FRANCO FREY TAKES A LOOK AT AN ARTY UTILITY

Producer: Print 'n' Plotter
Memory Required: 48K
Retail Price: £9.95
Language: Machine code
Author: Joe Gillespie

If you've ever tried to draw a high resolution picture with the bare and BASIC facilities of the Spectrum, you will probably want to investigate the appropriate tools and utilities which exist for this purpose. You have the choice of a hardware-based system using a light pen or a digital tracer with the required software routine/utility, or you can go for a less expensive software solution such as a graphics handling utility program.

Paintbox fits into the second category and covers all aspects of the Spectrum graphics. You may select between the cursor keys, cursor-controlled joystick of the Kempston joystick to use as a 'drawing-pen'. The program is menu driven and splits into two major functions - the UDG creation and handling, and the high resolution screen plotter.

UDG EDITOR

The UDG Editor is excellent; it allows you to create four times as many UDG's as there are in the normal Spectrum BASIC by storing in four banks of 21 UDG sets into memory, which can then be called selectively into the normal UDG area of the Spectrum.

The Editor allows you to view the UDG banks and to recall any of the four banks for editing. Selecting DRAWING BOARD will display the UDG bank, the UDG in magnified form, normally and inverted, and in actual size, and the decimal values for each line. You may call up a normal Spectrum character, an existing UDG character or a blank for editing purposes. Using the cursor keys/joystick and fire button, you can edit or completely redraw the UDG, and when finished, allocate it inside the UDG bank. In doing this, the inverse and rotate (4 x 90°) and mirror image facilities are very helpful.

Having created all the necessary UDG's you can save them on tape together with a machine code routine for manipulating them from BASIC, ready to be recalled in your own programs.

PRECISION PLOTTER

The Precision Plotter is the drawing tool for your high resolution pictures, and provides drawing facilities using the cursor keys/joystick with a constant display of the position co-ordinates. Two moving speeds may be selected by use of the SHIFT key. All the drawing of Spectrum BASIC may be used including: Plot, Draw, Circle, Ink, Over, Copy, Save & Load. Selection of Paper Colour has been omitted from within the screen plotter quite deliberately to avoid the confusions which can arise from the low resolution colour map of the Spectrum (i.e. use of only 2 colours - ink & paper within the 8 x 8 character grid).

This user-protection may be overcome by breaking to the main menu and recalling the screen plotter, whereupon the new paper colour may be selected and the permanent memory screen recalled.

Additionally, there are the following useful facilities; Fill enclosed areas, Erase last operation, Radial Mode - retains starting point of the drawing line in the original plot position, Arc, Cursor Choice - crosswire or dot, Permanent Memory - retains the current screen in memory, Graphics - recalls screen, Break - stores screen in memory and returns to main menu.

IN USE

The UDG Editor and Screen Plotter may be combined by selecting Screen Planner from the Main Menu: all 84 UDG's may be drawn on screen with the high resolution screen as background. The low resolution print coordinates are displayed in this mode, and Ink & Paper colour may be changed. By constantly switching between Screen Planner and Precision Plotter you can build up a picture within the limits of your own imagination and the Spectrum's limited screen display.

The current UDG's may be expanded by loading previously stored UDG banks, thus increasing the amount of UDG's on screen. Throughout Precision Plotter and Screen Planner you may select to save your efforts to tape with a SCREEN$ display file save or with a normal memory file save, which includes the machine code routine for instant recall from BASIC (using RANDOMIZE USR 59980). The memory file, however, must be protected from the BASIC area by lowering RAMTOP to 53059 (with a CLEAR command). The data to screen dump routine may be amended so that multiple screen files may be stored and recalled.

The program proves to be very foolproof in as much that if the permanent memory does get corrupted, there is still the Erase Memory as a backup facility, so you don't risk losing hours of work. Nevertheless, it would be wise to save intermediate results to tape for protection against brown or blackouts!

A commendable effort by Print 'n' Plotter - now if only the package included a pinch of artistic talent, I might be able to draw...

