Raster Graphics

the almost unlimited chances for advanced hardware realizations offered by VLSI techniques; and perhaps most important the acceptance of raster graphics devices in a steadily growing number of applications. The last point includes the incorporation of graphics techniques in video based services like p?Ts interactive vidoetex. In a sense, raster graphics returns after years of ripening back to the starting point, that is television, and offers its know-how in interactive techniques and high resolution image generation. The development of High Definition Television (HDTV), covered in the last contribution of this series on raster graphics, is an important result of this mutual fertilization. It can be a step towards the integration of the &ermt forms of pictorial communication (i.e., graphics, TV, facsimile) at the workstation level (to appear in the next issue of Computer Gruphics Forum). One aspect of generating realistic pictures in my opinion neglected for a long time is the user interface. It is well known that in most cases the first output of a picture docs not meet the designer‘s expections. This is due to the di.tEculties of correct specification of viewing and lighting conditions, colours and, last but not least, the non-linear performance of display devices. There fore, several iterations including user interactions are normally required. In the first paper, JJ. van Wijl, F.W. Jansen, and W.F. Bronsvoort describe solutions to some issues in designing user interfaces to 3D raster graphics.