The GraPL Engine – History and Heritage

1992 - the simplest thing that could possibly work

PostScript is a much-misunderstood technology. Most of the world simply thinks of it as yet another printer-driver - and a slightly weird one at that - but in fact it is a powerful general-purpose programming language which is ideal for making high-level descriptions of text and vector drawings. It is also totally device-independent so anything you write in 1992 for your 300dpi laser will work the same (only better) on the best hardware you can find today. Stage-1 was to look hard at the charts I wanted and to see them as collections of function-calls to handle arrays of text, tick-marks, markers and filled regions.

The basic platform which I used to implement “Rain” was therefore a collection of PostScript macros, which I could run through GoScript and have printed on my HP Deskjet at a quality which still astonishes me. For home use, this was almost a complete solution, but I made the mistake of showing some of the charts to my colleagues and immediately sparked a demand for these charts to be displayed on screen, and printed on 'ordinary' printers.

1994 - implementing a chart viewer

In a sense I had made life easy for myself by expressing all the variety and complexity of the available charts as a rather small collection of PostScript macros. All I needed to write was a very basic PostScript interpreter which parsed out the macros and called appropriate functions to render the lines and text on the screen. Under DOS (at EGA resolution, remember) the results were not pretty but the charts were very usable and soon the engine was well-established in a variety of factory-information systems. It quietly developed more chart types, and was shown at a few OR conferences and British Computer Society meetings and gradually built up a following amongst researchers and statisticians. Specialist charts like the BoxWhisker were prototyped for me at the European Business Management School in Swansea, where “Rain” formed part of the software suite used for statistics teaching.

1996 - first commercial implementation

This was about the point where you could assume that 'everyone' was running Windows, so I rewrote the DOS-based viewer for the two major APL platforms (Dyalog APL and APL+Win from Cognos) and began to sell the engine to fellow APL developers as “RainPro”. It is interesting that it made the strongest impact in the Scandinavian countries, particularly in Finland - I suppose that the people there have a national reputation for caring deeply about good design, so my focus on clear presentation and accurate typography was just what they most appreciated. “RainPro” also gives them the power to make charts like this:

At a winter seminar in Helsinki in February 2000, we were told “You are the industry standard in Finland”, which was a most gratifying accolade.