COMMENTS

Control keys: Menu driven, self explanatory - cursors/joystick for positioning, SHIFT for slow movement. Plot = Q, Draw = W, Fill = F, Erase = E, Circle = H, Rad Mode= R, Line Mode=3, Arc = A, Ink = X, Over = N, Permanent Memory = P, Graphics = 9, Dot Cursor = M, Crosswire Cursor = K, Break = CAPSHIFTISPACE, Copy = COPY, Save = S, Load = J.
Sound: none
Features: 24 page booklet and excellent Demo Program

Paintbox is a graphics utility which enables the user to create user-defined graphics and SCREEN$, allowing hi-res sketching with your UDGs.

Peter: The presentation of this program is very good, and the demonstration pictures are excellent. It's very quick to respond, and one of the most outstanding programs I've seen this year.

Stewart: A very impressive graphics utility program which enables quite stunning hi-res pictures to be drawn, saved and used within your own programs.

Stephen: The demonstration contains the best graphics I've ever seen on the Spectrum. To be recommended.

LOAD Paintbox and it'll autoRUN to display the main menu. This serves up a choice of three options: UDG Editor, Precision Plotter and Screen Planner.

Opt for UDG Editor and you're given a further menu which allows you to view existing UDGs, create new UDGs (using Paintbox's Drawing Board) or to go to Sketch Pad. Other options allow for LOAD or SAVE of UDGs from/to tape, the final one being to return to the main menu.

Option 1 - View UDG Banks - displays four sets of UDGs already in memory; you can choose one of these for use with further options. The four banks are (a) a submarine, (b) a warship, (c) aircraft and (d) buildings, trees and vehicles. Also displayed are any UDGs you've already created using option 2 - Drawing Board. This gives you an eight by eight box within which to create your own UDG characters; you can call from one of the banks of UDGs, or you can call a keyboard character and alter that. Designs can be drawn using either the cursor keys or a Kempston Joystick. Once you ve opted to call a character to create or alter, there's no return... you must then create something, even if it's only a space; there's no way you can break out of this part of the program.

Having produced your character, you're then given the opportunity of creating an inverse copy, a mirror image - or even of rotating it through 90 degree steps; whatever it is, just file the result in the bank of UDGs you're working with. There are four banks of 21 UDGs, so it's possible to create a total of 84 different graphic designs; the instructions tell you all you need to know about using banks of UDGs within your own Basic programs.

The Sketch Pad option gives you a six by 30 cell (work area) together with a display of existing UDGs. Here you can try various combinations of UDGs (out of any bank of 21) to see what they look like; if you're planning to use several linked together, make sure they're in the same bank!

The next selection from main menu is the Precision Plotter. You're given the choice of keyboard cursor keys or, again, the Kempston Joystick, and from there you can either start from a blank screen or LOAD a previous file from tape. First choose INK and PAPER colours - then the decision is yours whether to create a new picture, or return to one held in memory. The cursor keys give movement in four directions. Key 'Q' PLOTs a single pixel point and 'W' DRAWs a line from the end of a previous line or pixel point plotted; key 'E' will Erase the last command and 'F' will Fill with the current INK colour. Fill often misses out portions of the screen so you may have to recall it to fill in the 'holes'. Paintbox also supports Circle ('H') and Arc ('A'). INK colour can be changed at any time but PAPER has to be chosen at the time you first enter Precision Plotter. Over ('N') can be useful for correcting minor mistakes and there's a choice of cursor size - cross hairs for general use and a much smaller, single pixel, for precision work. Shift plus cursor keys moves the cursor at a much slower rate - again for fine, careful positioning.

As on Melbourne Draw, the bottom two lines are used as an information window, showing the mode and x/y co-ordinates of the cursor. Here, however, the bottom two lines are not accessible. Should you return to the main menu and then back again to Precision Plotter, key '9' restores the current graphics screen to the display. This is stored in permanent memory, while the program is held in RAM, A COPY of the screen can be printed out on a ZX Printer and the display SAVEd to tape for LOADing later.

Final option served up by the main menu is Screen Planner. This gives you the screen display created with Precision Plotter, together with the ability to call from any of the banks of UDGs. These are displayed on the screen with x and y co-ordinates (now for row and column) and INK and PAPER are available at any time; you can experiment with different attributes, although there doesn't appear to be any option to alter BRIGHT and FLASH at this point. Return to Precision Plotter (via the main menu) and you've now got your composite display to work on.

