Overview
ISO/IEC 9636-5:1991 is Part 5 of the CGI (Computer Graphics Interface) functional specification. It defines the interface functions for obtaining graphical and non-graphical input from CGI Virtual Devices of class INPUT or OUTIN, and for echoing input operations on separate virtual devices. The standard describes device-independent mechanisms to control logical input devices (LIDs), collect input values, manage echo output, and query device capabilities and states.
Key topics and technical requirements
- Logical Input Devices (LIDs): LIDs encapsulate a measure, state information and associated triggers. The standard formalizes initialization, allocation and deallocation of LIDs and how clients tailor their characteristics.
- Input methods: Support for multiple input methods including Request, Sample, Echo Request, and Event input methods. Functions control request flow, sampling state, and echo-tracked requests.
- Echoing and echo output: Functions to initialize, release and control echo entities and to perform echo output updates so values originating from one device can be shown on another.
- Event handling: Event queue control (initialize, release, enable/disable events, flush, await, dequeue, transfer) enabling concurrent processing of input events while performing graphical output.
- Inquiry functions and state lists: Comprehensive inquiry APIs to retrieve input capability tables, class-specific device capabilities (locator, stroke, pick, string, raster, etc.), lists of supported echo/prompt/acknowledgement types, and live device/echo states.
- Data types and records: Defines the data types returned by input functions and the format of echo and device data records.
- Example function families: REQUEST , SAMPLE , INITIALIZE ECHO REQUEST, ENABLE/DISABLE EVENTS, INITIALIZE ECHO OUTPUT, UPDATE ECHO OUTPUT, INQUIRE INPUT CAPABILITY, INQUIRE LOCATOR CAPABILITIES.
Applications and who uses it
ISO/IEC 9636-5 is intended for:
- Graphics system and toolkit developers implementing device-independent input layers.
- Device driver and virtual device implementers who need standardized input/echo semantics.
- CAD/CAM, visualization and HCI application authors requiring precise, interoperable input handling and echoing across devices.
- Middleware and standards compliance engineers ensuring interoperability between graphics clients and virtual devices.
Benefits include consistent, portable input handling across diverse graphical devices, explicit event/echo control for interactive applications, and standardized inquiry interfaces for capability discovery.
Related standards
Keywords: ISO/IEC 9636-5, CGI, computer graphics, graphical input, logical input device, echoing, virtual device, request/sample input, event input, input inquiry.
Open preview (PDF)Information technology — Computer graphics — Interfacing techniques for dialogues with graphical devices (CGI) — Functional specification — Part 5: Input and echoing
