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diff --git a/info/digests/texline/no8/bcs.display b/info/digests/texline/no8/bcs.display new file mode 100644 index 0000000000..53ae1fef8c --- /dev/null +++ b/info/digests/texline/no8/bcs.display @@ -0,0 +1,149 @@ +\centerline{\bf BCS Displays Group} +\medskip +\noindent +The programme for the BCS Displays Group meeting +held at the Rutherford Appleton Laboratory ({\sc ral}) on +October 26th sounded rather close to what I would from the +BCS Electronic Publishing Group. The meeting was rather +grandly titled `Interactive Documents: Today and Tomorrow' +and described as an `International State of the Art +Seminar'. + +The first talk was from Angela Scheller on `Graphics in +Document Standards', a popular topic these days, perhaps +as a reaction to the apparent ease with which graphics +are pasted into your average dtp package. Why should they +have all the fun? Here the accent was on `standards' +(real, {\sc iso} standards, not the {\it de facto} ones). +The two document standards which were examined here were +\sgml\ and {\sc oda} (Office Document Architecture). Of +course, there are other `standards' or quasi-`standards' +like telex, telefax\slash facsimile, teletext, {\sc +ccitt} and {\sc ecma}. There is a bit of politicking +going on at the moment between \sgml\ and {\sc oda}, due +partly to their origins (\sgml\ has its origins in +publishing, and {\sc oda} in computer vendors). {\sc oda} +is claimed to be an `open system'. I'm still waiting for +a clear and concise description of {\sc oda}, but the +points I gathered here were that it involved a +hierarchical structure, with defined inter-relationships; +it supported the notion of logical views and layout views +(conceptually orthogonal); and that it allowed +interchange between different systems. When {\sc oda} +handles graphics, it does so with respect to other +standards, in one of three modes: character based, +raster based, and geometric. Obviously~(?) the most +powerful mode is geometric, where {\sc cgm} is considered +the standard. Clearly there are limitations, but most are +due to the degree to which the standards themselves have +evolved: areas like colour\slash grey scale, moving +images, business graphics, 3D, {\sc cadcam} and maps +still need to be incorporated, beside image overlay, +handling of non-rectangular areas, and also `external +references' (e.g.~images from a picture database). + +\sgml\ offers a different approach. While graphics in +{\sc oda} have limited functionality, but are (or should +be) usable in open systems, graphics in \sgml\ have +unlimited functionality, but only within special +applications environments. In \TeX\ we could contrast +this with the \LaTeX\ picture environment (which offers +limited functionality) over all systems (`open'), and the +use of |\special|s, which have unlimited functionality, +but are system specific. One of \sgml's interesting +features is its `let-out' clause, where it can allow part +of a document to be coded in a non-`standard' ({\it sensu +ISO\/}) way. The usual example is maths, where \sgml\ +usually hands over to \TeX, but here the appropriate +example is some alternative graphics language or system. + +John Harris made some interesting observations on `Demand +Printing': his main objective was to give some +explanation of why demand publishing had not mushroomed. +He presented a vision of bookshops which stocked +hundreds\slash thousands of titles which would then be run +off on the local laser printer, stitched, bound, +dust-jacketed, and placed in the customer's hands, all +within a few minutes. At last, \PS\ reared its head. Harris +concentrated on the fact that \PS\ is a common {\it de +facto} standard, pointing out that it was just what the +record industry had been waiting for (alluding +to one of the examples in the {\sl Cookbook\/}). But he +felt that \PS\ offered us too much: text is essentially +orthogonal, and therefore \PS's capability to skew and +rotate text was usually redundant. He argued that \PS\ +solved many problems we didn't know we had. The key +difficulty for demand publishing was speed and cost. +Taking a minimum desirable throughput at 200\,ppm, at +300\,dpi resolution this comes out at about 3\,Mbytes/sec +transmission speed. For bulk printing a 10-fold +improvement was needed. The rip (raster image processor) +could be speeded up, for example by using Transputers +(there is already a \PS\ clone typesetter which uses +Transputers, and is substantially faster than your average +Linotron rip). But technological changes are also needed, +like continuous paper rolls. + +Although I enjoyed the knockabout with \PS, I was left +doubting whether demand publishing was ever +likely to come about, and that even if it did, it +wouldn't make books any cheaper. + +Crispin Goswell of {\sc ral}, gave the paper I had been +waiting for, `\PS\ in the real world'. I'm not convinced +that {\sc ral} is quite my notion of the real world, +but they have done a great deal with \PS. I recall +a BCS-EP meeting some years ago where someone from +{\sc ral} described early encounters with the +language. Goswell has written a public domain display +\PS\ for the Sun workstation which was shown at the +meeting. This facility goes a long way to resolving one of +the persistent problems with \PS\ --- the lack of +screen preview. I find development work with \PS\ a +nightmare. An aside: how is it that \PS\ is wonderful, and +has been embraced by all my user-% + friendly {\it wysiwyg\/} +chums, despite its obvious unfriendliness, while \TeX\ +remains an anathema to them: could it be something to do +with marketing? + +Goswell's talk was extremely competent, and neutral. +Fortunately here was someone who knew enough about \PS\ +to know its strong and weak points. One of the items he +covered was the problem of device independence. In +theory, sending your \PS\ file to a laser printer, then to +a typesetter should only change the resolution --- the +document should look the same, only better. +Unfortunately, as we all (?) know, this is not always the +case. Rules in particular can change their appearance; +memory usage is different in different rips (i.e.~your +pages may not print at all), and of course the fonts you +think you have used may not be available. Most \PS\ users +will also have encountered the `preamble' problem --- and +will know that there are lots of different releases of +the \PS\ software for printers, all with different bugs +(Let's ignore the clone problem for now.) + +Looking at \PS\ as a programming language, he pointed out +that it is a plain text language -- you can read it --- +it is complete, and it really is a language, not data. As +a programming language it offers extensibility: Goswell +saw no reason why \PS\ could not offer non-linear font +scaling (a charge often levied against it). But he also +noted that the language did encourage hacking, that it +could be hard to read, and was difficult to debug --- +consequences of the dynamic binding of the language and +the ability to redefine anything whenever you pleased. +Portability was generally good, although there were +problems with manufacturer-specific extensions (as +usual), and with fonts. + +This was very useful, evenly balanced and informative +talk which may have swept away some of the +misunderstandings and misconceptions which surround \PS. + +There were three other talks, from Heather Brown, Wendy +Hall, and J\"urgen Sch\"onhut, but none were \TeX-relevant. +\smallskip +\rightline{\sl Malcolm Clark} + |