The instruction booklet gives details of how to call on these SAVEd screens from various memory locations within your own programs. Remember, though, that each screen SAVEd under these conditions uses 6912 bytes. Print 'n' Plotter has a program - Screen Machine - that can save bytes on graphics screens; we'll be looking at that in a future issue.

REMBRANDT & CO

Can't stand the penetrating smell of oil paints and terpentine? Are you drowning in diluted, diffused water colours? Forget about paint brushes, mixing pots and smeary dirty hands. The canvasses of the future are VDU or television screens and the crayons give way to flexible utility programs. Today the applications are limited by the lack of affordable colour screen printouts, but this is bound to change in the near future.

Every artist will confirm that the selection of the right drawing utentils is of prime importance, and we therefore examine four drawing utilities now available to the budding Spectrum artist.

C.A.D. from Dream Software
Dynamic Graphics from Procom
Melbourne Draw from Melbourne House
Paintbox from Print'n'Plotter

Graphical work on the screen may be subdivided into three main activities:

Background and title screen creation
Creation of user definable graphics (UDG)
Handling of moving graphics (Sprites)

The selection of the right utility depends entirely on the specific application. Not all utilities provide facilities for all three disciplines: each one excels in one of the tasks.

SCREEN CREATION

Screen creating can be a very time consuming job. The basics are simple: set or reset the 49'152 pixels which make up the screen and give the 768 attribute positions the required value. If you provide for every pixel a minimum of 10 seconds for setting or resetting, you will have to work non-stop for five days, 16 hours and 32 minutes.

The colouring works out a fraction faster at two hours eight minutes.

Obviously there are alleviating factors which reduce the required time enormously. Not all the screen has to be dealt with on a pixel resolution. Text and fill areas can be handled in character resolution. Nonetheless it is of prime importance that the utility provides an expedient and proficient way of performing screen functions without having to go through any lengthy function select procedures for a simple screen manipulation. Added facilities such as diagonal cursor controls, screen magnification, window creation, scrolling, etc, give the user extra flexibility and can prove a very useful bonus.

Melbourne Draw scores the highest marks in user friendliness. This program provides the clearest logical procedure: screen and attribute handling are completely separated. The screen may at first be edited by positioning the cursor with the eight direction controls and then putting pen to paper for the actual drawing movement. The picture, including the usual edit area, can be created in 'black and white.' When satisfied the attribute edit mode is selected and the identical procedure can take place for the attribute character setting.

Melbourne Draw is the only program which allows the attribute cursor to be moved in a non-destructive (pen up) mode. The colour may be selected by simply pressing the correct colour key (ink and cap shift paper).

Melbourne Draw also provides a screen magnification facility, which can display a portion of the screen four or 16 times enlarged. This proves to be so useful that all the drawing is accomplished on the enlarged scale. The cursor position automatically dictates the screen area displayed and as a further bonus the entire screen may be pixel scrolled to centre the work area. There are no special draw functions such as circle, rectangle, etc, except fill.

The text mode includes the useful option of writing text in any of four orientations (l/r, r/l, u/d, d/u).

The program is aimed at providing a professional drawing board and proves to be a fast and efficient working tool for the serious user.

Dynamic Graphics allows the creation of a window of any size, which may be positioned, edited and copied anywhere on the screen, thus providing for multiple screens or pattern generation within the screen. Further to this there is a rescale option, which will copy any rectangular area of the screen to any other part with different x and y scale. This can prove to be a very potent feature. Special draw commands such as line, circle and edit are also catered for.

Although Dynamic Graphics is first and foremost a moving graphics utility. Its inbuilt screen creator proves to be an exceptionally versatile drawing instrument.

Paintbox offers a Kempston cursor control option with its Precision Plotter screen editor. The inclusion of special draw functions such as fill, erase (last command), circle, radial mode and arc together with the option of including any of the 84 UDGs designed with the UDG editor provide for a useful screen tool. The omission of a paper colour control within the screen editor forces the user to go through the lengthy procedure of returning to the main menu for the sake of changing paper colour.

The list of options in the C.A.D. program suggest a very powerful drawing tool. However the basic command procedure of C.A.D, proves to be a stumbling block. Every function is called by pressing the appropriate command key, upon which the selected command is displayed in the information window. The user must then press enter for execution. This is even required for positioning the cursor. This all makes for a lengthy procedure, which ultimately takes the fun out of drawing. Apart from the usual cursor control there is the option of using memorised headings, but in practice it is very difficult to make good use of it. The shape creation function, which allows the user to stoe and recall a sequence of drawing commands, proves to be very useful for pattern generation or similar applications. C.A.D. has a complete set of special draw commands, which include among other things triangle, 3D cube and 3D rectangle generation.

