public Nullable<double> LuminanceOffset {get;}
Luminance is also referred to as brightness.
The luminance offset is applied by converting the base color from RGB to HSL, then the value of this property to the luminance channel, then converting back to RGB.
Assigning a value of null to this property implies that the associated color has no specific luminance offset.
Target Platforms: Android 4.4+, iOS 8+
Development Environments: Visual Studio 2015+, Visual Studio for Mac Preview, Xamarin for Visual Studio 4.2+