffer.cs" />
+    <Compile Include="AudioCapture\CSCoreAudioInput.cs" />
+    <Compile Include="AudioCapture\IAudioInput.cs" />
+    <Compile Include="AudioProcessing\AudioProcessor.cs" />
+    <Compile Include="AudioProcessing\Equalizer\IEqualizer.cs" />
+    <Compile Include="AudioProcessing\Equalizer\MultiBandEqualizer.cs" />
+    <Compile Include="AudioProcessing\IAudioProcessor.cs" />
+    <Compile Include="AudioProcessing\Spectrum\ISpectrumProvider.cs" />
+    <Compile Include="AudioProcessing\Spectrum\FourierSpectrumProvider.cs" />
+    <Compile Include="AudioProcessing\VisualizationPRovider\FrequencyBarsVisualizationProvider.cs" />
+    <Compile Include="AudioProcessing\VisualizationPRovider\IVisualizationProvider.cs" />
+    <Compile Include="Brushes\FrequencyBarsBrush.cs" />
+    <Compile Include="Configuration\AbstractConfiguration.cs" />
     <Compile Include="Controls\ImageButton.cs" />
     <Compile Include="Helper\ActionCommand.cs" />
     <Compile Include="Helper\ExceptionExtension.cs" />
+    <Compile Include="Helper\MathHelper.cs" />
     <Compile Include="Settings.cs" />
     <Compile Include="Controls\BlurredDecorationWindow.cs" />
     <Compile Include="Styles\CachedResourceDictionary.cs" />