ONORM EN 28632-1-1992 信息处理系统．计算机图形学．图象描述信息的存储与传递用元文件．功能规格
Information processing systems - Computer graphics -Metafile for the storage and transfer of picture description information - Functional specification
ISO 8632 provides a file format suitable for the storage and retrieval of picture description information. The file format consists of an ordered set of elements that can be used to describe pictures in a way that is compatible between systems of different architectures and devices of differing capabilities and design.
The elements specified provide for the representation of a wide range of pictures on a wide range of graphical devices. The elements are split into groups that delimit major structures (metafiles and pictures), that specify the representations used within the metafile, that control the display of the picture, that perform basic drawing actions, that control the attributes of the basic drawing actions and that provide access to non-standard device capabilities.
The Metafile is defined in such a way that, in addition to sequential access to the whole metafile, random access to individual pictures is well-defined; whether this is available in any system that uses ISO 8632 depends on the medium, the encoding and the implementation.
In addition to a functional specification, three standard encodings of the metafile syntax are specified. These encodings address the needs of applications that require minimum metafile size, minimum effort to generate and interpret, and maximum flexibility for a human reader or editor of the metafile.
This part of ISO 8632 describes the format using an abstract syntax. The remaining three parts of ISO 8632 specify three standardized encodings that conform to this syntax: part 2 specifies a character encoding that conforms to the rules for code extension specified in ISO 2022 in the category of complete coding system; part 3 specifies a binary encoding; part 4 specifies a clear text encoding.