Added FlashEffect

CUE.NET.csproj

@@ -55,6 +55,8 @@
     <Compile Include="Devices\Keyboard\Brushes\RadialGradientBrush.cs" />
     <Compile Include="Devices\Keyboard\Brushes\RandomColorBrush.cs" />
     <Compile Include="Devices\Keyboard\Brushes\SolidColorBrush.cs" />
+    <Compile Include="Devices\Keyboard\Effects\AbstractEffect.cs" />
+    <Compile Include="Devices\Keyboard\Effects\FlashEffect.cs" />
     <Compile Include="Devices\Keyboard\Effects\IEffect.cs" />
     <Compile Include="Devices\Keyboard\Effects\EffectTimeContainer.cs" />
     <Compile Include="Devices\Keyboard\Enums\CorsairLogicalKeyboardLayout.cs" />

Devices/Keyboard/Effects/AbstractEffect.cs

@@ -0,0 +1,37 @@
+using System.Collections.Generic;
+using System.Linq;
+using CUE.NET.Devices.Keyboard.Brushes;
+using CUE.NET.Devices.Keyboard.Keys;
+
+namespace CUE.NET.Devices.Keyboard.Effects
+{
+    public abstract class AbstractEffect : IEffect
+    {
+        #region Properties & Fields
+
+        public abstract IBrush EffectBrush { get; }
+
+        public IEnumerable<CorsairKey> KeyList { get; protected set; }
+
+        public bool IsDone { get; protected set; }
+
+        #endregion
+
+        #region Methods
+
+        public void SetTarget(IKeyGroup keyGroup)
+        {
+            KeyList = keyGroup.Keys.ToList();
+        }
+
+        public abstract void Update(float deltaTime);
+
+        public virtual void OnAttach()
+        { }
+
+        public virtual void OnDetach()
+        { }
+
+        #endregion
+    }
+}

Devices/Keyboard/Effects/FlashEffect.cs

@@ -0,0 +1,123 @@
+using System;
+using System.Drawing;
+using CUE.NET.Devices.Keyboard.Brushes;
+
+namespace CUE.NET.Devices.Keyboard.Effects
+{
+    public class FlashEffect : AbstractEffect
+    {
+        #region Properties & Fields
+
+        public override IBrush EffectBrush { get; }
+
+        // Settings are close to a synthesizer envelope (sustain is different for consequent naming): https://en.wikipedia.org/wiki/Synthesizer#ADSR_envelope
+        public float Attack { get; set; } = 0.2f;
+        public float Decay { get; set; } = 0f;
+        public float Sustain { get; set; } = 0.3f;
+        public float Release { get; set; } = 0.2f;
+
+        public float SustainValue { get; set; } = 1f;
+        public float AttackValue { get; set; } = 1f;
+
+        public float Interval { get; set; } = 1f;
+
+        public int Repetitions { get; set; } = 0;
+
+        private ADSRPhase _currentPhase;
+        private float _currentPhaseValue;
+        private int _repetitionCount;
+
+        #endregion
+
+        #region Constructors
+
+        public FlashEffect(Color flashColor)
+            : this(new SolidColorBrush(flashColor))
+        { }
+
+        public FlashEffect(IBrush effectBrush)
+        {
+            this.EffectBrush = effectBrush;
+        }
+
+        #endregion
+
+        #region Methods
+
+        public override void Update(float deltaTime)
+        {
+            _currentPhaseValue -= deltaTime;
+
+            // Using ifs instead of a switch allows to skip phases with time 0.
+
+            if (_currentPhase == ADSRPhase.Attack)
+                if (_currentPhaseValue > 0f)
+                    EffectBrush.Opacity = Math.Min(1f, (Attack - _currentPhaseValue) / Attack) * AttackValue;
+                else
+                {
+                    _currentPhaseValue = Decay;
+                    _currentPhase = ADSRPhase.Decay;
+                }
+
+            if (_currentPhase == ADSRPhase.Decay)
+                if (_currentPhaseValue > 0f)
+                    EffectBrush.Opacity = SustainValue + (Math.Min(1f, _currentPhaseValue / Decay) * (AttackValue - SustainValue));
+                else
+                {
+                    _currentPhaseValue = Sustain;
+                    _currentPhase = ADSRPhase.Sustain;
+                }
+
+            if (_currentPhase == ADSRPhase.Sustain)
+                if (_currentPhaseValue > 0f)
+                    EffectBrush.Opacity = SustainValue;
+                else
+                {
+                    _currentPhaseValue = Release;
+                    _currentPhase = ADSRPhase.Release;
+                }
+
+            if (_currentPhase == ADSRPhase.Release)
+                if (_currentPhaseValue > 0f)
+                    EffectBrush.Opacity = Math.Min(1f, _currentPhaseValue / Release) * SustainValue;
+                else
+                {
+                    _currentPhaseValue = Interval;
+                    _currentPhase = ADSRPhase.Pause;
+                }
+
+            if (_currentPhase == ADSRPhase.Pause)
+                if (_currentPhaseValue > 0f)
+                    EffectBrush.Opacity = 0f;
+                else
+                {
+                    if (++_repetitionCount >= Repetitions && Repetitions > 0)
+                        IsDone = true;
+                    _currentPhaseValue = Attack;
+                    _currentPhase = ADSRPhase.Attack;
+                }
+        }
+
+        public override void OnAttach()
+        {
+            base.OnAttach();
+
+            _currentPhase = ADSRPhase.Attack;
+            _currentPhaseValue = Attack;
+            _repetitionCount = 0;
+            EffectBrush.Opacity = 0f;
+        }
+
+        #endregion
+
+        // ReSharper disable once InconsistentNaming
+        private enum ADSRPhase
+        {
+            Attack,
+            Decay,
+            Sustain,
+            Release,
+            Pause,
+        }
+    }
+}