Add simple gamma function

utils/colors_helper.py

@@ -3,6 +3,7 @@
 .. moduleauthor:: `Marie FETIVEAU <github.com/mfe>`_
 
 """
+import math
 
 
 def xy_to_XYZ(xy, Y=1):
@@ -22,3 +23,33 @@ def xy_to_XYZ(xy, Y=1):
     X = (x*Y)/y
     Z = ((1-x-y)*Y)/y
     return [X, Y, Z]
+
+
+def lin_to_gamma(self, value, gamma):
+    """Simple lin to Gamma function
+
+    Args:
+        value (float): input value
+
+        gamma (float): gamma value
+
+    Returns:
+        .float
+
+    """
+    return math.pow(value, 1/gamma)
+
+
+def gamma_to_lin(self, value, gamma):
+    """Simple gamma to lin function
+
+    Args:
+        value (float): input value
+
+        gamma (float): gamma value
+
+    Returns:
+        .float
+
+    """
+    return math.pow(value, gamma)