Overview
ISO/IEC 11072:1992 - Computer Graphics Reference Model (CGRM) defines a conceptual framework for computer graphics standards. It describes a set of generic concepts and their relationships intended to guide the development, comparison and integration of current and future computer graphics standards. The CGRM is abstract: it structures graphics systems into levels, data stores and processing operations, and defines how a graphics system interfaces with applications, operators and external metafiles.
Key Topics
- Five environments: construction, virtual, viewing, logical and realization - each representing an abstraction level between application and operator.
- Data elements: composition (model, scene, picture, graphical image, display), collection store, aggregation store, token store (instruction, directive, selection, information, lexeme stores), and environment state.
- Processing elements: absorption (preparation, production, projection, completion, presentation), emanation (utilization, generation, elevation, abstraction, accumulation), distribution, assembly and manipulation.
- Input/Output primitives: atomic units for graphical output (output primitives) and input (input tokens), with properties and geometric transformations.
- External interfaces: the application interface (to the construction environment), the operator interface (to the realization environment), and metafile interfaces for data capture and audit trails.
- Purpose and limitations: used to verify/refine graphics requirements, identify standards needs, develop models and define architecture. Not an implementation specification, language binding, encoding format, nor a conformance test suite.
Applications and Users
ISO/IEC 11072:1992 is primarily useful to:
- Standards bodies and working groups (e.g., ISO/IEC JTC 1 SC24) when designing consistent, interoperable graphics standards.
- System architects and API designers planning the architecture of graphics subsystems, windowing interfaces, or metafile interchange.
- Interoperability and integration engineers who need to map between different graphics standards or verify how existing standards relate conceptually.
- Researchers and technical managers exploring high-level models for rendering, input handling, and graphics data interchange.
Practical uses include defining the architecture of new graphics standards, comparing standards, identifying external interface requirements (operator/application/metafile), and providing a neutral vocabulary for multidisciplinary integration (imaging, window systems, product data exchange).
Related Standards
Annex A of ISO/IEC 11072 references existing graphics standards for alignment, including:
Keywords: ISO/IEC 11072:1992, Computer Graphics Reference Model, CGRM, computer graphics standard, environments, data elements, processing elements, output primitives, input tokens, application interface, operator interface, metafile.
