Information technology - Computer graphics - Interfacing techniques for dialogues with graphical devices (CGI) - Functional specification - Part 1: Overview, profiles, and conformance

This document is the first of a family of standards. ISO/IEC 9636 establishes the conceptual model, functional capability, and minimum conformance requirements of the Computer Graphics Interface (CGI). It specifies design requirements for encodings of the CGI. ISO/IEC 9636 defines a set of CGI functions that is expected to satisfy the following needs of a majority of the computer graphics community:(a) provide an interface standard for computer graphics software package implementors;(b) provide an interface standard for computer graphics device manufacturers and suppliers;(c) provide an inquiry and response mechanism for graphics device capabilities, characteristics, and states;(d) provide a standard graphics escape mechanism to access non-standard graphics device capabilities; and(e) allow for future functional extension of the CGI.In addition to the CGI functionality, device classes, and Foundation and Constituency Profiles are defined. The device classes included in the CGI are output (OUTPUT), input (INPUT), and output/input (OUTIN). Profiles allow subsets of the CGI functions and features to be defined to suit particular well-identified groups of users. There is also provision for Constituency Profiles to be registered after ISO/IEC 9636 is published. The Computer Graphics Interface (CGI) is a standard functional and syntactical specification of the control and data exchange between device-independent graphics software and an implementation of a CGI Virtual Device. The syntax of the CGI, presented in ISO/IEC 9636, is an encoding-independent and binding-independent specification. Any similarity of the examples or function specifications to a particular encoding technique or language is coincidental unless explicitly stated otherwise. The functions specified provide for the representation of a wide range of two-dimensional pictures and for control over their display on a wide range of graphics devices. The functions are split into groups that perform device and CGI session control, specify the data representations used, control the display of the picture, perform basic drawing actions, control the attributes of the basic drawing actions, acquire data from input devices, and provide access to non-standard device capabilities. This part of ISO/IEC 9636 gives an overview of ISO/IEC 9636, explains the relationship between its parts and their relation to other standards, describes a reference model for graphics systems, and defines certain Foundation and Constituency Profiles. ISO/IEC 9636-2, ISO/IEC 9636-3, ISO/IEC 9636-4, ISO/IEC 9636-5, and ISO/IEC 9636-6 specify the CGI functions for different functional areas using an abstract notation. ISO/IEC 9637 and ISO/IEC 9638 define standard data stream encodings, procedural library bindings, and single entry point procedural bindings of the CGI.

ISO/IEC 9636-1:1991