UDG CREATION

Paintbox offers a complete service for UDG addicts. The program caters for four banks of 21 UDGs which can be called into the UDG area for access. The edit facility is complete and practical to use including inverse, rotating and mirror functions. The UDGs are stored together with a M/C routine for calling the individual banks from Basic into the UDG area. A sketchpad is provided for experimenting with related UDGs (multi-character sprites).

C.A.D. offers a less elaborate UDG facility. Up to 26 UDGs may be edited and stored.

Melbourne Draw has no special editing facility for UDGs but editing is accomplished anywhere on screen using the x16 magnification mode. Any of the 760 character positions on the screen may be assigned as any one of the 22 UDGs. Pixel scrolling may position the required shape within the character grid.

MOVING GRAPHICS

Dynamic Graphics is the only program to actually handle sprites and sprite movement from within a user's Basic program. C.A.D. caters for the creation of up to 40 24x24 pixel sprites (3x3 character), but leaves it to the user to inject any life into the screen. It does not provide any M/C routine for fast pixel to pixel movement.

Dynamic Graphics provides the user with a complete sprite animation facility and must be invaluable for the programmer who doesn't want to delve into the machine code labyrinth but requires smooth animation.

Six sprites of up to 4x4 characters may be generated and edited with the excellent sprite creator. The six graphic characters are treated as individual frames of an animated film and the user may test the resulting motion by selecting the animated display, which sequences the frames on display to create a living object. The character set may then be saved to tape to be called up for later use.

To integrate the moving sprites without any knowledge of M/C, a sprite user subroutine compiler is provided, which creates a sprite positioning subroutine anywhere in normal user memory. This subroutine can be accessed via Randomize User commands from within Basic. Up to 10 different frames may be positioned consecutively on the screen and the result (if handled correctly) is a very smoothly moving object.

CONCLUSION

The four programs under scrutiny all have their individual merits.

Melbourne Draw stands out clearly as a professional tool for title and background screen creations.

Paint box provides the most flexible UDG creator combined with a useful screen editor.

Dynamic Graphics is a must for anybody wishing to create moving graphics within their own programs without bothering about M/C handling.

C.A.D. provides a multitude of different facilities for screen, UDG and sprite editing.

THE PROS AND CONS

C.A.D.
Plus:

- Multitude of special draw functions: Line, rectangle, square, triangle, circle, parallelogram, 3D cube, 3D rectangular box, fill, erase (last command).

- Grid display on edge of screen.

- Assignment of (A-Z) letter labels to 26 points anywhere on screen for 'Draw by letters' facility.

- Shape creation: 26 preprogrammable user commands will perform a series of draw commands (= draw routines).

- Sprite generation: up to 40 3x3 character sprites.

- Sprite generation of up to 40 3x3 character sprites

Minus:
- Complicated and slow drawing procedure (select command and press enter).

- Confusing and unpractical heading facility (cursor or preset heading).

DYNAMIC GRAPHICS
Plus:

- Two cursor speeds.

- Special draw functions: Line, circle, arc, fill.

- Window creation with full edit and positioning facilities.

- Rescale of rectangular area anywhere on screen.

- Excellent sprite creation 4x4 character sprite edit facility including animation experimenting.

- Sprite user subroutine compiler: Creates relocatable M/C routine for handling up to 10 frame 4x4 moving characters from within Basic.

Minus:

- No grid overlay for screen creation.

- Complicated cursor direction controls.

MELBOURNE DRAW
Plus:

- Separate screen and attribute editing.

- Attribute skip (pen up) mode.

- Diagonal cursor movement.

- Magnification x4 and x16 of screen sections.

- Fast screen handling.

- Grid overlay using Bright facility.

- Pixel scrolling of entire screen with wrap around.

- Text can be written in four orientations.

- Reducing and enlarging of entire screen.

- Simple UDG creation of any character on screen.

- Full screen available for drawing (information window relocatable).

Minus:

- Complicated fast cursor movement.

