20.1.5.2 backdrop

This element defines a plane in which effects, such as glow and shadow, are applied in relation to the shape they are being applied to. The points and vectors contained within the backdrop define a plane in 3D space.

[Example: Consider the following image as an explanation of the backdrop plane definition:

In this image we see a plane being defined by an anchor point, the vector normal to the face of the plane and a vector pointing up in relation to the plane. end example]

[Note: The W3C XML Schema definition of this element’s content model (CT_Backdrop) is located in A.4.1. end note]