A mask determines the part of the target image that is visible to end-users. By default, the mask is proportionally stretched to fit the image's bounds. Using the MaskLayoutMode property, you can change how the mask is positioned relative to the image.
For masks of the Circle and RoundedRect types (see MaskType), setting the MaskLayoutMode property to BottomCenter, BottomLeft, BottomRight, MiddleCenter, MiddleLeft, MiddleRight, TopCenter, TopLeft or TopRight has no visual effect unless you modify the Size property.
The Offset and Margin properties allow you to shift the mask relative to the image.