- No special draw commands except fill.

PAINTBOX
Plus:

- Two cursor speeds.

- Kempston cursor control option.

- Special draw facilities: Fill, erase, circle, radial mode arc.

- Excellent UDO creation: four banks of 21 UDGs full UDG edit and handling facility from within Basic.

- Combined screen and UDG facility (Screen Planner).

- Sketchpad for related UDG display during UDG edit.

Minus:

- Long-winded paper colour select.

PACKAGES TO HELP YOU HELP YOURSELF

John Gilbert reviews the programming aids now available for the Spectrum

Most people buy computers with some purpose in mind. A few of them may want to learn about computing and to write programs. It is when that happens that utility routines may be needed to make the task easier.

There is a great variety of utilities available for the Spectrum which compensate for some of the inadequacies. One of the most common types of utility is the toolkit or language extension.

The Spectrum Super Toolkit, from Nectarine, provides all the necessary function a Basic programmer would need. It is also very user-friendly and should help anyone who has the slightest interest in developing programs, no matter whether they be beginner or an expert.

The toolkit will run on the 16K and 48K machine and occupies approximately 2.5K. That means at least 6K on the 16K Spectrum will be available for user programs. That is an achievement for the author, who has included 12 routines in the package.

The exceptional characteristic of the Super Toolkit is the one-key entry system which invokes each of the 12 commands. All you have to do to use a command is hold down the ENTER key and press the command key, such as 'L' for list all variables.

The package is one of the most comprehensive on the market. As well as generating a full re-number of Basic programs, deleting blocks of lines, listing variables and showing the memory used by a program, it will also produce a map of the memory in the computer, including Microdrive and channel information, and read the tape header of any piece of code.

There are no complicated POKEs involved in making any of the utilities work. All you need is a RAND USR instruction to enable and to disable it. You will also have to use the keywords PRINT or REM to re-enable its facilities after running one of your programs.

You should have no difficulty using any of the routines, as the toolkit will produce prompts on the screen for information it needs to perform its work. For instance, when you ask for line renumbering the screen will clear and the computer will ask at which number you want your program lines to start. It will then ask for the step size between each line number. The automatic default, if you press ENTER for each of those prompts, is a line-numbering system starting at 10 and rising in stages.

The manual with the package is just as good as Super Toolkit. It explains each utility command in turn and on the back page provides an uncluttered index of how to access them. It also shows how to turn off the toolkit when you want to use interrupt-driven machine code routines in your programs.

Super Toolkit cannot be recommended strongly enough. It costs £9.95 and fills a big gap in the market.

Spectrum Extended Basic, from CP Software, uses a one-keyword entry system similar to that of the Nectarine toolkit. Once invoked, all the user has to do as type an asterisk and then press the key to activate a desired command. For instance, the 'A' would be pressed if the user wanted to use AUTO line numbering.

The Basic uses approximately 5K of memory in which to operate. Although that is not bad for a package which allows the use of 10 new commands, when compared to the Nectarine product it takes much more memory.

The use of memory by a utility is all-important. A good utility will reside in memory almost invisible to the programmer, who should be able to do anything with the machine except initialise it, and it should utilise as little memory as possible, so that users can write long programs. A utility which uses a great deal of memory defeats its own purpose.

The Extended Basic could be described more accurately as another toolkit and not a set of machine code patch routines on the existing Sinclair Basic. It will operate with the Sinclair language but the routines included in the package are more in line with a toolkit than an extension of a high-level language.

It includes an auto-line number routine, a real-time clock, continuous scroll function, block code delete and an indication of the current state of the computer memory. It is almost as easy to use and as helpful as the Nectarine toolkit and many of its commands can be incorporated into user programs. Extended Basic is not a competitor to the toolkit but it is, however, a useful companion package. Spectrum Extended Basic costs £9.95 and is expensive for what it offers.

The other type of utility which is helpful on the Spectrum is the graphics package Although Sinclair Research included exciting graphics capabilities with the Spectrum, it is often difficult for the programmer working in Basic or the amateur programmer to get the most from the graphics potential.

One of the best ways to highlight a program or give it a title is to increase the size of the lettering and characters on the screen. It could be done with a number of PRINT statements but it is possible, using machine code or POKE routines, to magnify the original character set from the ROM.

