This attribute selects the functions which are used to draw graphics by the Plot class. If it is zero, then the functions in the graphics interface selected at link-time are used (see the ast_link script). Otherwise, functions registered using astGrfSet are used. In this case, if a function is needed which has not been registered, then the function in the graphics interface selected at link-time is used.

The default is to use the graphics interface

Plot

Plot3D

• The value of this attribute is not saved when the Plot is written out through a Channel to an external data store. On re-loading such a Plot using astRead, the attribute will be cleared, resulting in the graphics interface selected at link-time being used.