PREMO is a major new ISO/IEC standard for graphics and multimedia, which addresses many of the concerns that have been expressed about existing graphics standards. In particular, it addresses the issues of configuration, extension, and interoperation of and between PREMO implementations. This paper gives an overview of PREMO and highlights its most significant features.

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Several members of the American National Standards Institute (ANSI) Technical Committee X3H3 on Computer Graphics will present current issues of the standardization effort. The focus of the discussion will be the technical content of these issues.The purpose of the panel discussion is to encourage technical dialogue between X3H3 participants and interested parties outside of X3H3. To that end, the presentations will describe major areas of concern, avenues of attack, and proposed solutions.

Raster scanned graphics terminals provide several features not found in standard line drawing displays. Among them are area fill and an extensive color palette. Hardware support for such functions is becoming cost effective and available in a variety of forms. What is now needed is high level, device independent software that assists in the generation of and interaction with these terminals. To accomplish this, a project has been undertaken jointly by Sandia Laboratories, Purdue University, and MEGATEK Corporation to integrate solid image capabilities into the Graphics Compatibility System, GCS. GCS is a widely used, general purpose calligraphic graphics package. Due to the similarity of the GCS model to that of the GSPC Core System, GCS provides a timely test bed for solid image extensions to a line drawing package. This paper will summarize the capabilities being implemented, the method and motivation behind each function, and suggestions for further work.

An algorithm is presented which clips on a non-rotated viewport positioned anywhere on the viewport plane relative to the viewing vector. This is a generalization of the traditional three-dimensional clipping algorithm in which the viewing vector intersects the viewport at its center. This traditional algorithm is shown to be a special case of the general algorithm. Also shown is that both orthogonal box clipping and perspective pyramid clipping can be accomplished using the same algorithm with only a slight increase in complexity. Finally, the ability to perform switch-controlled hither and yon plane clipping is described. It should be noted that with this general clipping algorithm no separate clipping operation is required for two-dimensional operations since they can be handled as an orthogonal projection from an arbitrary default Z-plane onto the viewport plane.