A new utility package, Print Utilities, from Sinclair Research will allow you to magnify the character set and also to increase or decrease the width of lettering on the screen or on a printer. The software will allow you to use four widths and two heights.

There are two versions of the package, one for the 48K and one for the 16K, although each performs identical tasks. Once it has been initialised you can set up the character height and width using a print command which employs a hash. After that you must put a CHR$ command and a number. For instance:

PRINT 15; CHR$ 28

would select a double-height character set. Other CHR$ settings would give 32, 42, 16, and 21 characters a line and will also move the cursor left and right and clear the screen.

The different-sized character sets can be used in programs but they can also be used to reproduce listings to make them easier to read. Unfortunately the manual infers that the package is set up for the ZX printer, although with Interface One, which is catered for, output to a dot matrix printer or daisywheel would be possible, using the correct software.

Output to a printer is more difficult than to a screen, as the double-height mode is cancelled after one line is printed and it is not possible to mix different heights in one line of text.

Print Utilities can be obtained for the 48K Spectrum and costs £9.95. For the usefulness of the product that is expensive.

Paintbox is a more powerful graphics utility for the 48K Spectrum. It includes the capacity to manipulate 84 user-definable graphics which are set up in four switchable memory banks. Any one of the four sets can be switched into the 'present' mode, taking the place of the letters A to U.

It is possible to change any of the example characters set up in the package and to save them on tape if you want to use them in your Basic or machine code programs.

Paintbox contains a special facility which enables the user to put several UDG graphics on the screen together to examine the effect. It is also possible to rotate, inverse, and mirror the graphics with the press of a key.

Another facility is the precision plotter, which will allow you to draw pictures on the screen using lines, circles and arcs. The pictures can be shaded with a selected colour and the colour for INK and PAPER can be changed. The utility looks like the one on the Sinclair Horizons tape, although it is set out slightly better and is more usable so far as Basic programming is concerned.

The screen planner uses a combination of UDG graphics which can be created using the UDG banks and the Precision Plotter.

It allows you to see the finished result of all your work. The package is a powerful graphics aid and, if the demonstrations are any criterion both in the manual and on the tape you could produce some professional screen displays. It is possible for even a beginner to draw reasonable pictures using the package. Paintbox can be obtained from Print and Plotter and costs £7.50.

There are still few utility packages available for the Spectrum and the computer has been on the market for nearly one-and-a-half-years. It seems that most software companies are concentrating on producing arcade games of one kind or another. That is unfortunate, as many Spectrum owners could produce original and interesting programs if they had access to more utilities. It might also encourage more people to start programming if the see what can be done with the utilities available,

Some people may say that it is a little late to start thinking of producing more utilities for Spectrum owners but there are still many users trying to find interesting things to do with a computer. It would certainly be helpful if the few utilities on the market at present became many in the near future.

Nectarine, 837 Yeovil Road, Slough, Berkshire.

CP Software, 17 Orchard Lane, Prestwood, Bucks HP16 0NN.

Sinclair Research, Stanhope Road, Camberley, Surrey GU15 3PS,

Print and Plotter, 19 Borough High Street, London SE1 9SE.

QUICKSOFT

Clive Smith reviews some of the more unusual programs on the market.

I must admit I've never had so much fun with a utility program as with this one. Paintbox enables you to make up your own UDGs with ease, plot and draw by simple cursor movements, fill in your drawings and save screens for use in your programs. It is written by Joe Gillespie for the 48K Spectrum and is supplied with an easy to follow instruction booklet.

It won't make you an artist overnight but after a couple of hours of loading the tape and reading the instructions I managed to draw this picture...

As you can see I'm no Picasso! Paintbox does, however, have more serious applications than drawing funny pictures; as an aid in drawing graphs or in technical drawings and so on.

Once you have loaded the tape, you are presented with a menu. From there you can view the available UDG bank; there are up to 84 user-defined characters in store.

If you don't like the available choice, you can invent your own by calling up the drawing board. This enables you to plot your shape on a 8x8 grid by using a cursor. Once made, you then store it in one of the four banks.

Another facility on the menu is "Sketch pad". Here you can practice building up a picture using UDGs before entering them onto your main picture. To build up your picture you first hit the 'Precision Plotter' key. Now the fun bit starts.

