Gets or sets an opacity mask, as a Brush implementation that is applied to any alpha-channel masking for the rendered content of this element. This is a dependency property.
Assembly: PresentationCore (in PresentationCore.dll)
Metadata properties set to true
The most typical Brush for this purpose is an ImageBrush, which can be used for a variety of photo masking techniques such as a vignette. But any defined Brush (such as LinearGradientBrush) can be used.
In Extensible Application Markup Language (XAML), this property value can use an inline syntax that is specific to each implementation of the Brush abstract class. For more information, see Painting with Solid Colors and Gradients Overview.