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
All Plots have this attribute.
The Plot3D class
ignores this attributes, assuming a value of zero.