DCL:GRPH2:GRPACK: Higher-Level Control Routines
When GRPH2 uses its packages to draw new figures, these packages are
initialized and the transformation function parameters are set (though changes
with a runtime option is permitted). At the present, initialization is performed
for SGPACK, UZPACK, UUPACK, USPACK, and UMPACK.
GRPACK basically provides routines that correspond to those for "control" and
"normalization transformation" in GRPH1. For example,
there is a routine in GRPACK named grfrm that corresponds to sgfrm.
This routine calls routines such as sgfrm and initializes various
packages at the same time. The initialization procedure includes assigning
"undefined" values to parameters that may be set automatically by
GRPH2 sub-packages. (Actually, values of the internal variables 'RUNDEF' and
'IUNDEF' handled by glpget/glpset
are assigned.) Also, there is a routine named grstrf, which corresponds
to sgstrf. This routine checks whether all necessary parameters for the
normalization transformation have been set (i.e. are not RUNDEF) and calls sgstrf
internally.
The parameters set by GRPACK can be changed by a runtime option. For example, by using the routine gropn which corresponds to sgopn, the specified workstation number can be changed using an runtime option.