Specifies the coordinate system used by a Brush.
The coordinate system is relative to a bounding box: 0 indicates 0 percent of the bounding box, and 1 indicates 100 percent of the bounding box. For example, 0.5, 0.5 describes a point in the middle of the bounding box, and 1, 1 describes a point at the bottom right of the bounding box.
The coordinate system is not relative to a bounding box. Values are interpreted directly in local space.
Note that the bounding box concept for the RelativeToBoundingBox value depends on the property with which this enumeration is used. For LinearGradientBrush, the bounding box is left to right in the full brush application area. For RadialGradientBrush, the bounding box is centered on the radiant center and encompasses the ellipse that the brush defines.
A value of Absolute indicates that the LinearGradientBrush coordinates are expressed in pixels.
The MappingMode of a LinearGradientBrush or RadialGradientBrush does not influence how the Offset values are interpreted. Regardless of mapping mode, the offset is always interpreted as a factor between 0 and 1 along the vector that defines the gradient.