Added CIE Lab Gamma Equation (#651)

keywords.txt

@@ -722,6 +722,7 @@ NeoTopology	KEYWORD1
 NeoRingTopology	KEYWORD1
 NeoTiles	KEYWORD1
 NeoMosaic	KEYWORD1
+NeoGammaCieLabEquationMethod	KEYWORD1
 NeoGammaEquationMethod	KEYWORD1
 NeoGammaTableMethod	KEYWORD1
 NeoGamma	KEYWORD1
@@ -817,6 +818,7 @@ CircularOut	KEYWORD2
 CircularInOut	KEYWORD2
 CircularCenter	KEYWORD2
 Gamma	KEYWORD2
+GammaCieLab	KEYWORD2
 Map	KEYWORD2
 MapProbe	KEYWORD2
 getWidth	KEYWORD2

src/internal/NeoEase.h

@@ -312,4 +312,16 @@ public:
     {
         return pow(unitValue, 1.0f / 0.45f);
     }
+
+    static float GammaCieLab(float unitValue)
+    {
+        if (unitValue <= 0.08f)
+        {
+            return unitValue / 9.033f;
+        }
+        else
+        {
+            return pow((unitValue + 0.16f) / 1.16f, 3.0f);
+        }
+    }
 };

src/internal/NeoGamma.h

@@ -40,6 +40,20 @@ public:
     }
 };
 
+// Alternative equation to provide at least one official model for specific LEDs
+class NeoGammaCieLabEquationMethod
+{
+public:
+    static uint8_t Correct(uint8_t value)
+    {
+        return static_cast<uint8_t>(255.0f * NeoEase::GammaCieLab(value / 255.0f) + 0.5f);
+    }
+    static uint16_t Correct(uint16_t value)
+    {
+        return static_cast<uint16_t>(65535.0f * NeoEase::GammaCieLab(value / 65535.0f) + 0.5f);
+    }
+};
+
 struct NeoGamma16LowHint
 {
     uint8_t pos;