You are presented with a blank screen apart from a cursor which can either be moved via the keyboard or a joystick. In the bottom right hand of the screen you are given an X and Y coordinate of the cursor. To draw a line you move the cursor to where you want the line to start and press the PLOT key. Moving the cursor to the place where you want the line to end and pressing the DRAW key will instantly produce your line.

Paintbox has facilities to draw circles and arcs and in radial mode, will return the cursor to the start of your line; ideal if you are drawing a spoked wheel. Once you have outlined your picture, you can shade in any of the parts with different ink colours. Finally, you can put on your UDGs to complete the picture.

If you make a mistake you can edit your last command. As you build up your picture it can be stored in memory and recalled at any time. Your picture can then be stored on tape and reproduced either as a screen$ or as memory bytes. It's possible to store up to five screens and this will leave you with about 6K of memory.

To give you some idea what is possible with this program, have a look at one of the colour adverts in your magazine and take a close look at some of the drawings. With a little practice you will find that it's quite possible to draw pictures of that standard.

The tape costs £7.50 and I think you'll find it's the best £7.50's worth you have ever spent. Print n Plotter products also sell some support hardware to go with it such as key overlays and a jotter pad.

Print n Plotter Products are at Dept ZX, 19 Borough High Street, London SE1 9SE.

DESIGNS FOR LIVING

Colin Christmas tkaes a further look at computer art.

Still hooked on Graphics? Well don't be afraid to admit it, some of us addicts are often mistaken for respectable members of society, and some of us are regular readers of ZX Computing. And while we're on the subject, it's worth a reminder to check back over the past three or four issues of the magazine to see just how much there is to be getting on with for the more enthusiastic programmer who really wants to come to grips with the theoretical and technical aspects of using the graphics and design potential of the micro.

I have great respect and admiration for such enthusiasts, If I wore one, I'd raise my hat to them. I don't, so this vote of thanks will have to do. Other enthusiasts such as myself tend to start about half way through the process. In other words, when most of the hard work has been done and the programs and the hardware have been produced. Lazy? Incompetent? Possibly, but it takes all sorts.

In the last issue I looked at the growing potential of graphics pads generally and of the RD Digital Tracer and Dream Software's CAD package specifically with reference to graphics and design work. However two other, more established "tools" for the graphics design specialist also merit serious consideration.

LA PLUME DE MA MICRO

Light pens for use by Micro users have been around for a long time now. Opinions as to their usefulness and value for money vary of course. Recently I've been using the LIGHT PEN produced by DK'TRONICS for the 16 and 48K Spectrum.

The package consists of a program on cassette, an instruction booklet, the pen itself and a control interface which is plugged into the back of the computer.

The interface is compact and well designed and fits neatly and reassuringly into the port. The metre long lead from the pen is fitted with a jackplug which plugs firmly into a socket located on the top of the interface housing. The booklet in fact is one of the best I've seen. It is informative, brief, easy to follow and includes a section at the end on "error conditions" which might be encountered.

The program contains several routines which enable the user to select from sixteen functions. These are displayed as a menu on the bottom two lines of the screen. This means the drawing area is always clear. In order to select a function once the program has been loaded you simply point the pen at the letter or box displayed on the menu and press any key. This is made possible by a machine code routine, one of the several provided.

The program uses two variables called "origin" and "target" which need to be positioned on the screen in order to determine the co-ordinates required for drawing lines, corners of boxes, centres and circumferences of circles, define arcs and so on. The full menu also enables the user to erase the line, circle, box or whatever has just been drawn, to ink in shapes, to set border, ink and paper colour, to draw freehand and to clear the screen. Screens can be SAVED or LOADed from tape or can be kept in memory for later recall.

Text can also be inserted into the display. Several of the functions require definite steps which must be followed before the command can be carried out. These are well laid out in the instruction manual. At first it seems as if these separate steps are going to prove tedious and cumbersome but it is surprising how quickly one becomes familiar with them.

SET UP

Some people will also find the calibration routine at the beginning of the program annoying. The brightness, contrast and colour controls of the T.V. set they are using may have to be adjusted before the pen can be positioned accurately. I've tried the pen with a Black and White set and this only seems to treble the problems of calibration. I have to confess that I pronounced it's use with Black and White set more nuisance than it was worth.

