Chapter 0: Preface
Table of Contents
This document (whose browsable version is accessible by using your browser's
"File
Open File" command
on /opt/graphics/common/doc/GAG/Web/index.html) was created to fill a
need that became evident as Hewlett-Packard began to offer multiple
Application Programmer Interfaces (APIs). The situation was this: As HP
created one API
say, Starbase
particular aspects of graphical operation
were noted and diligently explained in the Starbase documentation. However,
some of these aspects were not unique to Starbase, they pertained to graphics
operation in general: they applied to all of our APIs. Therefore,
those users who had HP-PHIGS would be encountering some of the same graphical
questions that were already well-documented in the Starbase documentation.
But HP-PHIGS users wouldn't necessarily have the Starbase
documentation. Are they just out of luck? The same situation occurred with
HP PEX.
Our dilemma was this: do we copy the general-graphics explanations that
already existed in the Starbase documentation, into the documentation for the
other APIs as well? This would mean two, three, or even more virtually
identical copies of the same explanations in different places, requiring
similar changes in each whenever new capabilities or devices were introduced.
And if all documents containing these similar explanations were not reprinted
simultaneously, "current" documents for the various APIs might contradict each
other.
A more elegant solution is: this document. While the API-specific documents
still contain most of their previous contents, the general graphical
information
common to all APIs
was moved here. Examples include:
- X Windows issues: The primary user interface of the workstation, so
that is required whether you use any 3D APIs or not. And if you do, all
APIs interact with X windows, so non-unique X Windows information comes
here.
The above topics, and others as well, are good candidates for a common area.
With this approach, only one copy of the common information need exist, and
revisions can happen in a more timely manner, and at less risk of
contradicting other documents.
Below is a list of the typographical conventions used in this document:
- mknod /usr/include
- Verbatim computer literals are in computer font. Text in this style is
letter-for-letter verbatim and, depending on the context, should be typed
in exactly as specified, or is named exactly as specified.
- In every case...
- Emphasized words are in italic type.
- . . .device is a freen. . .
- New terms being introduced are in bold-faced type.
- . . .the
device_id
. . .
- Conceptual values are in italic type, enclosed in angle brackets. These
items are not verbatim values, but are descriptors of the type of
item it is, and the user should replace the conceptual item with whatever
value is appropriate for the context.