The PL GRAPHICS SYSTEM is a complete hardware and software package for use with the BBC Model B Microcomputer, offering a wide range of facilities for creating and handling visual images. The package consists of the "GRAPHIC DIGITISER", incorporating a 256mm x 205mm, graphed tracing pad, the software - on tape or disc - containing five programs, instruction manual, key card, quick reference card and exercise diagrams.

The system has been carefully structured so that users can achieve professional standards of design without specialist computing skills. Ease-of-use and speed-of-results have been the dominant features of the system, which has been widely adopted in education and commerce.

The hardware component consists of the P.L Digitiser, a graphics tablet designed on a pantograph principal and employing potentiometric transducers. Both electrical and mechanical components have been precision engineered so that visual designs

placed on the tracing area can be faithfully copied. The moving parts of the mechanism are totally enclosed in a robust case of laminated material, and each Digitiser is calibrated at the factory and requires minimal adjustment during use. The Digltiser is plugged into the analogue part of the BBC Microcomputer and requires no external power supplied. The software support for the Digitiser makes it a powerful tool for exploiting the full potential of the graphics facilities of the BBC Microcomputer. There is full control over the colour and texture of lines with the minimum of manipulation of both the Digitiser and the computer keyboard. A special feature provides a system for designing character-graphics with "turtle" plotting and animation.

Pictures are created in the system by either copying a prepared design placed on the tracing area, or by free design on the screen; in both cases the Digitiser probe is used to manoeuvre precisely a flashing cursor around the screen. Messages are displayed on the screen which prompt the user for the next input required from the Digitiser. The Control Program handles information from the tracing area In a way which minimises the number of probe input locations and keyboard entries. This is achieved by the provision ot a range of plotting aids that enable the user to concentrate on a limited number of key features In the design. As a design develops, the Control Program stores data in a specially compacted form of coding which makes the most economic use of the computer's available memory. Through the powerful editing facilities in the system, this data is available for total recall. This Is a distinctive feature of the P.L. GRAPHICS SYSTEM making it a genuine Computer-Aided-Design package. In whole or in part, images may be modified and manipulated with extraordinary ease. Shapes and patterns can be labelled in the data-coding making them available for instant recall on demand. Picture data can be easily saved on cassette or

disc file, and programs are provided for the loading of data and picture reconstruction, either as a self-contained package or In the environment of the user's own programs. The filing and editing facilities together provide a powerful system for creating libraries of specialised patterns, shapes and symbols which are easily recalled and incorporated into new designs.

MAIN FEATURES ARE:

* CONTROL PROGRAM WITH WIDE RANGE OF INSTRUCTION BLOCKS

Instruction blocks enable boxes and circles to be constructed from two probe positions, filling area with chosen colour, painting area with colour or shading, drawing of irregular shapes, outlining in different colour and varying line thickness, creating lines in horizontal, vertical or angled modes with parallel lines In repeat or multiple repeat styles In selected thickness. Special routines for plotting circular arcs and for the animation and multiple plotting of text.

* COMPLETE EDITING FACILITIES Mistakes can Instantly be erased and rectified with random and sequential access to stored picture data which may be easily revised, corrected and modified.

* IMAGE MANIPULATION

Images may be reflected, rotated, moved, scaled, duplicated, compressed and extended.

* CURSOR UTILITY CALLS

The probe positions displayed on screen can be justified vertically and horizontally to aid rapid joining of lines. Additionally vertical, horizontal and perspective guide lines can be constructed.

* ACCURACY/SPEED

Probe position is continuously displayed on the screen and fidelity of image to original drawing is excellent. Completed images .can be recalled from file and dumped to the screen in seconds.

* STORAGE

Pictures may be saved on cassette or disc file or dumped to printer.

* USER-DEFINED CHARACTER PROGRAM

Freedom of character design means shapes and symbols can be created in very fine detail. Characters may be plotted many times over, clustered, mixed with normal text characters, used in animation effects, "TURTLE" control

* PRINTER DUMP PROGRAM The software contains programs enabling images to be   dumped to the Epson MX. RX and FX. Walters, Seikosha. Acorn and Tandy.

* DISPLAY PROGRAM

The main control program contains a 'Display' program which enables the user to freely mix visuals In their own programs.

* SELECT PROGRAM

Enables user to store pictures on separate disc or tape for easy recall.

* FULL COLOUR/RESOLUTION The range of colour facilities offered by the BBC Micro in Modes 4 and 5 are easily handled by the P.L. GRAPHICS SYSTEM. In high and medium resolution.