One last piece of advice, when using a lightpen give some thought to where you position your micro in relation to your screen. Ideally it should go underneath the screen or beside it, for most of us on the left. Remember that your main working area is the screen itself and you need to be able to work there freely and without developing arm strain.

High marks then for one of the most recent lightpens to come onto the market. Something I neglected to say is that it has so far proved to be very reliable. Not so I'm afraid with another lightpen I've been trying to use, the TROJAN.

I've read elsewhere that there were probelms of compatibility with the early TROJAN Lightpens and the newer Spectrums. I'm assured that I've got one of the new lightpens. Sorry, Trojan Products, but mine has been giving me grey hairs just where they are not welcome - in amongst the few I've already got. The most common problem being that the program seems to jump between commands or to stick in commands. At best erratic and unreliable, at worst, it seems to crash.

THE SOFTWARE SOLUTION

A Utility which has also been with us for a while now but which is still capable of straining the imagination is PAINTBOX from PRINT 'N' PLOTTER PRODUCTS. Again, it's now only one of the many Graphics packages available from the Spectrum but it's certainly worth serious consideration nevertheless.

It claims to be "ingenious", "unique", "the most imaginative." in the cold light of the monitor screen may I offer Impressive and Comprehensive as more critical alternatives?

This graphics programming tool-kit for the 48K Spectrum consists of a cassette containing two programs, one on each side. One to demonstrate some of the results which can be achieved. The other with the machine code program which enables you to do all the work. There is also a twenty eight page book to take you through this supermarket of graphics 'deals', it contains a lot of detail and the print is small.

Working through it is not easy but it is written well and conveys real excitement and enthusiasm for the tasks involved. In the end it's a smooth ride and it gets easier to use.

The main menu, as you would expect, is displayed once the program is loaded. Before you move on you have a choice of cursor control, keyboard or Kempston Joystick, although other joysticks may be used. If you then choose Menu 1 - most Games enthusiasts do, you can explore the UDG Editor.

Without affecting the normal character set you can program up to 84 user definable characters and locate this set into your own written programs. This is made possible by storing 4 Banks of characters in memory and recalling them at any time into the usual UDG area by a built in short machine code routine. There is of course a facility of both saving all four banks to tape and loading pre-recorded banks.

Sketch Pad, next off the main menu, puts on the screen a small 'try out' area for related characters before they are used in screen graphics or programs. The current UDG file appears at the top of the screen.

FOOD FOR THOUGHT

As you continue to work through the Menu like some gourmet in a great restaurant, you discover how to define any or all of the 84 characters available and put them in position, then put them into your own programs.

High resolution screen graphic work can be attempted using the Precision Plotter section of the program. The format will be familiar. Plot, draw, fill. erase, circle, radials and arc, together with choice of ink, cursor and with some difficulty paper colour. The cursor moves smoothly and quite quickly as you work. However, sometimes it is useful to be able to move the cursor with great precision and accuracy. This also is possible by keeping the SHIFT key pressed during movement. I was very impressed with the action and ease with which one could wrk with this section.

Moving on quickly, the rest of the program offers a Screen Planner where your graphics produced using Precision Plotter can be combined with the UDG's you defined and stored in any or all of the four UDG Banks. Procedures are given for achieving Multiple Screen Files. A short machine code routine, used as a memory file, when called transfers data to the screen as a picture. This data call can be held permanently above RAMTOP and called at any time.

Impressive and comprehensive, it is a fairly powerful Graphics aid, above all, it is fun to use and experiment with. The more you use it, the bolder and more adventurous you become.

STATE OF THE ART

It is usual to talk of exploring the potential of our micros when discussing the hardware and software available for say Graphics and Design. It seems to me that together they offer a challenge to us, the users, to explore our own potential to make, create and design.

A challenge not our powers of logical thinking or convergence thinking, but to our powers of divergent thinking. As users it's up to us to take up the challenge. What can we achieve, making use of lightpens, tracers graphics tool-kits and so on?

It's difficult trying to imagine a young Leonardo da Vinci sitting down with paper, canvas, pens, inks, brushes and paints sucking his thumb and wondering, "Well what do they expect me to do with this lot? " There may not be many Leonardos amongst us, but the challenge remains. What CAN we do with this lot?

And I don't just mean Games.........