From 1b4af74b14d2d3752ecd1bf833f72f0f9ab57ba7 Mon Sep 17 00:00:00 2001
From: Darth Affe <darthaffe@wyrez.org>
Date: Sun, 11 Dec 2016 15:41:22 +0100
Subject: [PATCH] Added gamma-value to brushes to allow a simple color
 correction

---
 Brushes/AbstractBrush.cs | 15 ++++++++++++++-
 Brushes/IBrush.cs        |  6 ++++++
 Helper/ColorHelper.cs    | 17 +++++++++++++++++
 3 files changed, 37 insertions(+), 1 deletion(-)

diff --git a/Brushes/AbstractBrush.cs b/Brushes/AbstractBrush.cs
index 3e9626d..c77f646 100644
--- a/Brushes/AbstractBrush.cs
+++ b/Brushes/AbstractBrush.cs
@@ -2,6 +2,7 @@
 // ReSharper disable MemberCanBePrivate.Global
 // ReSharper disable VirtualMemberNeverOverridden.Global
 
+using System;
 using System.Collections.Generic;
 using System.Drawing;
 using System.Linq;
@@ -34,6 +35,12 @@ namespace CUE.NET.Brushes
         /// </summary>
         public float Opacity { get; set; }
 
+        /// <summary>
+        /// Gets or sets the gamma-value used to correct the colors calculated by the brush.
+        /// Values greater than one will make colors brighter, values less than one will make colors darker. 
+        /// </summary>
+        public float Gamma { get; set; }
+
         /// <summary>
         /// Gets the Rectangle used in the last render pass.
         /// </summary>
@@ -58,10 +65,12 @@ namespace CUE.NET.Brushes
         /// </summary>
         /// <param name="brightness">The overall percentage brightness of the brush. (default: 1f)</param>
         /// <param name="opacity">The overall percentage opacity of the brush. (default: 1f)</param>
-        protected AbstractBrush(float brightness = 1f, float opacity = 1f)
+        /// <param name="gamma">The gamma-value used to correct the colors calculated by the brush. (default: 1f)</param>
+        protected AbstractBrush(float brightness = 1f, float opacity = 1f, float gamma = 1f)
         {
             this.Brightness = brightness;
             this.Opacity = opacity;
+            this.Gamma = gamma;
         }
 
         #endregion
@@ -113,6 +122,10 @@ namespace CUE.NET.Brushes
             // THIS IS NOT A HSB CALCULATION!!!
             float finalBrightness = color.GetHSVValue() * (Brightness < 0 ? 0 : (Brightness > 1f ? 1f : Brightness));
             byte finalAlpha = (byte)(color.A * (Opacity < 0 ? 0 : (Opacity > 1f ? 1f : Opacity)));
+
+            if (Math.Abs(Gamma - 1f) > float.Epsilon)
+                ColorHelper.CorrectGamma(color, Gamma);
+
             return ColorHelper.ColorFromHSV(color.GetHSVHue(), color.GetHSVSaturation(), finalBrightness, finalAlpha);
         }
 
diff --git a/Brushes/IBrush.cs b/Brushes/IBrush.cs
index b831614..1be96ab 100644
--- a/Brushes/IBrush.cs
+++ b/Brushes/IBrush.cs
@@ -29,6 +29,12 @@ namespace CUE.NET.Brushes
         /// </summary>
         float Opacity { get; set; }
 
+        /// <summary>
+        /// Gets or sets the gamma-value used to correct the colors calculated by the brush.
+        /// Values greater than one will make colors brighter, values less than one will make colors darker. 
+        /// </summary>
+        float Gamma { get; set; }
+
         /// <summary>
         /// Gets the Rectangle used in the last render pass.
         /// </summary>
diff --git a/Helper/ColorHelper.cs b/Helper/ColorHelper.cs
index d03e20b..8a6e842 100644
--- a/Helper/ColorHelper.cs
+++ b/Helper/ColorHelper.cs
@@ -99,6 +99,23 @@ namespace CUE.NET.Helper
 
         #endregion
 
+        #region Color-Correction
+
+        /// <summary>
+        /// Corrects the color using the specified gamma.
+        /// </summary>
+        /// <param name="color">The color to correct.</param>
+        /// <param name="gamma">The gamma value to apply.</param>
+        public static void CorrectGamma(CorsairColor color, float gamma)
+        {
+            double value = 1.0 / gamma;
+            color.R = GetIntColorFromFloat((float)Math.Pow(color.GetFloatR(), value));
+            color.G = GetIntColorFromFloat((float)Math.Pow(color.GetFloatG(), value));
+            color.B = GetIntColorFromFloat((float)Math.Pow(color.GetFloatB(), value));
+        }
+
+        #endregion
+
         #region RGB/HSV conversion
         // https://en.wikipedia.org/wiki/HSL_and_HSV