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DCL:GRPH1:SWPACK: Machine-Dependent Routines

7.1 Summary

The SWPACK is a group of machine-dependent routines in the GRPH1 library at the lowest level. In the SWPACK, only the standards for the higher interfaces are defined, and the actual operations and the internal structures are device-dependent.

There are the "basic functions" and the "extended functions" in the SWPACK. The basic functions can be executed (or assumed as possible) by all devices,  but the extended functions may not be executable in some devices.

• Basic Functions
  • Line Functions (capacity to change either the line width or color.)
• Extended Functions
  • Hard Fill Function (Half-tone dot meshing by hardware)
  • Image Display Function (Drawing by dots)
  • Pointing Device (such as mouse)

A higher routine may not be able to use extended functions, so coating must be performed. To check whether these functions can be used, use the inquiry routines of SWPACK.

On the GRPH1 level, the switching between line width and color is carried out depending on the capacity of the device. For devices that cannot perform hard fill, the fill routine automatically performs soft fill.

As there are no alternative routines for the image display and pointing functions, the user must be careful when using them.

In the SWPACK, the machine-dependent internal variable can be inquired/changed by swpget/swpset (integer variable, floating-point variable, logical variable) and swcget/swcset (character variable). However, the internal variables handled by swpget/swpset and swcget/swcset, are all read only once when the device is opened and are not inquired again, so swpset and swcset must be called before calling sgopn.

Section 7.8 provides an explanation of the internal variables for the graphics output devices provided in the standard DCL library (X-server, postscript, Tek terminal). The internal variables defined are system-dependent.