CenterStage Object Class:  DataFromSurface
Subclass of:  Surface
Requires a reference to a Surface object

The DataFromSurface class provides a means of using the data already
computed by another Surface object.  One reason to do this is to change the
coloring or domain style without having to recompute the data.  Another is
to make a ShowMe checkbox that can be used to turn the surface on and off
without recomputing it (or any other objects linked to it).  To do this,
make a Surface object that has its OBJECT/SHOW menu set to NEVER, and then
create a DataFromSurface object that links to it and has the CheckBox and
ShowMe directives.  When the DataFromSurface object is first shown, it will
force the Surface object to compute the data, and then the DataFromSurface
object will be able to use that data whenever it is shown, without
recomputing it.

The DataFromSurface object has no non-standard directives.