RAL-GKS release 1.11 is now available on the Cray X-MP. This release is a full implementation of the International standard version 7.4 to level 2b. Devices supported on the Cray by this release are: Tektronix 4010, 4014, 4207, Sigmex 5600, 5400, Tektronix emulators, Calcomp plotter, CGM metafiles, GKS metafiles and targeted GKS metafiles Note: All terminal drivers support output only. At the same time the HARDCOPY machine in VM/CMS has been improved so that it can now handle much larger metafiles particularly on the Xerox 4050. This version will initially be available using the NEW procedure ie. NEW,ID=$GKS.
In a short time this version will become the default version of GKS, so all users are urged to use this version. Programs using the old version of GKS (version 0.11) will need to modify their programs. Changes made include: extra parameter needed for GOPKS; negative numbers are used for Hatch style indices. Text Font indices and GDP identifiers; GCA parameters have changed. See GKS74 LISTING on USDOC 193 for full details or contact RAL Graphics Group for advice.
CGM (Computer Graphics Metafile) is an ISO Standard for the storage and transmission of pictures. The CGM differs from GKS metafiles in that the former stores each picture independently whilst the latter is a record of a GKS session. This means that it is easy to select frames at random from a CGM which is not possible with a GKS metafile.
The standard defines three types of encoding:
RAL-GKS version 1.11 is now able to offer CGM character encoded metafiles as well as GKS metafiles. CGM has been shown to be around 20-30% the size of the corresponding GKS metafile, which has advantages in storing and transmission over the network. CGM is also accepted by HARDCOPY (for printing on the Xerox 4050 laser printer, Versatec 9242 electrostatic colour plotter or IBM 4250 electro-erosion printer) and is now the preferred metafile format for this service machine. CGM metafiles can be viewed on the attached Iris workstation, and is the only format that the forthcoming RAL Video Facility will accept directly.
The HARDCOPY command in COS will now dispose a CGM but the keyword CGM must be added to the Command line or the dataset name may be DN = CGM.
Also because CGM is an International Standard it will be readable by other conforming graphics packages. In the near future UNIRAS will support CGM. whereas GKS metafiles have been found to be different in various GKS implementations and not necessarily readable.
Separate Workstations are provided to produce GKS metafiles targeted for a particular HARDCOPY device and size. Only GKS metafiles are produced at present, but in future these will become CGMs. The following Workstations are currently supported together with their forms codes.
| Wkstn | Form | Description |
|---|---|---|
| 900 | XA4 | Xerox 4050 A4 portrait |
| 1160 | VA0 | Versatec A0 portrait |
| 1161 | VA1 | Versatec A1 portrait |
| 1162 | VA2 | Versatec A2 portrait |
| 1163 | VA3 | Versatec A3 portrait |
| 1164 | VA4 | Versatec A4 portrait |
| 1165 | VA5 | Versatec A5 portrait |
| 1170 | VA0L | Versatec A0 Landscape |
| 1171 | VA1L | Versatec Al Landscape |
| 1172 | VA2L | Versatec A2 Landscape |
| 1173 | VA3L | Versatec A3 Landscape |
| 1174 | VA4L | Versatec A4 Landscape |
| 1175 | VA5L | Versatec A5 Landscape |
| 1176 | VSQF | Versatec 10in Square for foils |
| 1177 | VLSQ | Versatec Largest Square 40in × 40in |
| 1178 | VLPP | Versatec Largest Plot 40in × 160in Portrait |
| 1179 | VLPL | Versatec Largest Plot 160in × 40in Landscape |
| 1180 | VB0 | Versatec BO Portrait |
| 1181 | VB0L | Versatec BO Landscape VLPL - Largest Plot 160in × 40in Landscape |
| 1182 | VB1 | Versatec Bl Portrait |
| 1183 | VB1L | Versatec Bl Landscape |
| 1480 | E | IBM 4250 - 297mm × 297mm |
The advantage of using one of these workstations is that it is an Output workstation, rather than a Metafile workstation, which knows the device capabilities. This means that GKS Inquire functions give results that can be used within the program.
